fix(weaver): usage of weak PRNG issue

The Logic Behind the Problem
When RNG (Random Number Generator) values are not received through a hardware TRNG, seed values apply a certain pattern. (It takes a seed value such as a mathematical formula or time.) In response to this situation, there are various secure random classes to increase security.

Solution
Changes have been made to get random values using safe randomness instead of mathematical randomness. This increases the complexity of the pattern, making it difficult to discover even if data is listened to for long periods of time.

The changes that have been made;
- In the certificate_utils.go file, the random value was taken from the math class (mrand math/rand) and used. By taking this random value from the secure random class, we obtain a more reliable random value. I added HmacGenerate and generateSecureRandomKey functions for readability and ease of use. If you want to generate a key again, the generateSecureRandomKey function, which uses secure random, can be used.

- In HashFunctions.kt, kotlin.random.Random class has been replaced with the more reliable java.security.SecureRandom class.

- The reason for the change in eciesCrypto.js is that the length of aes-128-ctr is not considered reliable by various standards. For this reason, I preferred the more reliable 256 length.

Fixes hyperledger-cacti#2765

Signed-off-by: Kağan Can Şit <[email protected]>

weaver/core/network/fabric-interop-cc/contracts/interop/certificate_utils.go

@@ -21,7 +21,6 @@ import (
 	"fmt"
 	"hash"
 	"math/big"
-	mrand "math/rand"
 	"time"
 
 	"golang.org/x/crypto/ed25519"
@@ -207,7 +206,7 @@ func ecdsaVerify(verKey *ecdsa.PublicKey, msgHash, signature []byte) error {
 	return nil
 }
 
-//Validate Ed25519 signature
+// Validate Ed25519 signature
 func verifyEd25519Signature(pubKey []byte, hashedMessage []byte, signature []byte) error {
 
 	result := ed25519.Verify(pubKey, hashedMessage, signature)
@@ -297,12 +296,31 @@ func encryptWithEd25519PublicKey(message []byte, pubKey []byte) ([]byte, error)
 	return []byte(""), nil
 }
 
+func generateSecureRandomKey(length int) ([]byte, error) {
+	key := make([]byte, length)
+	_, err := rand.Read(key)
+	if err != nil {
+		return nil, err
+	}
+	return key, nil
+}
+
+func generateHMAC(data, key []byte) ([]byte, error) {
+	hmacHash := hmac.New(sha256.New, key)
+	_, err := hmacHash.Write(data)
+	if err != nil {
+		return nil, err
+	}
+	return hmacHash.Sum(nil), nil
+}
+
 func generateConfidentialInteropPayloadAndHash(message []byte, cert string) ([]byte, error) {
 	// Generate a 16-byte random key for the HMAC
-	hashKey := make([]byte, 16)
-	for i := 0; i < 16 ; i++ {
-		hashKey[i] = byte(mrand.Intn(255))
+	hashKey, err := generateSecureRandomKey(16)
+	if err != nil {
+		return []byte(""), err
 	}
+
 	confidentialPayloadContents := common.ConfidentialPayloadContents{
 		Payload: message,
 		Random: hashKey,
@@ -311,22 +329,26 @@ func generateConfidentialInteropPayloadAndHash(message []byte, cert string) ([]b
 	if err != nil {
 		return []byte(""), err
 	}
+
 	x509Cert, err := parseCert(cert)
 	if err != nil {
 		return []byte(""), err
 	}
+
 	encryptedPayload, err := encryptWithCert(confidentialPayloadContentsBytes, x509Cert)
 	if err != nil {
 		return []byte(""), err
 	}
 
-	payloadHMAC := hmac.New(sha256.New, hashKey)
-	payloadHMAC.Write(message)
-	payloadHMACBytes := payloadHMAC.Sum(nil)
+	payloadHMAC, err := generateHMAC(message, hashKey)
+	if err != nil {
+		return []byte(""), err
+	}
+
 	confidentialPayload := common.ConfidentialPayload{
 		EncryptedPayload: encryptedPayload,
 		HashType: common.ConfidentialPayload_HMAC,
-		Hash: payloadHMACBytes,
+		Hash: payloadHMAC,
 	}
 	confidentialPayloadBytes, err := proto.Marshal(&confidentialPayload)
 	if err != nil {

weaver/sdks/corda/src/main/kotlin/org/hyperledger/cacti/weaver/sdk/corda/HashFunctions.kt

@@ -9,7 +9,7 @@ package org.hyperledger.cacti.weaver.sdk.corda;
 import java.util.Base64
 import net.corda.core.utilities.OpaqueBytes
 import net.corda.core.crypto.sha256
-import kotlin.random.Random
+import java.security.SecureRandom
 import org.hyperledger.cacti.weaver.protos.common.asset_locks.AssetLocks.HashMechanism
 import org.hyperledger.cacti.weaver.imodule.corda.states.sha512
 
@@ -42,8 +42,9 @@ class HashFunctions {
 
         override fun generateRandomPreimage(length: Int)
         {
-            val bytes = ByteArray(length)
-            Random.nextBytes(bytes)
+            val secureRandom = SecureRandom.getInstanceStrong();
+            val bytes = ByteArray(length);
+            secureRandom.nextBytes(bytes);
             this.setPreimage(Base64.getEncoder().encodeToString(bytes));
         }
         override fun setPreimage(preImage: String) {

weaver/sdks/fabric/interoperation-node-sdk/src/eciesCrypto.js

@@ -161,7 +161,7 @@ function eciesEncryptMessage(recipientPublicKey, msg, options) {
     const hKm = bitsToBytes(hmacKeyHash.finalize());
 
     const iv = crypto.randomBytes(IVLength);
-    const cipher = crypto.createCipheriv("aes-128-ctr", Buffer.from(aesKey), iv);
+    const cipher = crypto.createCipheriv("aes-256-ctr", Buffer.from(aesKey), iv);
     const encryptedBytes = cipher.update(msg);
     const EM = Buffer.concat([iv, encryptedBytes]);
     const D = hmac(hKm, EM, options);