diff --git a/pkg/ethsigner/transaction.go b/pkg/ethsigner/transaction.go
index eee6e7f..8394033 100644
--- a/pkg/ethsigner/transaction.go
+++ b/pkg/ethsigner/transaction.go
@@ -18,6 +18,7 @@ package ethsigner
 
 import (
 	"encoding/json"
+	"fmt"
 	"math/big"
 
 	"github.com/hyperledger/firefly-signer/pkg/ethtypes"
@@ -96,7 +97,10 @@ func (t *Transaction) Build1559(chainID int64) rlp.List {
 // - If either of the new EIP-1559 fields are set, use EIP-1559
 // - By default use EIP-155 signing
 // Never picks legacy-legacy (non EIP-155), or EIP-2930
-func (t *Transaction) Sign(signer *secp256k1.KeyPair, chainID int64) ([]byte, error) {
+func (t *Transaction) Sign(signer secp256k1.Signer, chainID int64) ([]byte, error) {
+	if signer == nil {
+		return nil, fmt.Errorf("invalid signer")
+	}
 	if t.MaxPriorityFeePerGas.BigInt().Sign() > 0 || t.MaxFeePerGas.BigInt().Sign() > 0 {
 		return t.SignEIP1559(signer, chainID)
 	}
@@ -124,7 +128,10 @@ func (t *Transaction) SignaturePayloadLegacyOriginal() *TransactionSignaturePayl
 }
 
 // SignLegacyOriginal uses legacy transaction structure, with legacy V value (27/28)
-func (t *Transaction) SignLegacyOriginal(signer *secp256k1.KeyPair) ([]byte, error) {
+func (t *Transaction) SignLegacyOriginal(signer secp256k1.Signer) ([]byte, error) {
+	if signer == nil {
+		return nil, fmt.Errorf("invalid signer")
+	}
 	signatureData := t.SignaturePayloadLegacyOriginal()
 	sig, err := signer.Sign(signatureData.data)
 	if err != nil {
@@ -148,7 +155,10 @@ func (t *Transaction) SignaturePayloadLegacyEIP155(chainID int64) *TransactionSi
 }
 
 // SignLegacyEIP155 uses legacy transaction structure, with EIP-155 signing V value (2*ChainID + 35 + Y-parity)
-func (t *Transaction) SignLegacyEIP155(signer *secp256k1.KeyPair, chainID int64) ([]byte, error) {
+func (t *Transaction) SignLegacyEIP155(signer secp256k1.Signer, chainID int64) ([]byte, error) {
+	if signer == nil {
+		return nil, fmt.Errorf("invalid signer")
+	}
 
 	signaturePayload := t.SignaturePayloadLegacyEIP155(chainID)
 
@@ -178,7 +188,10 @@ func (t *Transaction) SignaturePayloadEIP1559(chainID int64) *TransactionSignatu
 }
 
 // SignEIP1559 uses EIP-1559 transaction structure (with EIP-2718 transaction type byte), with EIP-2930 V value (0 / 1 - direct parity-Y)
-func (t *Transaction) SignEIP1559(signer *secp256k1.KeyPair, chainID int64) ([]byte, error) {
+func (t *Transaction) SignEIP1559(signer secp256k1.Signer, chainID int64) ([]byte, error) {
+	if signer == nil {
+		return nil, fmt.Errorf("invalid signer")
+	}
 
 	signaturePayload := t.SignaturePayloadEIP1559(chainID)
 	sig, err := signer.Sign(signaturePayload.data)
diff --git a/pkg/secp256k1/keypair.go b/pkg/secp256k1/keypair.go
index 8839038..2099ed5 100644
--- a/pkg/secp256k1/keypair.go
+++ b/pkg/secp256k1/keypair.go
@@ -35,7 +35,7 @@ func (k *KeyPair) PrivateKeyBytes() []byte {
 }
 
 func (k *KeyPair) PublicKeyBytes() []byte {
-	// Remove the "04" Suffix byte when computing the address. This byte indicates that it is an uncompressed public key.
+	// Remove the "04" Prefix byte when computing the address. This byte indicates that it is an uncompressed public key.
 	return k.PublicKey.SerializeUncompressed()[1:]
 }
 
diff --git a/pkg/secp256k1/signer.go b/pkg/secp256k1/signer.go
index 1d93602..998560e 100644
--- a/pkg/secp256k1/signer.go
+++ b/pkg/secp256k1/signer.go
@@ -31,6 +31,11 @@ type SignatureData struct {
 	S *big.Int
 }
 
+// Signer is the low level common interface that can be implemented by any module which provides signature capability
+type Signer interface {
+	Sign(message []byte) (*SignatureData, error)
+}
+
 // getVNormalized returns the original 27/28 parity
 func (s *SignatureData) getVNormalized(chainID int64) (byte, error) {
 	v := s.V.Int64()