diff --git a/Sources/KeystoreManager/EthereumKeystoreV3.swift b/Sources/KeystoreManager/EthereumKeystoreV3.swift
index 089b430..b099a85 100644
--- a/Sources/KeystoreManager/EthereumKeystoreV3.swift
+++ b/Sources/KeystoreManager/EthereumKeystoreV3.swift
@@ -173,15 +173,15 @@ public class EthereumKeystoreV3: AbstractKeystore {
         }
         guard let derivedKey = passwordDerivedKey else { return nil }
         var dataForMAC = Data()
-        
-        dataForMAC.append(derivedKey.suffix(16))
+        let derivedKeyLast16bytes = Data(derivedKey[(derivedKey.count - 16) ... (derivedKey.count - 1)])
+        dataForMAC.append(derivedKeyLast16bytes)
         guard let cipherText = Data.fromHex(keystoreParams.crypto.ciphertext) else { return nil }
         if cipherText.count != 32 { return nil }
         dataForMAC.append(cipherText)
         let mac = dataForMAC.sha3(.keccak256)
         guard let calculatedMac = Data.fromHex(keystoreParams.crypto.mac), mac.constantTimeComparisonTo(calculatedMac) else { return nil }
         let cipher = keystoreParams.crypto.cipher
-        let decryptionKey = derivedKey.suffix(16)
+        let decryptionKey = derivedKey[0 ... 15]
         guard let IV = Data.fromHex(keystoreParams.crypto.cipherparams.iv) else { return nil }
         var decryptedPK: Array<UInt8>?
         switch cipher {
diff --git a/Tests/SECP256K1Tests.swift b/Tests/SECP256K1Tests.swift
index 12c546a..7f7e017 100644
--- a/Tests/SECP256K1Tests.swift
+++ b/Tests/SECP256K1Tests.swift
@@ -102,14 +102,17 @@ class SECP256K1Tests: XCTestCase {
     func testSomeSignatures() throws {
         
         let password = "Your password"
-        let keystore = try! BIP32Keystore(mnemonics: Mnemonics(), password: password)
+        let keystore = try! EthereumKeystoreV3(password: password)!
+        let signer = keystore.addresses[0]
         
         for i in 1...3 {
             print("Signing \(i)/10")
             let message = "\(i) Hello World \(i)".data
-            let signature = try! Web3Signer.signPersonalMessage(message, keystore: keystore, account: keystore.addresses[0], password: password)
+            let signature = try! Web3Signer.signPersonalMessage(message, keystore: keystore, account: signer, password: password)
             let address = try! Web3.default.personal.ecrecover(personalMessage: message, signature: signature)
-            XCTAssertEqual(address,keystore.addresses[0])
+            print(address)
+            print(signer)
+            XCTAssertEqual(address,signer)
         }
     }
 }