diff --git a/rskj-core/src/main/java/co/rsk/peg/bitcoin/BitcoinUtils.java b/rskj-core/src/main/java/co/rsk/peg/bitcoin/BitcoinUtils.java
index f23537a9e05..1bf670b7af3 100644
--- a/rskj-core/src/main/java/co/rsk/peg/bitcoin/BitcoinUtils.java
+++ b/rskj-core/src/main/java/co/rsk/peg/bitcoin/BitcoinUtils.java
@@ -25,13 +25,10 @@ public static Optional<Sha256Hash> getFirstInputSigHash(BtcTransaction btcTx){
         }
         TransactionInput txInput = btcTx.getInput(FIRST_INPUT_INDEX);
         Optional<Script> redeemScript = extractRedeemScriptFromInput(txInput);
-        if (!redeemScript.isPresent()) {
-            return Optional.empty();
-        }
 
-        return Optional.of(btcTx.hashForSignature(
+        return redeemScript.map(script -> btcTx.hashForSignature(
             FIRST_INPUT_INDEX,
-            redeemScript.get(),
+            script,
             BtcTransaction.SigHash.ALL,
             false
         ));
diff --git a/rskj-core/src/main/java/co/rsk/peg/bitcoin/ErpRedeemScriptBuilder.java b/rskj-core/src/main/java/co/rsk/peg/bitcoin/ErpRedeemScriptBuilder.java
index cc15f0bd9a9..f7575f73918 100644
--- a/rskj-core/src/main/java/co/rsk/peg/bitcoin/ErpRedeemScriptBuilder.java
+++ b/rskj-core/src/main/java/co/rsk/peg/bitcoin/ErpRedeemScriptBuilder.java
@@ -2,14 +2,14 @@
 
 import co.rsk.bitcoinj.core.BtcECKey;
 import co.rsk.bitcoinj.script.Script;
-
 import java.util.List;
 
 public interface ErpRedeemScriptBuilder {
-
-    Script createRedeemScriptFromKeys(List<BtcECKey> defaultPublicKeys,
-                              int defaultThreshold,
-                              List<BtcECKey> emergencyPublicKeys,
-                              int emergencyThreshold,
-                              long csvValue);
+    Script of(
+        List<BtcECKey> defaultPublicKeys,
+        int defaultThreshold,
+        List<BtcECKey> emergencyPublicKeys,
+        int emergencyThreshold,
+        long csvValue
+    );
 }
diff --git a/rskj-core/src/main/java/co/rsk/peg/bitcoin/ErpRedeemScriptBuilderUtils.java b/rskj-core/src/main/java/co/rsk/peg/bitcoin/ErpRedeemScriptBuilderUtils.java
index 0264868a975..6dde98b3030 100644
--- a/rskj-core/src/main/java/co/rsk/peg/bitcoin/ErpRedeemScriptBuilderUtils.java
+++ b/rskj-core/src/main/java/co/rsk/peg/bitcoin/ErpRedeemScriptBuilderUtils.java
@@ -1,21 +1,19 @@
 package co.rsk.peg.bitcoin;
 
+import static co.rsk.peg.bitcoin.RedeemScriptCreationException.Reason.INVALID_CSV_VALUE;
+import static co.rsk.peg.bitcoin.RedeemScriptCreationException.Reason.INVALID_INTERNAL_REDEEM_SCRIPTS;
+
 import co.rsk.bitcoinj.script.Script;
 import co.rsk.bitcoinj.script.ScriptChunk;
+import java.util.List;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.util.List;
-
-import static co.rsk.peg.bitcoin.RedeemScriptCreationException.Reason.INVALID_CSV_VALUE;
-import static co.rsk.peg.bitcoin.RedeemScriptCreationException.Reason.INVALID_INTERNAL_REDEEM_SCRIPTS;
-
 public class ErpRedeemScriptBuilderUtils {
     private static final Logger logger = LoggerFactory.getLogger(ErpRedeemScriptBuilderUtils.class);
-    public static final long MAX_CSV_VALUE = 65535L; // 2^16 - 1, since bitcoin will interpret up to 16 bits as the CSV value
+    public static final long MAX_CSV_VALUE = 65_535L; // 2^16 - 1, since bitcoin will interpret up to 16 bits as the CSV value
 
-    private ErpRedeemScriptBuilderUtils() {
-    }
+    private ErpRedeemScriptBuilderUtils() {}
 
     public static List<ScriptChunk> removeOpCheckMultisig(Script redeemScript) {
         return redeemScript.getChunks().subList(0, redeemScript.getChunks().size() - 1);
@@ -27,7 +25,6 @@ public static void validateRedeemScriptValues(
         Long csvValue
     ) {
         if (!defaultFederationRedeemScript.isSentToMultiSig() || !erpFederationRedeemScript.isSentToMultiSig()) {
-
             String message = "Provided redeem scripts have an invalid structure, not standard";
             logger.debug(
                 "[validateRedeemScriptValues] {}. Default script {}. Emergency script {}",
diff --git a/rskj-core/src/main/java/co/rsk/peg/bitcoin/FlyoverRedeemScriptBuilder.java b/rskj-core/src/main/java/co/rsk/peg/bitcoin/FlyoverRedeemScriptBuilder.java
new file mode 100644
index 00000000000..f7766c54fde
--- /dev/null
+++ b/rskj-core/src/main/java/co/rsk/peg/bitcoin/FlyoverRedeemScriptBuilder.java
@@ -0,0 +1,8 @@
+package co.rsk.peg.bitcoin;
+
+import co.rsk.bitcoinj.script.Script;
+import co.rsk.crypto.Keccak256;
+
+public interface FlyoverRedeemScriptBuilder {
+    Script of(Keccak256 flyoverDerivationHash, Script redeemScript);
+}
diff --git a/rskj-core/src/main/java/co/rsk/peg/bitcoin/FlyoverRedeemScriptBuilderImpl.java b/rskj-core/src/main/java/co/rsk/peg/bitcoin/FlyoverRedeemScriptBuilderImpl.java
new file mode 100644
index 00000000000..a11199bf9a4
--- /dev/null
+++ b/rskj-core/src/main/java/co/rsk/peg/bitcoin/FlyoverRedeemScriptBuilderImpl.java
@@ -0,0 +1,43 @@
+package co.rsk.peg.bitcoin;
+
+import static co.rsk.peg.bitcoin.RedeemScriptCreationException.Reason.INVALID_FLYOVER_DERIVATION_HASH;
+import static java.util.Objects.isNull;
+
+import co.rsk.bitcoinj.script.Script;
+import co.rsk.bitcoinj.script.ScriptBuilder;
+import co.rsk.bitcoinj.script.ScriptOpCodes;
+import co.rsk.crypto.Keccak256;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class FlyoverRedeemScriptBuilderImpl implements FlyoverRedeemScriptBuilder {
+    private static final Logger logger = LoggerFactory.getLogger(FlyoverRedeemScriptBuilderImpl.class);
+
+    private FlyoverRedeemScriptBuilderImpl() {}
+
+    public static FlyoverRedeemScriptBuilderImpl builder() {
+        return new FlyoverRedeemScriptBuilderImpl();
+    }
+
+    @Override
+    public Script of(Keccak256 flyoverDerivationHash, Script redeemScript) {
+        validateFlyoverDerivationHash(flyoverDerivationHash);
+
+        ScriptBuilder scriptBuilder = new ScriptBuilder();
+        byte[] flyoverDerivationHashSerialized = flyoverDerivationHash.getBytes();
+
+        return scriptBuilder
+            .data(flyoverDerivationHashSerialized)
+            .op(ScriptOpCodes.OP_DROP)
+            .addChunks(redeemScript.getChunks())
+            .build();
+    }
+
+    private void validateFlyoverDerivationHash(Keccak256 flyoverDerivationHash) {
+        if (isNull(flyoverDerivationHash) || flyoverDerivationHash.equals(Keccak256.ZERO_HASH)) {
+            String message = String.format("Provided flyover derivation hash %s is invalid.", flyoverDerivationHash);
+            logger.warn("[validateFlyoverDerivationHash] {}", message);
+            throw new RedeemScriptCreationException(message, INVALID_FLYOVER_DERIVATION_HASH);
+        }
+    }
+}
diff --git a/rskj-core/src/main/java/co/rsk/peg/bitcoin/NonStandardErpRedeemScriptBuilder.java b/rskj-core/src/main/java/co/rsk/peg/bitcoin/NonStandardErpRedeemScriptBuilder.java
index 8079926dfb7..5abbec42e2e 100644
--- a/rskj-core/src/main/java/co/rsk/peg/bitcoin/NonStandardErpRedeemScriptBuilder.java
+++ b/rskj-core/src/main/java/co/rsk/peg/bitcoin/NonStandardErpRedeemScriptBuilder.java
@@ -1,25 +1,33 @@
 package co.rsk.peg.bitcoin;
 
+import static co.rsk.peg.bitcoin.ErpRedeemScriptBuilderUtils.removeOpCheckMultisig;
+
 import co.rsk.bitcoinj.core.BtcECKey;
 import co.rsk.bitcoinj.core.Utils;
-import co.rsk.bitcoinj.script.*;
+import co.rsk.bitcoinj.script.Script;
+import co.rsk.bitcoinj.script.ScriptBuilder;
+import co.rsk.bitcoinj.script.ScriptOpCodes;
+import java.util.List;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.util.List;
-
-import static co.rsk.peg.bitcoin.ErpRedeemScriptBuilderUtils.removeOpCheckMultisig;
-
 public class NonStandardErpRedeemScriptBuilder implements ErpRedeemScriptBuilder {
     private static final Logger logger = LoggerFactory.getLogger(NonStandardErpRedeemScriptBuilder.class);
 
-    @Override
-    public Script createRedeemScriptFromKeys(List<BtcECKey> defaultPublicKeys,
-                                             int defaultThreshold,
-                                             List<BtcECKey> emergencyPublicKeys,
-                                             int emergencyThreshold,
-                                             long csvValue) {
+    private NonStandardErpRedeemScriptBuilder() {}
+
+    public static NonStandardErpRedeemScriptBuilder builder() {
+        return new NonStandardErpRedeemScriptBuilder();
+    }
 
+    @Override
+    public Script of(
+        List<BtcECKey> defaultPublicKeys,
+        int defaultThreshold,
+        List<BtcECKey> emergencyPublicKeys,
+        int emergencyThreshold,
+        long csvValue
+    ) {
         Script defaultRedeemScript = ScriptBuilder.createRedeemScript(defaultThreshold, defaultPublicKeys);
         Script emergencyRedeemScript = ScriptBuilder.createRedeemScript(emergencyThreshold, emergencyPublicKeys);
 
@@ -33,13 +41,13 @@ public Script createRedeemScriptFromKeys(List<BtcECKey> defaultPublicKeys,
         ScriptValidations.validateScriptSize(redeemScript);
 
         return redeemScript;
-
     }
 
-    private Script createRedeemScriptFromScripts(Script defaultRedeemScript,
-                                                        Script emergencyRedeemScript,
-                                                        byte[] serializedCsvValue) {
-
+    private Script createRedeemScriptFromScripts(
+        Script defaultRedeemScript,
+        Script emergencyRedeemScript,
+        byte[] serializedCsvValue
+    ) {
         ScriptBuilder scriptBuilder = new ScriptBuilder();
         return scriptBuilder
             .op(ScriptOpCodes.OP_NOTIF)
diff --git a/rskj-core/src/main/java/co/rsk/peg/bitcoin/NonStandardErpRedeemScriptBuilderFactory.java b/rskj-core/src/main/java/co/rsk/peg/bitcoin/NonStandardErpRedeemScriptBuilderFactory.java
index b946fa8760e..e8f8b376d36 100644
--- a/rskj-core/src/main/java/co/rsk/peg/bitcoin/NonStandardErpRedeemScriptBuilderFactory.java
+++ b/rskj-core/src/main/java/co/rsk/peg/bitcoin/NonStandardErpRedeemScriptBuilderFactory.java
@@ -10,15 +10,16 @@ private NonStandardErpRedeemScriptBuilderFactory() {}
 
     public static ErpRedeemScriptBuilder getNonStandardErpRedeemScriptBuilder(
         ActivationConfig.ForBlock activations,
-        NetworkParameters networkParameters) {
-
+        NetworkParameters networkParameters
+    ) {
         if (networkIsTestnet(networkParameters) && !activations.isActive(ConsensusRule.RSKIP284)) {
-            return new NonStandardErpRedeemScriptBuilderHardcoded();
+            return NonStandardErpRedeemScriptBuilderHardcoded.builder();
         }
         if (!activations.isActive(ConsensusRule.RSKIP293)) {
-            return new NonStandardErpRedeemScriptBuilderWithCsvUnsignedBE();
+            return NonStandardErpRedeemScriptBuilderWithCsvUnsignedBE.builder();
         }
-        return new NonStandardErpRedeemScriptBuilder();
+
+        return NonStandardErpRedeemScriptBuilder.builder();
     }
 
     private static boolean networkIsTestnet(NetworkParameters networkParameters) {
diff --git a/rskj-core/src/main/java/co/rsk/peg/bitcoin/NonStandardErpRedeemScriptBuilderHardcoded.java b/rskj-core/src/main/java/co/rsk/peg/bitcoin/NonStandardErpRedeemScriptBuilderHardcoded.java
index 7e2f517f51b..8e62eda354d 100644
--- a/rskj-core/src/main/java/co/rsk/peg/bitcoin/NonStandardErpRedeemScriptBuilderHardcoded.java
+++ b/rskj-core/src/main/java/co/rsk/peg/bitcoin/NonStandardErpRedeemScriptBuilderHardcoded.java
@@ -2,23 +2,29 @@
 
 import co.rsk.bitcoinj.core.BtcECKey;
 import co.rsk.bitcoinj.script.Script;
+import java.util.List;
 import org.bouncycastle.util.encoders.Hex;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.util.List;
-
 public class NonStandardErpRedeemScriptBuilderHardcoded implements ErpRedeemScriptBuilder {
     private static final Logger logger = LoggerFactory.getLogger(NonStandardErpRedeemScriptBuilderHardcoded.class);
     private static final byte[] LEGACY_ERP_TESTNET_REDEEM_SCRIPT_BYTES = Hex.decode("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");
 
-    @Override
-    public Script createRedeemScriptFromKeys(List<BtcECKey> defaultPublicKeys,
-                                     int defaultThreshold,
-                                     List<BtcECKey> emergencyPublicKeys,
-                                     int emergencyThreshold,
-                                     long csvValue) {
+    private NonStandardErpRedeemScriptBuilderHardcoded() {}
 
+    public static NonStandardErpRedeemScriptBuilderHardcoded builder() {
+        return new NonStandardErpRedeemScriptBuilderHardcoded();
+    }
+
+    @Override
+    public Script of(
+        List<BtcECKey> defaultPublicKeys,
+        int defaultThreshold,
+        List<BtcECKey> emergencyPublicKeys,
+        int emergencyThreshold,
+        long csvValue
+    ) {
         logger.debug("[getRedeemScript] Returning hardcoded redeem script");
         return new Script(LEGACY_ERP_TESTNET_REDEEM_SCRIPT_BYTES);
     }
diff --git a/rskj-core/src/main/java/co/rsk/peg/bitcoin/NonStandardErpRedeemScriptBuilderWithCsvUnsignedBE.java b/rskj-core/src/main/java/co/rsk/peg/bitcoin/NonStandardErpRedeemScriptBuilderWithCsvUnsignedBE.java
index c70d9c25c6a..2f083b27729 100644
--- a/rskj-core/src/main/java/co/rsk/peg/bitcoin/NonStandardErpRedeemScriptBuilderWithCsvUnsignedBE.java
+++ b/rskj-core/src/main/java/co/rsk/peg/bitcoin/NonStandardErpRedeemScriptBuilderWithCsvUnsignedBE.java
@@ -1,28 +1,34 @@
 package co.rsk.peg.bitcoin;
 
+import static co.rsk.peg.bitcoin.ErpRedeemScriptBuilderUtils.removeOpCheckMultisig;
+
 import co.rsk.bitcoinj.core.BtcECKey;
 import co.rsk.bitcoinj.core.Utils;
 import co.rsk.bitcoinj.script.Script;
 import co.rsk.bitcoinj.script.ScriptBuilder;
 import co.rsk.bitcoinj.script.ScriptOpCodes;
+import java.util.List;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.util.List;
-
-import static co.rsk.peg.bitcoin.ErpRedeemScriptBuilderUtils.removeOpCheckMultisig;
-
 public class NonStandardErpRedeemScriptBuilderWithCsvUnsignedBE implements ErpRedeemScriptBuilder {
     private static final Logger logger = LoggerFactory.getLogger(NonStandardErpRedeemScriptBuilderWithCsvUnsignedBE.class);
     private static final int CSV_BYTES_NEEDED_LENGTH = 2;
 
-    @Override
-    public Script createRedeemScriptFromKeys(List<BtcECKey> defaultPublicKeys,
-                                             int defaultThreshold,
-                                             List<BtcECKey> emergencyPublicKeys,
-                                             int emergencyThreshold,
-                                             long csvValue) {
+    private NonStandardErpRedeemScriptBuilderWithCsvUnsignedBE() {}
+
+    public static NonStandardErpRedeemScriptBuilderWithCsvUnsignedBE builder() {
+        return new NonStandardErpRedeemScriptBuilderWithCsvUnsignedBE();
+    }
 
+    @Override
+    public Script of(
+        List<BtcECKey> defaultPublicKeys,
+        int defaultThreshold,
+        List<BtcECKey> emergencyPublicKeys,
+        int emergencyThreshold,
+        long csvValue
+    ) {
         Script defaultRedeemScript = ScriptBuilder.createRedeemScript(defaultThreshold, defaultPublicKeys);
         Script emergencyRedeemScript = ScriptBuilder.createRedeemScript(emergencyThreshold, emergencyPublicKeys);
 
@@ -36,13 +42,13 @@ public Script createRedeemScriptFromKeys(List<BtcECKey> defaultPublicKeys,
         ScriptValidations.validateScriptSize(redeemScript);
         
         return redeemScript;
-
     }
 
-    private Script createRedeemScriptFromScripts(Script defaultRedeemScript,
-                                                        Script emergencyRedeemScript,
-                                                        byte[] serializedCsvValue) {
-
+    private Script createRedeemScriptFromScripts(
+        Script defaultRedeemScript,
+        Script emergencyRedeemScript,
+        byte[] serializedCsvValue
+    ) {
         ScriptBuilder scriptBuilder = new ScriptBuilder();
         return scriptBuilder
             .op(ScriptOpCodes.OP_NOTIF)
diff --git a/rskj-core/src/main/java/co/rsk/peg/bitcoin/P2shErpRedeemScriptBuilder.java b/rskj-core/src/main/java/co/rsk/peg/bitcoin/P2shErpRedeemScriptBuilder.java
index 42c3bf6ad7c..93e381f3891 100644
--- a/rskj-core/src/main/java/co/rsk/peg/bitcoin/P2shErpRedeemScriptBuilder.java
+++ b/rskj-core/src/main/java/co/rsk/peg/bitcoin/P2shErpRedeemScriptBuilder.java
@@ -5,21 +5,27 @@
 import co.rsk.bitcoinj.script.Script;
 import co.rsk.bitcoinj.script.ScriptBuilder;
 import co.rsk.bitcoinj.script.ScriptOpCodes;
+import java.util.List;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.util.List;
-
 public class P2shErpRedeemScriptBuilder implements ErpRedeemScriptBuilder{
     private static final Logger logger = LoggerFactory.getLogger(P2shErpRedeemScriptBuilder.class);
 
-    @Override
-    public Script createRedeemScriptFromKeys(List<BtcECKey> defaultPublicKeys,
-                                             int defaultThreshold,
-                                             List<BtcECKey> emergencyPublicKeys,
-                                             int emergencyThreshold,
-                                             long csvValue) {
+    private P2shErpRedeemScriptBuilder() {}
 
+    public static P2shErpRedeemScriptBuilder builder() {
+        return new P2shErpRedeemScriptBuilder();
+    }
+
+    @Override
+    public Script of(
+        List<BtcECKey> defaultPublicKeys,
+        int defaultThreshold,
+        List<BtcECKey> emergencyPublicKeys,
+        int emergencyThreshold,
+        long csvValue
+    ) {
         Script defaultRedeemScript = ScriptBuilder.createRedeemScript(defaultThreshold, defaultPublicKeys);
         Script emergencyRedeemScript = ScriptBuilder.createRedeemScript(emergencyThreshold, emergencyPublicKeys);
 
@@ -34,10 +40,12 @@ public Script createRedeemScriptFromKeys(List<BtcECKey> defaultPublicKeys,
 
         return redeemScript;
     }
-    private Script createRedeemScriptFromScripts(Script defaultRedeemScript,
-                                     Script emergencyRedeemScript,
-                                     byte[] serializedCsvValue) {
 
+    private Script createRedeemScriptFromScripts(
+        Script defaultRedeemScript,
+        Script emergencyRedeemScript,
+        byte[] serializedCsvValue
+    ) {
         ScriptBuilder scriptBuilder = new ScriptBuilder();
 
         return scriptBuilder
diff --git a/rskj-core/src/main/java/co/rsk/peg/bitcoin/RedeemScriptCreationException.java b/rskj-core/src/main/java/co/rsk/peg/bitcoin/RedeemScriptCreationException.java
index ba90caa3a5e..a35c51a7b56 100644
--- a/rskj-core/src/main/java/co/rsk/peg/bitcoin/RedeemScriptCreationException.java
+++ b/rskj-core/src/main/java/co/rsk/peg/bitcoin/RedeemScriptCreationException.java
@@ -5,7 +5,8 @@ public class RedeemScriptCreationException extends RuntimeException {
 
     public enum Reason {
         INVALID_INTERNAL_REDEEM_SCRIPTS,
-        INVALID_CSV_VALUE
+        INVALID_CSV_VALUE,
+        INVALID_FLYOVER_DERIVATION_HASH
     }
 
     public RedeemScriptCreationException(String s, Reason reason) {
diff --git a/rskj-core/src/main/java/co/rsk/peg/federation/ErpFederation.java b/rskj-core/src/main/java/co/rsk/peg/federation/ErpFederation.java
index 310de38e915..ab119a539a3 100644
--- a/rskj-core/src/main/java/co/rsk/peg/federation/ErpFederation.java
+++ b/rskj-core/src/main/java/co/rsk/peg/federation/ErpFederation.java
@@ -19,9 +19,10 @@
 public class ErpFederation extends Federation {
     private final List<BtcECKey> erpPubKeys;
     private final long activationDelay;
+    private final ErpRedeemScriptBuilder erpRedeemScriptBuilder;
+
     private Script defaultRedeemScript;
     private Script defaultP2SHScript;
-    private final ErpRedeemScriptBuilder erpRedeemScriptBuilder;
 
     protected ErpFederation(
         FederationArgs federationArgs,
@@ -64,7 +65,7 @@ public Script getDefaultRedeemScript() {
     public Script getRedeemScript() {
         if (redeemScript == null) {
             try {
-                redeemScript = erpRedeemScriptBuilder.createRedeemScriptFromKeys(
+                redeemScript = erpRedeemScriptBuilder.of(
                     getBtcPublicKeys(),
                     getNumberOfSignaturesRequired(),
                     erpPubKeys,
@@ -99,5 +100,4 @@ private void validateEmergencyKeys(List<BtcECKey> erpPubKeys) {
             throw new ErpFederationCreationException(message, NULL_OR_EMPTY_EMERGENCY_KEYS);
         }
     }
-
 }
diff --git a/rskj-core/src/main/java/co/rsk/peg/federation/FederationFactory.java b/rskj-core/src/main/java/co/rsk/peg/federation/FederationFactory.java
index 28ff1b9f48f..7a55bf916a1 100644
--- a/rskj-core/src/main/java/co/rsk/peg/federation/FederationFactory.java
+++ b/rskj-core/src/main/java/co/rsk/peg/federation/FederationFactory.java
@@ -1,14 +1,14 @@
 package co.rsk.peg.federation;
 
+import static co.rsk.peg.federation.FederationFormatVersion.*;
+
 import co.rsk.bitcoinj.core.BtcECKey;
 import co.rsk.bitcoinj.core.NetworkParameters;
 import co.rsk.peg.bitcoin.ErpRedeemScriptBuilder;
 import co.rsk.peg.bitcoin.NonStandardErpRedeemScriptBuilderFactory;
 import co.rsk.peg.bitcoin.P2shErpRedeemScriptBuilder;
-import org.ethereum.config.blockchain.upgrades.ActivationConfig;
 import java.util.List;
-
-import static co.rsk.peg.federation.FederationFormatVersion.*;
+import org.ethereum.config.blockchain.upgrades.ActivationConfig;
 
 public class FederationFactory {
 
@@ -22,25 +22,38 @@ public static StandardMultisigFederation buildStandardMultiSigFederation(Federat
         );
     }
 
-    public static ErpFederation buildNonStandardErpFederation(FederationArgs federationArgs,
-                                                              List<BtcECKey> erpPubKeys,
-                                                              long activationDelay,
-                                                              ActivationConfig.ForBlock activations) {
+    public static ErpFederation buildNonStandardErpFederation(
+        FederationArgs federationArgs,
+        List<BtcECKey> erpPubKeys,
+        long activationDelay,
+        ActivationConfig.ForBlock activations
+    ) {
         NetworkParameters btcParams = federationArgs.getBtcParams();
         ErpRedeemScriptBuilder erpRedeemScriptBuilder =
             NonStandardErpRedeemScriptBuilderFactory.getNonStandardErpRedeemScriptBuilder(activations, btcParams);
 
-        return new ErpFederation(federationArgs, erpPubKeys, activationDelay,
-            erpRedeemScriptBuilder, NON_STANDARD_ERP_FEDERATION.getFormatVersion()
+        return new ErpFederation(
+            federationArgs,
+            erpPubKeys,
+            activationDelay,
+            erpRedeemScriptBuilder,
+            NON_STANDARD_ERP_FEDERATION.getFormatVersion()
         );
     }
 
-    public static ErpFederation buildP2shErpFederation(FederationArgs federationArgs,
-                                                       List<BtcECKey> erpPubKeys,
-                                                       long activationDelay) {
-        ErpRedeemScriptBuilder erpRedeemScriptBuilder = new P2shErpRedeemScriptBuilder();
+    public static ErpFederation buildP2shErpFederation(
+        FederationArgs federationArgs,
+        List<BtcECKey> erpPubKeys,
+        long activationDelay
+    ) {
+        ErpRedeemScriptBuilder erpRedeemScriptBuilder = P2shErpRedeemScriptBuilder.builder();
 
-        return new ErpFederation(federationArgs, erpPubKeys, activationDelay,
-            erpRedeemScriptBuilder, P2SH_ERP_FEDERATION.getFormatVersion());
+        return new ErpFederation(
+            federationArgs,
+            erpPubKeys,
+            activationDelay,
+            erpRedeemScriptBuilder,
+            P2SH_ERP_FEDERATION.getFormatVersion()
+        );
     }
 }
diff --git a/rskj-core/src/test/java/co/rsk/peg/bitcoin/FlyoverRedeemScriptBuilderImplTest.java b/rskj-core/src/test/java/co/rsk/peg/bitcoin/FlyoverRedeemScriptBuilderImplTest.java
new file mode 100644
index 00000000000..1151f921cce
--- /dev/null
+++ b/rskj-core/src/test/java/co/rsk/peg/bitcoin/FlyoverRedeemScriptBuilderImplTest.java
@@ -0,0 +1,75 @@
+package co.rsk.peg.bitcoin;
+
+import static co.rsk.peg.bitcoin.RedeemScriptCreationException.Reason.INVALID_FLYOVER_DERIVATION_HASH;
+import static org.junit.jupiter.api.Assertions.*;
+
+import co.rsk.bitcoinj.script.Script;
+import co.rsk.bitcoinj.script.ScriptChunk;
+import co.rsk.bitcoinj.script.ScriptOpCodes;
+import co.rsk.crypto.Keccak256;
+import co.rsk.peg.federation.Federation;
+import co.rsk.peg.federation.P2shErpFederationBuilder;
+import java.util.List;
+import java.util.stream.Stream;
+import org.ethereum.TestUtils;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class FlyoverRedeemScriptBuilderImplTest {
+    private Script redeemScript;
+    private FlyoverRedeemScriptBuilder flyoverRedeemScriptBuilder;
+
+    @BeforeEach
+    void setUp() {
+        Federation federation = P2shErpFederationBuilder.builder().build();
+        redeemScript = federation.getRedeemScript();
+        flyoverRedeemScriptBuilder = FlyoverRedeemScriptBuilderImpl.builder();
+    }
+
+    @ParameterizedTest
+    @MethodSource("invalidDerivationHashArgsProvider")
+    void addFlyoverDerivationHashToRedeemScript_withInvalidPrefix_shouldThrowFlyoverRedeemScriptCreationException(Keccak256 flyoverDerivationHash) {
+        RedeemScriptCreationException exception = assertThrows(
+            RedeemScriptCreationException.class,
+            () -> flyoverRedeemScriptBuilder.of(flyoverDerivationHash, redeemScript)
+        );
+
+        assertEquals(INVALID_FLYOVER_DERIVATION_HASH, exception.getReason());
+
+        String expectedMessage = String.format("Provided flyover derivation hash %s is invalid.", flyoverDerivationHash);
+        assertEquals(expectedMessage, exception.getMessage());
+    }
+
+    private static Stream<Keccak256> invalidDerivationHashArgsProvider() {
+        return Stream.of(null, Keccak256.ZERO_HASH);
+    }
+
+    @Test
+    void addFlyoverDerivationHashToRedeemScript_shouldReturnRedeemScriptWithFlyoverDerivationHash() {
+        // arrange
+        Keccak256 flyoverDerivationHash = TestUtils.generateHash("hash");
+
+        // act
+        Script redeemScriptWithFlyoverDerivationHash = flyoverRedeemScriptBuilder.of(flyoverDerivationHash, redeemScript);
+
+        // assert
+        List<ScriptChunk> originalRedeemScriptChunks = getOriginalRedeemScriptChunks(redeemScriptWithFlyoverDerivationHash);
+        assertEquals(redeemScript.getChunks(), originalRedeemScriptChunks);
+
+        List<ScriptChunk> redeemScriptWithFlyoverDerivationHashChunks = redeemScriptWithFlyoverDerivationHash.getChunks();
+        ScriptChunk flyoverDerivationHashChunk = redeemScriptWithFlyoverDerivationHashChunks.get(0);
+        ScriptChunk opDropChunk = redeemScriptWithFlyoverDerivationHashChunks.get(1);
+        assertArrayEquals(flyoverDerivationHash.getBytes(), flyoverDerivationHashChunk.data);
+        assertEquals(ScriptOpCodes.OP_DROP, opDropChunk.opcode);
+    }
+
+    private List<ScriptChunk> getOriginalRedeemScriptChunks(Script redeemScript) {
+        List<ScriptChunk> redeemScriptChunks = redeemScript.getChunks();
+        int firstOriginalChunkIndex = 2;
+        int lastOriginalChunkIndex = redeemScriptChunks.size();
+
+        return redeemScriptChunks.subList(firstOriginalChunkIndex, lastOriginalChunkIndex);
+    }
+}
diff --git a/rskj-core/src/test/java/co/rsk/peg/federation/NonStandardErpFederationsTest.java b/rskj-core/src/test/java/co/rsk/peg/federation/NonStandardErpFederationsTest.java
index 9df323cdfe0..e4ecb7b4daa 100644
--- a/rskj-core/src/test/java/co/rsk/peg/federation/NonStandardErpFederationsTest.java
+++ b/rskj-core/src/test/java/co/rsk/peg/federation/NonStandardErpFederationsTest.java
@@ -1,10 +1,10 @@
 package co.rsk.peg.federation;
 
 import static co.rsk.bitcoinj.script.Script.MAX_SCRIPT_ELEMENT_SIZE;
-import static co.rsk.peg.federation.ErpFederationCreationException.Reason.NULL_OR_EMPTY_EMERGENCY_KEYS;
-import static co.rsk.peg.federation.ErpFederationCreationException.Reason.REDEEM_SCRIPT_CREATION_FAILED;
 import static co.rsk.peg.bitcoin.RedeemScriptCreationException.Reason.INVALID_CSV_VALUE;
 import static co.rsk.peg.bitcoin.ScriptCreationException.Reason.ABOVE_MAX_SCRIPT_ELEMENT_SIZE;
+import static co.rsk.peg.federation.ErpFederationCreationException.Reason.NULL_OR_EMPTY_EMERGENCY_KEYS;
+import static co.rsk.peg.federation.ErpFederationCreationException.Reason.REDEEM_SCRIPT_CREATION_FAILED;
 import static org.junit.jupiter.api.Assertions.*;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
@@ -13,9 +13,7 @@
 import co.rsk.bitcoinj.script.Script;
 import co.rsk.bitcoinj.script.ScriptOpCodes;
 import co.rsk.peg.bitcoin.*;
-import co.rsk.peg.federation.constants.FederationConstants;
-import co.rsk.peg.federation.constants.FederationMainNetConstants;
-import co.rsk.peg.federation.constants.FederationTestNetConstants;
+import co.rsk.peg.federation.constants.*;
 import co.rsk.peg.resources.TestConstants;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
@@ -27,10 +25,7 @@
 import java.time.Instant;
 import java.time.ZonedDateTime;
 import java.time.temporal.ChronoUnit;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
+import java.util.*;
 import java.util.stream.Collectors;
 import org.bouncycastle.util.encoders.Hex;
 import org.ethereum.config.blockchain.upgrades.ActivationConfig;
@@ -116,23 +111,27 @@ void createFederation_withOneErpKey_valid() {
         emergencyKeys = Collections.singletonList(emergencyKeys.get(0));
         emergencyThreshold = emergencyKeys.size() / 2 + 1;
 
-        ErpRedeemScriptBuilder builder = new NonStandardErpRedeemScriptBuilder();
-        assertDoesNotThrow(() -> builder
-            .createRedeemScriptFromKeys(
-                defaultKeys, defaultThreshold,
-                emergencyKeys, emergencyThreshold,
-                activationDelayValue));
+        assertDoesNotThrow(() -> NonStandardErpRedeemScriptBuilder.builder().of(
+            defaultKeys,
+            defaultThreshold,
+            emergencyKeys,
+            emergencyThreshold,
+            activationDelayValue
+        ));
     }
 
     @ParameterizedTest
     @ValueSource(ints = {-100, 0})
     void createFederation_withInvalidThresholdValues_throwsIllegalArgumentException(int threshold) {
-        ErpRedeemScriptBuilder builder = new NonStandardErpRedeemScriptBuilder();
-        assertThrows(IllegalArgumentException.class,
-            () -> builder.createRedeemScriptFromKeys(
-                defaultKeys, threshold,
-                emergencyKeys, emergencyThreshold,
-                activationDelayValue)
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> NonStandardErpRedeemScriptBuilder.builder().of(
+                defaultKeys,
+                threshold,
+                emergencyKeys,
+                emergencyThreshold,
+                activationDelayValue
+            )
         );
     }
 
@@ -140,12 +139,15 @@ void createFederation_withInvalidThresholdValues_throwsIllegalArgumentException(
     void createFederation_withThresholdAboveDefaultKeysSize_throwsIllegalArgumentException() {
         int defaultThresholdAboveDefaultKeysSize = defaultKeys.size() + 1;
 
-        ErpRedeemScriptBuilder builder = new NonStandardErpRedeemScriptBuilder();
-        assertThrows(IllegalArgumentException.class,
-            () -> builder.createRedeemScriptFromKeys(
-                defaultKeys, defaultThresholdAboveDefaultKeysSize,
-                emergencyKeys, emergencyThreshold,
-                activationDelayValue)
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> NonStandardErpRedeemScriptBuilder.builder().of(
+                defaultKeys,
+                defaultThresholdAboveDefaultKeysSize,
+                emergencyKeys,
+                emergencyThreshold,
+                activationDelayValue
+            )
         );
     }
 
@@ -197,7 +199,7 @@ void createFederation_postRSKIP293_withInvalidCsvValues_throwsErpFederationCreat
         ErpRedeemScriptBuilder builder = nonStandardErpFederation.getErpRedeemScriptBuilder();
         RedeemScriptCreationException exception = assertThrows(
             RedeemScriptCreationException.class,
-            () -> builder.createRedeemScriptFromKeys(
+            () -> builder.of(
                 defaultKeys, defaultThreshold,
                 emergencyKeys, emergencyThreshold,
                 activationDelayValue)
@@ -215,10 +217,15 @@ void createFederation_withRedeemScriptSizeAboveMaximum_throwsScriptCreationExcep
         newDefaultKeys.add(federator10PublicKey);
         defaultKeys = newDefaultKeys;
 
-        ErpRedeemScriptBuilder builder = new NonStandardErpRedeemScriptBuilder();
         ScriptCreationException exception = assertThrows(
             ScriptCreationException.class,
-            () -> builder.createRedeemScriptFromKeys(defaultKeys, defaultThreshold, emergencyKeys, emergencyThreshold, activationDelayValue)
+            () -> NonStandardErpRedeemScriptBuilder.builder().of(
+                defaultKeys,
+                defaultThreshold,
+                emergencyKeys,
+                emergencyThreshold,
+                activationDelayValue
+            )
         );
         assertEquals(ABOVE_MAX_SCRIPT_ELEMENT_SIZE, exception.getReason());
     }
@@ -244,11 +251,18 @@ void testEquals_basic() {
 
     @Test
     void testEquals_same() {
-        FederationArgs federationArgs =
-            new FederationArgs(nonStandardErpFederation.getMembers(), nonStandardErpFederation.getCreationTime(),
-                nonStandardErpFederation.getCreationBlockNumber(), nonStandardErpFederation.getBtcParams());
-        ErpFederation otherFederation =
-            FederationFactory.buildNonStandardErpFederation(federationArgs, nonStandardErpFederation.getErpPubKeys(), nonStandardErpFederation.getActivationDelay(), activations);
+        FederationArgs federationArgs = new FederationArgs(
+            nonStandardErpFederation.getMembers(),
+            nonStandardErpFederation.getCreationTime(),
+            nonStandardErpFederation.getCreationBlockNumber(),
+            nonStandardErpFederation.getBtcParams()
+        );
+        ErpFederation otherFederation = FederationFactory.buildNonStandardErpFederation(
+            federationArgs,
+            nonStandardErpFederation.getErpPubKeys(),
+            nonStandardErpFederation.getActivationDelay(),
+            activations
+        );
 
         assertEquals(nonStandardErpFederation, otherFederation);
     }
@@ -260,7 +274,12 @@ void federationArgs_from_values_equals_federationArgs_from_nonStandardErpFederat
         long creationBlockNumber = nonStandardErpFederation.getCreationBlockNumber();
         NetworkParameters btcParams = nonStandardErpFederation.getBtcParams();
 
-        FederationArgs federationArgsFromValues = new FederationArgs(federationMembers, creationTime, creationBlockNumber, btcParams);
+        FederationArgs federationArgsFromValues = new FederationArgs(
+            federationMembers,
+            creationTime,
+            creationBlockNumber,
+            btcParams
+        );
         FederationArgs federationArgs = nonStandardErpFederation.getArgs();
 
         assertEquals(federationArgs, federationArgsFromValues);
@@ -269,30 +288,48 @@ void federationArgs_from_values_equals_federationArgs_from_nonStandardErpFederat
     @Test
     void nonStandardErpFederation_from_federationArgs_and_erp_values_equals_nonStandardErpFederation() {
         FederationArgs federationArgs = nonStandardErpFederation.getArgs();
-        ErpFederation nonStandardErpFederationFromFederationArgs =
-            FederationFactory.buildNonStandardErpFederation(federationArgs, emergencyKeys, activationDelayValue, activations);
+        ErpFederation nonStandardErpFederationFromFederationArgs = FederationFactory.buildNonStandardErpFederation(
+            federationArgs,
+            emergencyKeys,
+            activationDelayValue,
+            activations
+        );
 
         assertEquals(nonStandardErpFederation, nonStandardErpFederationFromFederationArgs);
     }
 
     @Test
     void testEquals_differentCreationTime() {
-        FederationArgs federationArgs = new FederationArgs(nonStandardErpFederation.getMembers(), nonStandardErpFederation.getCreationTime().plus(1, ChronoUnit.MILLIS),
-            nonStandardErpFederation.getCreationBlockNumber(), nonStandardErpFederation.getBtcParams()
+        FederationArgs federationArgs = new FederationArgs(
+            nonStandardErpFederation.getMembers(),
+            nonStandardErpFederation.getCreationTime().plus(1, ChronoUnit.MILLIS),
+            nonStandardErpFederation.getCreationBlockNumber(),
+            nonStandardErpFederation.getBtcParams()
+        );
+        ErpFederation otherFederation = FederationFactory.buildNonStandardErpFederation(
+            federationArgs,
+            nonStandardErpFederation.getErpPubKeys(),
+            nonStandardErpFederation.getActivationDelay(),
+            activations
         );
-        ErpFederation otherFederation =
-            FederationFactory.buildNonStandardErpFederation(federationArgs, nonStandardErpFederation.getErpPubKeys(), nonStandardErpFederation.getActivationDelay(), activations);
 
         assertEquals(nonStandardErpFederation, otherFederation);
     }
 
     @Test
     void testEquals_differentCreationBlockNumber() {
-        FederationArgs federationArgs = new FederationArgs(nonStandardErpFederation.getMembers(),
-            nonStandardErpFederation.getCreationTime(), nonStandardErpFederation.getCreationBlockNumber() + 1,
-            nonStandardErpFederation.getBtcParams());
-        ErpFederation otherFederation =
-            FederationFactory.buildNonStandardErpFederation(federationArgs, nonStandardErpFederation.getErpPubKeys(), nonStandardErpFederation.getActivationDelay(), activations);
+        FederationArgs federationArgs = new FederationArgs(
+            nonStandardErpFederation.getMembers(),
+            nonStandardErpFederation.getCreationTime(),
+            nonStandardErpFederation.getCreationBlockNumber() + 1,
+            nonStandardErpFederation.getBtcParams()
+        );
+        ErpFederation otherFederation = FederationFactory.buildNonStandardErpFederation(
+            federationArgs,
+            nonStandardErpFederation.getErpPubKeys(),
+            nonStandardErpFederation.getActivationDelay(),
+            activations
+        );
 
         assertEquals(nonStandardErpFederation, otherFederation);
     }
@@ -302,7 +339,7 @@ void testEquals_differentNetworkParameters() {
         networkParameters = NetworkParameters.fromID(NetworkParameters.ID_REGTEST);
 
         ErpFederation otherFederation = createDefaultNonStandardErpFederation();
-        Assertions.assertNotEquals(nonStandardErpFederation, otherFederation);
+        assertNotEquals(nonStandardErpFederation, otherFederation);
     }
 
     @Test
@@ -313,7 +350,7 @@ void testEquals_differentNumberOfMembers() {
         defaultKeys = newDefaultKeys;
 
         ErpFederation otherFederation = createDefaultNonStandardErpFederation();
-        Assertions.assertNotEquals(nonStandardErpFederation, otherFederation);
+        assertNotEquals(nonStandardErpFederation, otherFederation);
     }
 
     @Test
@@ -328,7 +365,7 @@ void testEquals_differentMembers() {
         defaultKeys = newDefaultKeys;
 
         ErpFederation otherFederation = createDefaultNonStandardErpFederation();
-        Assertions.assertNotEquals(nonStandardErpFederation, otherFederation);
+        assertNotEquals(nonStandardErpFederation, otherFederation);
     }
 
     @Test
@@ -337,22 +374,43 @@ void createdRedeemScriptProgramFromNonStandardErpBuilderHardcoded_withRealValues
             Hex.decode("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");
 
         // these values belong to the non-standard hardcoded fed
-        BtcECKey federator0PublicKey = BtcECKey.fromPublicOnly(Hex.decode("0208f40073a9e43b3e9103acec79767a6de9b0409749884e989960fee578012fce"));
-        BtcECKey federator1PublicKey = BtcECKey.fromPublicOnly(Hex.decode("0225e892391625854128c5c4ea4340de0c2a70570f33db53426fc9c746597a03f4"));
-        BtcECKey federator2PublicKey = BtcECKey.fromPublicOnly(Hex.decode("025a2f522aea776fab5241ad72f7f05918e8606676461cb6ce38265a52d4ca9ed6"));
-        BtcECKey federator3PublicKey = BtcECKey.fromPublicOnly(Hex.decode("02afc230c2d355b1a577682b07bc2646041b5d0177af0f98395a46018da699b6da"));
-        BtcECKey federator4PublicKey = BtcECKey.fromPublicOnly(Hex.decode("039a060badbeb24bee49eb2063f616c0f0f0765d4ca646b20a88ce828f259fcdb9"));
+        BtcECKey federator0PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("0208f40073a9e43b3e9103acec79767a6de9b0409749884e989960fee578012fce")
+        );
+        BtcECKey federator1PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("0225e892391625854128c5c4ea4340de0c2a70570f33db53426fc9c746597a03f4")
+        );
+        BtcECKey federator2PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("025a2f522aea776fab5241ad72f7f05918e8606676461cb6ce38265a52d4ca9ed6")
+        );
+        BtcECKey federator3PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("02afc230c2d355b1a577682b07bc2646041b5d0177af0f98395a46018da699b6da")
+        );
+        BtcECKey federator4PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("039a060badbeb24bee49eb2063f616c0f0f0765d4ca646b20a88ce828f259fcdb9")
+        );
         defaultKeys = Arrays.asList(
-            federator0PublicKey, federator1PublicKey, federator2PublicKey,
-            federator3PublicKey, federator4PublicKey
+            federator0PublicKey,
+            federator1PublicKey,
+            federator2PublicKey,
+            federator3PublicKey,
+            federator4PublicKey
         );
         defaultThreshold = defaultKeys.size() / 2 + 1;
 
-        BtcECKey emergency0PublicKey = BtcECKey.fromPublicOnly(Hex.decode("0216c23b2ea8e4f11c3f9e22711addb1d16a93964796913830856b568cc3ea21d3"));
-        BtcECKey emergency1PublicKey = BtcECKey.fromPublicOnly(Hex.decode("0275562901dd8faae20de0a4166362a4f82188db77dbed4ca887422ea1ec185f14"));
-        BtcECKey emergency2PublicKey = BtcECKey.fromPublicOnly(Hex.decode("034db69f2112f4fb1bb6141bf6e2bd6631f0484d0bd95b16767902c9fe219d4a6f"));
+        BtcECKey emergency0PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("0216c23b2ea8e4f11c3f9e22711addb1d16a93964796913830856b568cc3ea21d3")
+        );
+        BtcECKey emergency1PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("0275562901dd8faae20de0a4166362a4f82188db77dbed4ca887422ea1ec185f14")
+        );
+        BtcECKey emergency2PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("034db69f2112f4fb1bb6141bf6e2bd6631f0484d0bd95b16767902c9fe219d4a6f")
+        );
         emergencyKeys = Arrays.asList(
-            emergency0PublicKey, emergency1PublicKey, emergency2PublicKey
+            emergency0PublicKey,
+            emergency1PublicKey,
+            emergency2PublicKey
         );
         emergencyThreshold = emergencyKeys.size() / 2 + 1;
         activationDelayValue = 52_560L;
@@ -364,11 +422,14 @@ void createdRedeemScriptProgramFromNonStandardErpBuilderHardcoded_withRealValues
         nonStandardErpFederation = createDefaultNonStandardErpFederation();
 
         ErpRedeemScriptBuilder builder = nonStandardErpFederation.getErpRedeemScriptBuilder();
-        Script obtainedRedeemScript = builder
-            .createRedeemScriptFromKeys(defaultKeys, defaultThreshold,
-                emergencyKeys, emergencyThreshold,
-                activationDelayValue
-            );
+        Script obtainedRedeemScript = builder.of(
+            defaultKeys,
+            defaultThreshold,
+            emergencyKeys,
+            emergencyThreshold,
+            activationDelayValue
+        );
+
         assertArrayEquals(expectedRedeemScriptProgram, obtainedRedeemScript.getProgram());
     }
 
@@ -378,22 +439,43 @@ void createdRedeemScriptProgramFromNonStandardErpBuilderCsvUnsignedBE_withRealVa
             Hex.decode("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");
 
         // these values belong to the non-standard csv unsigned be fed
-        BtcECKey federator0PublicKey = BtcECKey.fromPublicOnly(Hex.decode("0208f40073a9e43b3e9103acec79767a6de9b0409749884e989960fee578012fce"));
-        BtcECKey federator1PublicKey = BtcECKey.fromPublicOnly(Hex.decode("0225e892391625854128c5c4ea4340de0c2a70570f33db53426fc9c746597a03f4"));
-        BtcECKey federator2PublicKey = BtcECKey.fromPublicOnly(Hex.decode("025a2f522aea776fab5241ad72f7f05918e8606676461cb6ce38265a52d4ca9ed6"));
-        BtcECKey federator3PublicKey = BtcECKey.fromPublicOnly(Hex.decode("02afc230c2d355b1a577682b07bc2646041b5d0177af0f98395a46018da699b6da"));
-        BtcECKey federator4PublicKey = BtcECKey.fromPublicOnly(Hex.decode("0344a3c38cd59afcba3edcebe143e025574594b001700dec41e59409bdbd0f2a09"));
+        BtcECKey federator0PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("0208f40073a9e43b3e9103acec79767a6de9b0409749884e989960fee578012fce")
+        );
+        BtcECKey federator1PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("0225e892391625854128c5c4ea4340de0c2a70570f33db53426fc9c746597a03f4")
+        );
+        BtcECKey federator2PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("025a2f522aea776fab5241ad72f7f05918e8606676461cb6ce38265a52d4ca9ed6")
+        );
+        BtcECKey federator3PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("02afc230c2d355b1a577682b07bc2646041b5d0177af0f98395a46018da699b6da")
+        );
+        BtcECKey federator4PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("0344a3c38cd59afcba3edcebe143e025574594b001700dec41e59409bdbd0f2a09")
+        );
         defaultKeys = Arrays.asList(
-            federator0PublicKey, federator1PublicKey, federator2PublicKey,
-            federator3PublicKey, federator4PublicKey
+            federator0PublicKey,
+            federator1PublicKey,
+            federator2PublicKey,
+            federator3PublicKey,
+            federator4PublicKey
         );
         defaultThreshold = defaultKeys.size() / 2 + 1;
 
-        BtcECKey emergency0PublicKey = BtcECKey.fromPublicOnly(Hex.decode("0216c23b2ea8e4f11c3f9e22711addb1d16a93964796913830856b568cc3ea21d3"));
-        BtcECKey emergency1PublicKey = BtcECKey.fromPublicOnly(Hex.decode("0275562901dd8faae20de0a4166362a4f82188db77dbed4ca887422ea1ec185f14"));
-        BtcECKey emergency2PublicKey = BtcECKey.fromPublicOnly(Hex.decode("034db69f2112f4fb1bb6141bf6e2bd6631f0484d0bd95b16767902c9fe219d4a6f"));
+        BtcECKey emergency0PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("0216c23b2ea8e4f11c3f9e22711addb1d16a93964796913830856b568cc3ea21d3")
+        );
+        BtcECKey emergency1PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("0275562901dd8faae20de0a4166362a4f82188db77dbed4ca887422ea1ec185f14")
+        );
+        BtcECKey emergency2PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("034db69f2112f4fb1bb6141bf6e2bd6631f0484d0bd95b16767902c9fe219d4a6f")
+        );
         emergencyKeys = Arrays.asList(
-            emergency0PublicKey, emergency1PublicKey, emergency2PublicKey
+            emergency0PublicKey,
+            emergency1PublicKey,
+            emergency2PublicKey
         );
         emergencyThreshold = emergencyKeys.size() / 2 + 1;
         activationDelayValue = 52_560L;
@@ -405,12 +487,14 @@ void createdRedeemScriptProgramFromNonStandardErpBuilderCsvUnsignedBE_withRealVa
         nonStandardErpFederation = createDefaultNonStandardErpFederation();
 
         ErpRedeemScriptBuilder builder = nonStandardErpFederation.getErpRedeemScriptBuilder();
-        Script obtainedRedeemScript = builder
-            .createRedeemScriptFromKeys(
-                defaultKeys, defaultThreshold,
-                emergencyKeys, emergencyThreshold,
-                activationDelayValue
-            );
+        Script obtainedRedeemScript = builder.of(
+            defaultKeys,
+            defaultThreshold,
+            emergencyKeys,
+            emergencyThreshold,
+            activationDelayValue
+        );
+
         assertArrayEquals(expectedRedeemScriptProgram, obtainedRedeemScript.getProgram());
     }
 
@@ -420,22 +504,43 @@ void createdRedeemScriptProgramFromNonStandardErpBuilder_withRealValues_equalsRe
             Hex.decode("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");
 
         // these values belong to the non-standard fed
-        BtcECKey federator0PublicKey = BtcECKey.fromPublicOnly(Hex.decode("0208f40073a9e43b3e9103acec79767a6de9b0409749884e989960fee578012fce"));
-        BtcECKey federator1PublicKey = BtcECKey.fromPublicOnly(Hex.decode("0225e892391625854128c5c4ea4340de0c2a70570f33db53426fc9c746597a03f4"));
-        BtcECKey federator2PublicKey = BtcECKey.fromPublicOnly(Hex.decode("025a2f522aea776fab5241ad72f7f05918e8606676461cb6ce38265a52d4ca9ed6"));
-        BtcECKey federator3PublicKey = BtcECKey.fromPublicOnly(Hex.decode("02afc230c2d355b1a577682b07bc2646041b5d0177af0f98395a46018da699b6da"));
-        BtcECKey federator4PublicKey = BtcECKey.fromPublicOnly(Hex.decode("03fb8e1d5d0392d35ca8c3656acb6193dbf392b3e89b9b7b86693f5c80f7ce8581"));
+        BtcECKey federator0PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("0208f40073a9e43b3e9103acec79767a6de9b0409749884e989960fee578012fce")
+        );
+        BtcECKey federator1PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("0225e892391625854128c5c4ea4340de0c2a70570f33db53426fc9c746597a03f4")
+        );
+        BtcECKey federator2PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("025a2f522aea776fab5241ad72f7f05918e8606676461cb6ce38265a52d4ca9ed6")
+        );
+        BtcECKey federator3PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("02afc230c2d355b1a577682b07bc2646041b5d0177af0f98395a46018da699b6da")
+        );
+        BtcECKey federator4PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("03fb8e1d5d0392d35ca8c3656acb6193dbf392b3e89b9b7b86693f5c80f7ce8581")
+        );
         defaultKeys = Arrays.asList(
-            federator0PublicKey, federator1PublicKey, federator2PublicKey,
-            federator3PublicKey, federator4PublicKey
+            federator0PublicKey,
+            federator1PublicKey,
+            federator2PublicKey,
+            federator3PublicKey,
+            federator4PublicKey
         );
         defaultThreshold = defaultKeys.size() / 2 + 1;
 
-        BtcECKey emergency0PublicKey = BtcECKey.fromPublicOnly(Hex.decode("0216c23b2ea8e4f11c3f9e22711addb1d16a93964796913830856b568cc3ea21d3"));
-        BtcECKey emergency1PublicKey = BtcECKey.fromPublicOnly(Hex.decode("0275562901dd8faae20de0a4166362a4f82188db77dbed4ca887422ea1ec185f14"));
-        BtcECKey emergency2PublicKey = BtcECKey.fromPublicOnly(Hex.decode("034db69f2112f4fb1bb6141bf6e2bd6631f0484d0bd95b16767902c9fe219d4a6f"));
+        BtcECKey emergency0PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("0216c23b2ea8e4f11c3f9e22711addb1d16a93964796913830856b568cc3ea21d3")
+        );
+        BtcECKey emergency1PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("0275562901dd8faae20de0a4166362a4f82188db77dbed4ca887422ea1ec185f14")
+        );
+        BtcECKey emergency2PublicKey = BtcECKey.fromPublicOnly(
+            Hex.decode("034db69f2112f4fb1bb6141bf6e2bd6631f0484d0bd95b16767902c9fe219d4a6f")
+        );
         emergencyKeys = Arrays.asList(
-            emergency0PublicKey, emergency1PublicKey, emergency2PublicKey
+            emergency0PublicKey,
+            emergency1PublicKey,
+            emergency2PublicKey
         );
         emergencyThreshold = emergencyKeys.size() / 2 + 1;
         activationDelayValue = 52_560L;
@@ -448,11 +553,14 @@ void createdRedeemScriptProgramFromNonStandardErpBuilder_withRealValues_equalsRe
         nonStandardErpFederation = createDefaultNonStandardErpFederation();
 
         ErpRedeemScriptBuilder builder = nonStandardErpFederation.getErpRedeemScriptBuilder();
-        Script obtainedRedeemScript = builder
-            .createRedeemScriptFromKeys(defaultKeys, defaultThreshold,
-                emergencyKeys, emergencyThreshold,
-                activationDelayValue
-            );
+        Script obtainedRedeemScript = builder.of(
+            defaultKeys,
+            defaultThreshold,
+            emergencyKeys,
+            emergencyThreshold,
+            activationDelayValue
+        );
+
         assertArrayEquals(expectedRedeemScriptProgram, obtainedRedeemScript.getProgram());
     }
 
@@ -490,8 +598,7 @@ void createdFederationInfo_withRealValues_equalsExistingFederationInfo_testnet()
     @Test
     void getErpPubKeys_fromUncompressedPublicKeys_equals() {
         // Public keys used for creating nonStandardErpFederation, but uncompressed format now
-        emergencyKeys = emergencyKeys
-            .stream()
+        emergencyKeys = emergencyKeys.stream()
             .map(BtcECKey::decompress)
             .collect(Collectors.toList());
 
@@ -568,7 +675,7 @@ void getRedeemScript_changes_related_to_RSKIP293_testnet() {
         nonStandardErpFederation = createDefaultNonStandardErpFederation();
         Script postRskip293RedeemScript = nonStandardErpFederation.getRedeemScript();
 
-        Assertions.assertNotEquals(preRskip293RedeemScript, postRskip293RedeemScript);
+        assertNotEquals(preRskip293RedeemScript, postRskip293RedeemScript);
     }
 
     @Test
@@ -616,7 +723,7 @@ void getRedeemScript_before_RSKIP_284_mainnet() {
         when(activations.isActive(ConsensusRule.RSKIP284)).thenReturn(false);
         nonStandardErpFederation = createDefaultNonStandardErpFederation();
 
-        Assertions.assertNotEquals(TestConstants.ERP_TESTNET_REDEEM_SCRIPT, nonStandardErpFederation.getRedeemScript());
+        assertNotEquals(TestConstants.ERP_TESTNET_REDEEM_SCRIPT, nonStandardErpFederation.getRedeemScript());
         validateErpRedeemScript(
             nonStandardErpFederation.getRedeemScript(),
             activationDelayValue
@@ -647,7 +754,7 @@ void getRedeemScript_after_RSKIP_201_before_RSKIP_293_mainnet() {
         // check the hardcoded fed didnt exist on mainnet after rskip201
         nonStandardErpFederation = createDefaultNonStandardErpFederation();
         builder = nonStandardErpFederation.getErpRedeemScriptBuilder();
-        Assertions.assertNotEquals(TestConstants.ERP_TESTNET_REDEEM_SCRIPT, nonStandardErpFederation.getRedeemScript());
+        assertNotEquals(TestConstants.ERP_TESTNET_REDEEM_SCRIPT, nonStandardErpFederation.getRedeemScript());
         assertFalse(builder instanceof NonStandardErpRedeemScriptBuilderHardcoded);
 
         // check the hardcoded fed didnt exist on mainnet after rskip284
@@ -721,13 +828,12 @@ void spendFromNonStandardErpFed_before_RSKIP293_testnet_using_erp_multisig_can_s
         // The CSV value defined in BridgeTestnetConstants,
         // actually allows the emergency multisig to spend before the expected amount of blocks
         // Since it's encoded as BE and decoded as LE, the result is a number lower than the one defined in the constant
-        assertDoesNotThrow(() ->
-            spendFromNonStandardErpFed(
-                federationTestNetConstants.getBtcParams(),
-                federationTestNetConstants.getErpFedActivationDelay(),
-                false,
-                true
-            ));
+        assertDoesNotThrow(() -> spendFromNonStandardErpFed(
+            federationTestNetConstants.getBtcParams(),
+            federationTestNetConstants.getErpFedActivationDelay(),
+            false,
+            true
+        ));
     }
 
     @Test
diff --git a/rskj-core/src/test/java/co/rsk/peg/federation/P2shErpFederationTest.java b/rskj-core/src/test/java/co/rsk/peg/federation/P2shErpFederationTest.java
index 8a5b6549052..b38aa4121d4 100644
--- a/rskj-core/src/test/java/co/rsk/peg/federation/P2shErpFederationTest.java
+++ b/rskj-core/src/test/java/co/rsk/peg/federation/P2shErpFederationTest.java
@@ -11,10 +11,7 @@
 import co.rsk.bitcoinj.script.Script;
 import co.rsk.bitcoinj.script.ScriptOpCodes;
 import co.rsk.peg.bitcoin.*;
-import co.rsk.peg.constants.BridgeConstants;
-import co.rsk.peg.constants.BridgeMainNetConstants;
-import co.rsk.peg.constants.BridgeRegTestConstants;
-import co.rsk.peg.constants.BridgeTestNetConstants;
+import co.rsk.peg.constants.*;
 import co.rsk.peg.federation.constants.FederationConstants;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
@@ -132,12 +129,15 @@ void createFederation_withOneErpKey_valid() {
     @ParameterizedTest
     @ValueSource(ints = {-100, 0})
     void createFederation_withInvalidThresholdValues_throwsIllegalArgumentException(int threshold) {
-        ErpRedeemScriptBuilder builder = new P2shErpRedeemScriptBuilder();
-        assertThrows(IllegalArgumentException.class,
-            () -> builder.createRedeemScriptFromKeys(
-                defaultKeys, threshold,
-                emergencyKeys, emergencyThreshold,
-                activationDelayValue)
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> P2shErpRedeemScriptBuilder.builder().of(
+                defaultKeys,
+                threshold,
+                emergencyKeys,
+                emergencyThreshold,
+                activationDelayValue
+            )
         );
     }
 
@@ -145,12 +145,15 @@ void createFederation_withInvalidThresholdValues_throwsIllegalArgumentException(
     void createFederation_withThresholdAboveDefaultKeysSize_throwsIllegalArgumentException() {
         int defaultThresholdAboveDefaultKeysSize = defaultKeys.size() + 1;
 
-        ErpRedeemScriptBuilder builder = new P2shErpRedeemScriptBuilder();
-        assertThrows(IllegalArgumentException.class,
-            () -> builder.createRedeemScriptFromKeys(
-                defaultKeys, defaultThresholdAboveDefaultKeysSize,
-                emergencyKeys, emergencyThreshold,
-                activationDelayValue)
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> P2shErpRedeemScriptBuilder.builder().of(
+                defaultKeys,
+                defaultThresholdAboveDefaultKeysSize,
+                emergencyKeys,
+                emergencyThreshold,
+                activationDelayValue
+            )
         );
     }
 
@@ -170,18 +173,23 @@ void createFederation_invalidCsvValues_throwsErpFederationCreationException(long
         federation = createDefaultP2shErpFederation();
         ErpFederationCreationException fedException = assertThrows(
             ErpFederationCreationException.class,
-            () -> federation.getRedeemScript());
+            () -> federation.getRedeemScript()
+        );
         assertEquals(REDEEM_SCRIPT_CREATION_FAILED, fedException.getReason());
 
         // Check the builder throws the particular expected exception
         ErpRedeemScriptBuilder builder = federation.getErpRedeemScriptBuilder();
         RedeemScriptCreationException builderException = assertThrows(
             RedeemScriptCreationException.class,
-            () -> builder.createRedeemScriptFromKeys(
-                defaultKeys, defaultThreshold,
-                emergencyKeys, emergencyThreshold,
+            () -> builder.of(
+                defaultKeys,
+                defaultThreshold,
+                emergencyKeys,
+                emergencyThreshold,
                 activationDelayValue
-            ));
+            )
+        );
+
         assertEquals(INVALID_CSV_VALUE, builderException.getReason());
     }
 
@@ -198,11 +206,14 @@ void createFederation_withRedeemScriptSizeAboveMaximum_throwsScriptCreationExcep
         ErpRedeemScriptBuilder builder = federation.getErpRedeemScriptBuilder();
         ScriptCreationException exception = assertThrows(
             ScriptCreationException.class,
-            () -> builder.createRedeemScriptFromKeys(
-                defaultKeys, defaultThreshold,
-                emergencyKeys, emergencyThreshold,
+            () -> builder.of(
+                defaultKeys,
+                defaultThreshold,
+                emergencyKeys,
+                emergencyThreshold,
                 activationDelayValue
-            ));
+            )
+        );
         assertEquals(ABOVE_MAX_SCRIPT_ELEMENT_SIZE, exception.getReason());
     }
 
@@ -220,17 +231,24 @@ void getActivationDelay() {
     void testEquals_basic() {
         assertEquals(federation, federation);
 
-        Assertions.assertNotEquals(null, federation);
-        Assertions.assertNotEquals(federation, new Object());
-        Assertions.assertNotEquals("something else", federation);
+        assertNotEquals(null, federation);
+        assertNotEquals(federation, new Object());
+        assertNotEquals("something else", federation);
     }
 
     @Test
     void testEquals_same() {
-        FederationArgs federationArgs = new FederationArgs(federation.getMembers(), federation.getCreationTime(),
-            federation.getCreationBlockNumber(), federation.getBtcParams());
-        ErpFederation otherFederation =
-            FederationFactory.buildP2shErpFederation(federationArgs, federation.getErpPubKeys(), federation.getActivationDelay());
+        FederationArgs federationArgs = new FederationArgs(
+            federation.getMembers(),
+            federation.getCreationTime(),
+            federation.getCreationBlockNumber(),
+            federation.getBtcParams()
+        );
+        ErpFederation otherFederation = FederationFactory.buildP2shErpFederation(
+            federationArgs,
+            federation.getErpPubKeys(),
+            federation.getActivationDelay()
+        );
 
         assertEquals(federation, otherFederation);
     }
@@ -242,8 +260,12 @@ void federationArgs_from_values_equals_federationArgs_from_p2shErpFederation() {
         long creationBlockNumber = federation.getCreationBlockNumber();
         NetworkParameters btcParams = federation.getBtcParams();
 
-        FederationArgs federationArgsFromValues =
-            new FederationArgs(federationMembers, creationTime, creationBlockNumber, btcParams);
+        FederationArgs federationArgsFromValues = new FederationArgs(
+            federationMembers,
+            creationTime,
+            creationBlockNumber,
+            btcParams
+        );
         FederationArgs federationArgs = federation.getArgs();
 
         assertEquals(federationArgs, federationArgsFromValues);
@@ -252,8 +274,11 @@ void federationArgs_from_values_equals_federationArgs_from_p2shErpFederation() {
     @Test
     void p2shErpFederation_from_federationArgs_and_erp_values_equals_p2shErpFederation() {
         FederationArgs federationArgs = federation.getArgs();
-        ErpFederation federationFromFederationArgs =
-            FederationFactory.buildP2shErpFederation(federationArgs, emergencyKeys, activationDelayValue);
+        ErpFederation federationFromFederationArgs = FederationFactory.buildP2shErpFederation(
+            federationArgs,
+            emergencyKeys,
+            activationDelayValue
+        );
 
         assertEquals(federation, federationFromFederationArgs);
     }
@@ -266,7 +291,7 @@ void testEquals_differentNumberOfMembers() {
         defaultKeys = newDefaultKeys;
 
         ErpFederation otherFederation = createDefaultP2shErpFederation();
-        Assertions.assertNotEquals(federation, otherFederation);
+        assertNotEquals(federation, otherFederation);
     }
 
     @Test
@@ -274,7 +299,7 @@ void testEquals_differentNetworkParameters() {
         networkParameters = NetworkParameters.fromID(NetworkParameters.ID_REGTEST);
 
         ErpFederation otherFederation = createDefaultP2shErpFederation();
-        Assertions.assertNotEquals(federation, otherFederation);
+        assertNotEquals(federation, otherFederation);
     }
 
     @Test
@@ -289,7 +314,7 @@ void testEquals_differentMembers() {
         defaultKeys = newDefaultKeys;
 
         ErpFederation otherFederation = createDefaultP2shErpFederation();
-        Assertions.assertNotEquals(federation, otherFederation);
+        assertNotEquals(federation, otherFederation);
     }
 
     @Test
@@ -305,8 +330,12 @@ void createdRedeemScriptProgramFromP2shErpBuilder_withRealValues_equalsRealRedee
         BtcECKey federator5PublicKey = BtcECKey.fromPublicOnly(Hex.decode("03db2ebad883823cefe8b2336c03b8d9c6afee4cbac77c7e935bc8c51ec20b2663"));
         BtcECKey federator6PublicKey = BtcECKey.fromPublicOnly(Hex.decode("03fb8e1d5d0392d35ca8c3656acb6193dbf392b3e89b9b7b86693f5c80f7ce8581"));
         defaultKeys = Arrays.asList(
-            federator0PublicKey, federator1PublicKey, federator2PublicKey,
-            federator3PublicKey, federator4PublicKey, federator5PublicKey,
+            federator0PublicKey,
+            federator1PublicKey,
+            federator2PublicKey,
+            federator3PublicKey,
+            federator4PublicKey,
+            federator5PublicKey,
             federator6PublicKey
         );
         defaultThreshold = defaultKeys.size() / 2 + 1;
@@ -315,7 +344,9 @@ void createdRedeemScriptProgramFromP2shErpBuilder_withRealValues_equalsRealRedee
         BtcECKey emergency1PublicKey = BtcECKey.fromPublicOnly(Hex.decode("0275562901dd8faae20de0a4166362a4f82188db77dbed4ca887422ea1ec185f14"));
         BtcECKey emergency2PublicKey = BtcECKey.fromPublicOnly(Hex.decode("034db69f2112f4fb1bb6141bf6e2bd6631f0484d0bd95b16767902c9fe219d4a6f"));
         emergencyKeys = Arrays.asList(
-            emergency0PublicKey, emergency1PublicKey, emergency2PublicKey
+            emergency0PublicKey,
+            emergency1PublicKey,
+            emergency2PublicKey
         );
         emergencyThreshold = emergencyKeys.size() / 2 + 1;
 
@@ -324,12 +355,13 @@ void createdRedeemScriptProgramFromP2shErpBuilder_withRealValues_equalsRealRedee
         createAndValidateFederation();
 
         ErpRedeemScriptBuilder builder = federation.getErpRedeemScriptBuilder();
-        Script obtainedRedeemScript =
-            builder.createRedeemScriptFromKeys(
-                defaultKeys, defaultThreshold,
-                emergencyKeys, emergencyThreshold,
-                activationDelayValue
-            );
+        Script obtainedRedeemScript = builder.of(
+            defaultKeys,
+            defaultThreshold,
+            emergencyKeys,
+            emergencyThreshold,
+            activationDelayValue
+        );
         assertArrayEquals(redeemScriptProgram, obtainedRedeemScript.getProgram());
     }
 
@@ -374,7 +406,7 @@ void getStandardRedeemScript() {
         ErpFederation p2shFed = FederationFactory.buildP2shErpFederation(federationArgs, erpPubKeys, 10_000);
 
         assertEquals(standardMultisigFed.getRedeemScript(), p2shFed.getDefaultRedeemScript());
-        Assertions.assertNotEquals(p2shFed.getRedeemScript(), p2shFed.getDefaultRedeemScript());
+        assertNotEquals(p2shFed.getRedeemScript(), p2shFed.getDefaultRedeemScript());
     }
 
     @Test
@@ -477,11 +509,17 @@ void getErpRedeemScript_compareOtherImplementation_P2SHERPFederation() throws IO
         for (RawGeneratedRedeemScript generatedScript : generatedScripts) {
             // Skip test cases with invalid redeem script that exceed the maximum size
             if (generatedScript.script.getProgram().length <= MAX_SCRIPT_ELEMENT_SIZE) {
-                FederationArgs federationArgs = new FederationArgs(FederationTestUtils.getFederationMembersWithBtcKeys(generatedScript.mainFed),
-                    ZonedDateTime.parse("2017-06-10T02:30:00Z").toInstant(), 1,
-                    NetworkParameters.fromID(NetworkParameters.ID_TESTNET));
-                Federation erpFederation =
-                    FederationFactory.buildP2shErpFederation(federationArgs, generatedScript.emergencyFed, generatedScript.timelock);
+                FederationArgs federationArgs = new FederationArgs(
+                    FederationTestUtils.getFederationMembersWithBtcKeys(generatedScript.mainFed),
+                    ZonedDateTime.parse("2017-06-10T02:30:00Z").toInstant(),
+                    1,
+                    NetworkParameters.fromID(NetworkParameters.ID_TESTNET)
+                );
+                Federation erpFederation = FederationFactory.buildP2shErpFederation(
+                    federationArgs,
+                    generatedScript.emergencyFed,
+                    generatedScript.timelock
+                );
 
                 Script rskjScript = erpFederation.getRedeemScript();
                 Script alternativeScript = generatedScript.script;
@@ -509,9 +547,17 @@ void spendFromP2shErpFed(
             true
         );
 
-        FederationArgs federationArgs =
-            new FederationArgs(federationMembers, creationTime, 0L, networkParameters);
-        ErpFederation p2shErpFed = FederationFactory.buildP2shErpFederation(federationArgs, emergencyKeys, activationDelay);
+        FederationArgs federationArgs = new FederationArgs(
+            federationMembers,
+            creationTime,
+            0L,
+            networkParameters
+        );
+        ErpFederation p2shErpFed = FederationFactory.buildP2shErpFederation(
+            federationArgs,
+            emergencyKeys,
+            activationDelay
+        );
 
         Coin value = Coin.valueOf(1_000_000);
         Coin fee = Coin.valueOf(10_000);