Transform Java AES Decryption Code to CryptoSwift

Question

I have a problem with transforming Java Code to Swift for AES Encryption with CBC. Here is the Java Code:

public static String decryptOAuthClientSecret(String cipher) {
        String result = "";
        try {
            Cipher aes = Cipher.getInstance("AES/CBC/PKCS5Padding");
            byte[] sec = MessageDigest.getInstance("MD5").digest(SECRET.getBytes());
            SecretKeySpec skeySpec = new SecretKeySpec(sec, "AES");
            AlgorithmParameterSpec spec = new IvParameterSpec(sec);
            aes.init(Cipher.DECRYPT_MODE, skeySpec, spec);
            result = new String(aes.doFinal(Base64Utils.decodeFromString(new String(cipher.getBytes()))));
        } catch (Exception e) {
        }
        return result;
    }

My Swift Code:

import CryptoSwift

func decryptAES(cipher: String) {
    let spec = SECRET.md5()
    let iv = String(spec.prefix(16))
    do {
        let aes = try AES(key: spec.bytes, blockMode: CBC(iv: iv.bytes), padding: .pkcs5)
        let result = try aes.decrypt(Data(base64Encoded: cipher)!.bytes)
        print(result.toHexString())
        print(String(bytes: result, encoding: .ascii))
    } catch(let error) {
        print(error)
    }
}

Test:

SECRET: asdfasdfasdfasdf

CIPHER: 3+pTpRej59qOjbLz9oP5fN05lHbrT7Gybk9wPA58pXrXAYp2jsO4HchHczvmT4RBvA9pR6Ve/PCe3WEYxSaOqg==

RESULT: 2d2dac4e768eb53498ffd0ebfeef2840f81eb09e2d0f06f8

ACTUAL HEX RESULT: 7e56cfb3bf4f6be7b13aa398e0f2478194f15059d3b795815569b469247eca894b1d44ca2786e1952523ba8cc6618d1da4660a359f767047efd4ec538c6df2fd

ACTUAL ASCII RESULT: ~Vϳ¿Okç±:£àòGñPYÓ·Ui´i$~ÊK\u{1D}DÊ\'á%#ºÆa\u{1D}¤f\n5vpGïÔìSmòý

And here the JavaTest:

@Test
    public void testDecryptOAuthClientSecret() {
        String decryptedSecret = CryptoUtils.decryptOAuthClientSecret("3+pTpRej59qOjbLz9oP5fN05lHbrT7Gybk9wPA58pXrXAYp2jsO4HchHczvmT4RBvA9pR6Ve/PCe3WEYxSaOqg==");
        assertEquals("2d2dac4e768eb53498ffd0ebfeef2840f81eb09e2d0f06f8", decryptedSecret);
    }

Does anybody know what im doing wrong?

EDIT:

For the complete clarification here is the encryption function in Java and the clearText:

public static String encryptOAuthClientSecret(String plain) {
        String result = "";
        try {
            Cipher aes = Cipher.getInstance("AES/CBC/PKCS5Padding");
            byte[] sec = MessageDigest.getInstance("MD5").digest(SECRET.getBytes());
            SecretKeySpec skeySpec = new SecretKeySpec(sec, "AES");
            AlgorithmParameterSpec spec = new IvParameterSpec(sec);
            aes.init(Cipher.ENCRYPT_MODE, skeySpec, spec);
            result = Base64Utils.encodeToString(aes.doFinal(plain.getBytes()));
        } catch (Exception e) {
        }
        return result;
    }

And the test case:

@Test
    public void testEncryptOAuthClientSecret() {
        String encryptedSecret = CryptoUtils.encryptOAuthClientSecret("2d2dac4e768eb53498ffd0ebfeef2840f81eb09e2d0f06f8");
        assertEquals("3+pTpRej59qOjbLz9oP5fN05lHbrT7Gybk9wPA58pXrXAYp2jsO4HchHczvmT4RBvA9pR6Ve/PCe3WEYxSaOqg==", encryptedSecret);
    }

Answer 1

Use base64 String instead of hexString.

extension String {

func encrypt(key : String ,value : String) -> String {
    var result = ""
    do {
        let key: [UInt8] = Array(key.utf8) as [UInt8]
        let value : [UInt8] = Array(value.utf8) as [UInt8]
        let aes = try! AES(key: key, blockMode: CBC(iv: value) as BlockMode, padding: .pkcs7)
        let encrypted = try aes.encrypt(Array(self.utf8))
        result = encrypted.toBase64() ?? ""
    } catch {
        print("Error: \(error)")
    }
    return result
}

// decrypt the string
func decrypt(key : String ,value : String) -> String {
    var result = ""
    do {
        let encrypted = self
        let key: [UInt8] = Array(key.utf8) as [UInt8]
        let value : [UInt8] = Array(value.utf8) as [UInt8]
        let aes = try! AES(key: key, blockMode: CBC(iv: value) as BlockMode, padding: .pkcs7)
        let decrypted = try aes.decrypt(Array(base64: encrypted))
        result = String(data: Data(decrypted), encoding: .utf8) ?? ""
    } catch {
        print("Error: \(error)")
    }
    return result
}
}

For testing you can you can use. Key bits 256. key - "ABC2587@3878avd5DEF3698@4989bwe6" value - "1234567890123456"

Hope it's helps to you.