C# encryption shows difference result than Java equivalent

Question

I have a piece of Java code that I need to convert to C#. The original Java code looks like below

    public static String encryptPassword(String pwd, String key) {
        try {
            Security.addProvider(new com.sun.crypto.provider.SunJCE());
            Key secretKey = getDesSecretKey(key);
            Cipher cipher = Cipher.getInstance("DES");
            cipher.init(Cipher.ENCRYPT_MODE, secretKey);
            byte[] data = pwd.getBytes(StandardCharsets.UTF_8);
            byte[] result = cipher.doFinal(data);
            return new sun.misc.BASE64Encoder().encode(result);
        } catch (Exception e) {
            return null;
        }
    }

    public static SecretKey getDesSecretKey(String key) {
        byte[] result = new byte[8];
        byte[] keys;
        keys = key.getBytes(StandardCharsets.UTF_8);
        for (int i = 0; i < 8; i++) {
            if (i < keys.length) {
                result[i] = keys[i];
            } else {
                result[i] = 0x01;
            }
        }
        return new SecretKeySpec(result, "DES");
    }

I converted it to below C# code

    public static string EncryptPassword(string password, string key)
    {
        const int keyLength = 8;
        var bytes = new byte[keyLength];
        var keyBytes = Encoding.UTF8.GetBytes(key);
        for (int i = 0; i < keyLength; i++)
        {
            if (i < keyBytes.Length)
                bytes[i] = keyBytes[i];
            else
                bytes[i] = 0x01;
        }

#pragma warning disable S5547
        using var des = DES.Create();
#pragma warning restore S5547
        des.Key = bytes;
        des.IV = new byte[] { 0, 0, 0, 0, 0, 0, 0, 0 };
#pragma warning disable S3329
        var encryptor = des.CreateEncryptor(des.Key, des.IV);
#pragma warning restore S3329
        var passwordBytes = Encoding.UTF8.GetBytes(password);
        var payload = encryptor.TransformFinalBlock(passwordBytes, 0, passwordBytes.Length);
        
        return Convert.ToBase64String(payload);
    }

For simple cases, it worked fine. Such as password 000000 and key 18823214892, etc. Both Java and C# code give same result. But for a little bit complex case, such as password crmeb.com and key demo, the result differs at the 10th character. Java gives out 7iIl3H5zCinwrYbrxAR7cQ==, but C# shows 7iIl3H5zCikSuWVlZa1dyA==. What have I done wrong? Maybe the des.IV should be initialized differently? Or I have chosen the wrong encryption class?

Below is my test code

var encryptedPassword = CryptoUtils.EncryptPassword("000000", "18823214892");
encryptedPassword.Should().Be("PwePP4OrK2o=");

encryptedPassword = CryptoUtils.EncryptPassword("123456", "admin");
encryptedPassword.Should().Be("L8qdg72wbeQ=");

encryptedPassword = CryptoUtils.EncryptPassword("000000", "18292417675");
encryptedPassword.Should().Be("w9LTrURn7xU=");

encryptedPassword = CryptoUtils.EncryptPassword("crmeb.com", "demo");
encryptedPassword.Should().Be("7iIl3H5zCinwrYbrxAR7cQ==");

The last test case won't pass

BTW, I followed this link to do the conversion. Java equivalent encryption code in .NET

Answer 1

Just found out why. It's because that I didn't set des.Mode, it should be set as below

des.Mode = CipherMode.ECB;

after that, everything works