diff --git a/anychain-core/Cargo.toml b/anychain-core/Cargo.toml
index f0aaa80..06bf194 100644
--- a/anychain-core/Cargo.toml
+++ b/anychain-core/Cargo.toml
@@ -23,12 +23,6 @@ base58 = { workspace = true , optional = true }
 rand_core = { workspace = true }
 serde_json = { workspace = true }
 sha2 = { workspace = true }
-# rand = { workspace = true }
-# ethereum-types = { workspace = true }
-# blake2b_simd = { workspace = true }
-# libsecp256k1 = { workspace = true }
-# bls-signatures = { workspace = true }
-# rlp = { workspace = true }
 
 [features]
 default = ["std"]
diff --git a/anychain-core/src/address.rs b/anychain-core/src/address.rs
index 22cddc2..000fb56 100644
--- a/anychain-core/src/address.rs
+++ b/anychain-core/src/address.rs
@@ -1,10 +1,11 @@
-use crate::format::Format;
-use crate::no_std::*;
-use crate::public_key::{PublicKey, PublicKeyError};
-use core::{
-    fmt::{Debug, Display},
-    hash::Hash,
-    str::FromStr,
+use crate::{
+    format::Format,
+    no_std::{
+        fmt::{Debug, Display},
+        hash::Hash,
+        FromStr, String,
+    },
+    public_key::{PublicKey, PublicKeyError},
 };
 
 /// The interface for a generic address.
diff --git a/anychain-core/src/amount.rs b/anychain-core/src/amount.rs
index 2bfbaa4..d883a29 100644
--- a/anychain-core/src/amount.rs
+++ b/anychain-core/src/amount.rs
@@ -1,7 +1,10 @@
-use crate::no_std::*;
-use core::{
-    fmt::{Debug, Display},
-    hash::Hash,
+use {
+    crate::no_std::{
+        fmt::{Debug, Display},
+        hash::Hash,
+        String,
+    },
+    thiserror::Error,
 };
 
 /// The interface for a generic amount.
diff --git a/anychain-core/src/error.rs b/anychain-core/src/error.rs
index 0e2bccd..5e1d444 100644
--- a/anychain-core/src/error.rs
+++ b/anychain-core/src/error.rs
@@ -1,8 +1,10 @@
-use crate::AddressError;
-use crate::AmountError;
-use crate::FormatError;
-use crate::PublicKeyError;
-use crate::TransactionError;
+use crate::{
+    no_std::{
+        fmt::Error as FmtError, io::Error as IoError, num::ParseIntError as NumParseIntError,
+        String,
+    },
+    AddressError, AmountError, FormatError, PublicKeyError, TransactionError,
+};
 
 #[derive(Debug, Error)]
 pub enum Error {
@@ -25,14 +27,14 @@ pub enum Error {
     InvalidFormat(#[from] FormatError),
 
     #[error("io error: {0:}")]
-    Io(#[from] ::std::io::Error),
+    Io(#[from] IoError),
 
     #[error("fmt error: {0:}")]
-    Fmt(#[from] ::std::fmt::Error),
+    Fmt(#[from] FmtError),
 
     #[error("fromHex error: {0:}")]
     FromHex(#[from] ::hex::FromHexError),
 
     #[error("parsing error: {0:}")]
-    ParseInt(#[from] ::std::num::ParseIntError),
+    ParseInt(#[from] NumParseIntError),
 }
diff --git a/anychain-core/src/format.rs b/anychain-core/src/format.rs
index 724a457..66886a1 100644
--- a/anychain-core/src/format.rs
+++ b/anychain-core/src/format.rs
@@ -1,7 +1,10 @@
-use crate::no_std::*;
-use core::{
-    fmt::{Debug, Display},
-    hash::Hash,
+use {
+    crate::no_std::{
+        fmt::{Debug, Display},
+        hash::Hash,
+        String, Vec,
+    },
+    thiserror::Error,
 };
 
 /// The interface for a generic format.
diff --git a/anychain-core/src/network.rs b/anychain-core/src/network.rs
index 81e882e..5b968e9 100644
--- a/anychain-core/src/network.rs
+++ b/anychain-core/src/network.rs
@@ -1,8 +1,10 @@
-use crate::no_std::*;
-use core::{
-    fmt::{Debug, Display},
-    hash::Hash,
-    str::FromStr,
+use {
+    crate::no_std::{
+        fmt::{Debug, Display},
+        hash::Hash,
+        FromStr, String,
+    },
+    thiserror::Error,
 };
 
 /// The interface for a generic network.
@@ -12,7 +14,7 @@ pub trait Network:
     const NAME: &'static str;
 }
 
-#[derive(Debug, thiserror::Error)]
+#[derive(Debug, Error)]
 pub enum NetworkError {
     #[error("invalid extended private key prefix: {0}")]
     InvalidExtendedPrivateKeyPrefix(String),
diff --git a/anychain-core/src/no_std/mod.rs b/anychain-core/src/no_std/mod.rs
index 6564857..6c1e569 100644
--- a/anychain-core/src/no_std/mod.rs
+++ b/anychain-core/src/no_std/mod.rs
@@ -4,10 +4,18 @@ pub use alloc::{
     borrow::ToOwned, format, string::FromUtf8Error, string::String, string::ToString, vec, vec::Vec,
 };
 
+#[cfg(not(feature = "std"))]
+#[doc(hidden)]
+pub use core::{
+    hash, num,
+    {fmt, str::FromStr},
+};
+
 #[cfg(feature = "std")]
 #[doc(hidden)]
 pub use std::{
-    borrow::ToOwned, format, string::FromUtf8Error, string::String, string::ToString, vec, vec::Vec,
+    borrow::ToOwned, fmt, format, hash, num, str::FromStr, string::FromUtf8Error, string::String,
+    string::ToString, vec, vec::Vec,
 };
 
 #[cfg(not(feature = "std"))]
diff --git a/anychain-core/src/public_key.rs b/anychain-core/src/public_key.rs
index bfd78af..30dcfec 100644
--- a/anychain-core/src/public_key.rs
+++ b/anychain-core/src/public_key.rs
@@ -1,9 +1,13 @@
-use crate::address::{Address, AddressError};
-use crate::format::Format;
-use crate::no_std::*;
-use core::{
-    fmt::{Debug, Display},
-    str::FromStr,
+use {
+    crate::{
+        address::{Address, AddressError},
+        format::Format,
+        no_std::{
+            fmt::{Debug, Display},
+            FromStr, String,
+        },
+    },
+    thiserror::Error,
 };
 
 /// Generic public key.
diff --git a/anychain-core/src/transaction.rs b/anychain-core/src/transaction.rs
index 4d8cda7..8816751 100644
--- a/anychain-core/src/transaction.rs
+++ b/anychain-core/src/transaction.rs
@@ -1,12 +1,17 @@
-use crate::address::{Address, AddressError};
-use crate::amount::AmountError;
-use crate::format::Format;
-use crate::no_std::*;
-use crate::public_key::PublicKey;
-use crate::utilities::crypto::keccak256;
-use core::{
-    fmt::{Debug, Display},
-    hash::Hash,
+use {
+    crate::{
+        address::{Address, AddressError},
+        amount::AmountError,
+        format::Format,
+        no_std::{
+            fmt::{Debug, Display},
+            hash::Hash,
+            String, Vec,
+        },
+        public_key::PublicKey,
+        utilities::crypto::keccak256,
+    },
+    thiserror::Error,
 };
 
 /**
@@ -48,7 +53,7 @@ pub trait Transaction: Clone + Send + Sync + 'static {
     fn to_transaction_id(&self) -> Result<Self::TransactionId, TransactionError>;
 }
 
-#[derive(Debug, thiserror::Error)]
+#[derive(Debug, Error)]
 pub enum TransactionError {
     #[error("{0}")]
     AddressError(#[from] AddressError),