diff --git a/web3.js/src/secp256k1-program.js b/web3.js/src/secp256k1-program.js
index 86e7429134..ed27c2a09d 100644
--- a/web3.js/src/secp256k1-program.js
+++ b/web3.js/src/secp256k1-program.js
@@ -13,7 +13,7 @@ import {toBuffer} from './util/to-buffer';
 const {publicKeyCreate, ecdsaSign} = secp256k1;
 
 const PRIVATE_KEY_BYTES = 32;
-const PUBLIC_KEY_BYTES = 65;
+const PUBLIC_KEY_BYTES = 64;
 const HASHED_PUBKEY_SERIALIZED_SIZE = 20;
 const SIGNATURE_OFFSETS_SERIALIZED_SIZE = 11;
 
@@ -52,7 +52,7 @@ const SECP256K1_INSTRUCTION_LAYOUT = BufferLayout.struct([
   BufferLayout.u16('messageDataOffset'),
   BufferLayout.u16('messageDataSize'),
   BufferLayout.u8('messageInstructionIndex'),
-  BufferLayout.blob(20, 'ethPublicKey'),
+  BufferLayout.blob(20, 'ethAddress'),
   BufferLayout.blob(64, 'signature'),
   BufferLayout.u8('recoveryId'),
 ]);
@@ -78,16 +78,16 @@ export class Secp256k1Program {
       `Public key must be ${PUBLIC_KEY_BYTES} bytes`,
     );
 
-    let ethPublicKey;
+    let ethAddress;
     try {
-      ethPublicKey = constructEthPubkey(publicKey);
+      ethAddress = constructEthAddress(publicKey);
     } catch (error) {
       throw new Error(`Error constructing ethereum public key: ${error}`);
     }
 
     const dataStart = 1 + SIGNATURE_OFFSETS_SERIALIZED_SIZE;
     const ethAddressOffset = dataStart;
-    const signatureOffset = dataStart + ethPublicKey.length;
+    const signatureOffset = dataStart + ethAddress.length;
     const messageDataOffset = signatureOffset + signature.length + 1;
     const numSignatures = 1;
 
@@ -97,17 +97,17 @@ export class Secp256k1Program {
 
     SECP256K1_INSTRUCTION_LAYOUT.encode(
       {
-        numSignatures: numSignatures,
-        signatureOffset: signatureOffset,
+        numSignatures,
+        signatureOffset,
         signatureInstructionIndex: 0,
-        ethAddressOffset: ethAddressOffset,
+        ethAddressOffset,
         ethAddressInstructionIndex: 0,
-        messageDataOffset: messageDataOffset,
+        messageDataOffset,
         messageDataSize: message.length,
         messageInstructionIndex: 0,
         signature: toBuffer(signature),
-        ethPublicKey: ethPublicKey,
-        recoveryId: recoveryId,
+        ethAddress,
+        recoveryId,
       },
       instructionData,
     );
@@ -135,7 +135,7 @@ export class Secp256k1Program {
     );
 
     try {
-      const publicKey = publicKeyCreate(privateKey, false);
+      const publicKey = publicKeyCreate(privateKey, false).slice(1); // throw away leading byte
       const messageHash = Buffer.from(
         keccak_256.update(toBuffer(message)).digest(),
       );
@@ -153,12 +153,10 @@ export class Secp256k1Program {
   }
 }
 
-function constructEthPubkey(
+function constructEthAddress(
   publicKey: Buffer | Uint8Array | Array<number>,
 ): Buffer {
-  return Buffer.from(
-    keccak_256
-      .update(toBuffer(publicKey.slice(1))) // throw away leading byte
-      .digest(),
-  ).slice(-HASHED_PUBKEY_SERIALIZED_SIZE);
+  return Buffer.from(keccak_256.update(toBuffer(publicKey)).digest()).slice(
+    -HASHED_PUBKEY_SERIALIZED_SIZE,
+  );
 }
diff --git a/web3.js/test/secp256k1-program.test.js b/web3.js/test/secp256k1-program.test.js
index cca55d03d5..76215e0f29 100644
--- a/web3.js/test/secp256k1-program.test.js
+++ b/web3.js/test/secp256k1-program.test.js
@@ -27,7 +27,7 @@ if (process.env.TEST_LIVE) {
   describe('secp256k1', () => {
     it('create secp256k1 instruction with public key', async () => {
       const privateKey = randomPrivateKey();
-      const publicKey = publicKeyCreate(privateKey, false);
+      const publicKey = publicKeyCreate(privateKey, false).slice(1);
       const message = Buffer.from('This is a message');
       const messageHash = Buffer.from(
         keccak_256.update(toBuffer(message)).digest(),