Question

Only part of the string is getting decrypted, i think it has to do with my encoding.

Here is what happens:

        string s = "The brown fox jumped over the green frog";
        string k = "urieurut";
        string enc = EncryptString(s, k);
        string dec = DecryptString(enc, k);

The RESULT is this: The brown fox juϼ㴘裴혽Ή⪻ㆉr th≸ g⟤een frog

public static string EncryptString(string stringToEncrypt, string encryptionKey)
{
    string encrypted = String.Empty;

    UnicodeEncoding UE = new UnicodeEncoding();
    byte[] key = UE.GetBytes(encryptionKey);

    RijndaelManaged RMCrypto = new RijndaelManaged();
    MemoryStream ms = new MemoryStream();
    CryptoStream cs = new CryptoStream(ms, RMCrypto.CreateEncryptor(key, key), CryptoStreamMode.Write);

    byte[] encryptedString = UE.GetBytes(stringToEncrypt);
    cs.Write(encryptedString, 0, encryptedString.Length);
    cs.FlushFinalBlock();
    cs.Close();

    encrypted = UE.GetString(ms.ToArray());
    return encrypted;
}

public static string DecryptString(string stringToDecrypt, string encryptionKey)
{
    string decrypted = String.Empty;

    UnicodeEncoding UE = new UnicodeEncoding();
    byte[] key = UE.GetBytes(encryptionKey);
    byte[] data = UE.GetBytes(stringToDecrypt);

    RijndaelManaged RMCrypto = new RijndaelManaged();
    MemoryStream ms = new MemoryStream();
    CryptoStream cs = new CryptoStream(ms, RMCrypto.CreateDecryptor(key, key), CryptoStreamMode.Write);
    cs.Write(data, 0, data.Length);
    cs.FlushFinalBlock();
    cs.Close();

    decrypted = UE.GetString(ms.ToArray());

    return decrypted;
}

Answer 1

I solved my issue by using base64 string for the encryption – i may look at other options but i only needed these methods for a small amount of data, here is the final code:

public static string EncryptString(string stringToEncrypt, string encryptionKey)
{
    string encrypted = String.Empty;
    byte[] key = Encoding.Unicode.GetBytes(encryptionKey);

    RijndaelManaged RMCrypto = new RijndaelManaged();
    RMCrypto.Padding = PaddingMode.PKCS7;
    MemoryStream ms = new MemoryStream();
    CryptoStream cs = new CryptoStream(ms, RMCrypto.CreateEncryptor(key, key), CryptoStreamMode.Write);

    byte[] encryptedString = Encoding.ASCII.GetBytes(stringToEncrypt);
    cs.Write(encryptedString, 0, encryptedString.Length);
    cs.FlushFinalBlock();
    cs.Close();

    //encrypted = Encoding.ASCII.GetString(ms.ToArray());
    return Convert.ToBase64String(ms.ToArray());
}

public static string DecryptString(string stringToDecrypt, string encryptionKey)
{
    string decrypted = String.Empty;
    byte[] key = Encoding.Unicode.GetBytes(encryptionKey);
    byte[] data = Convert.FromBase64String(stringToDecrypt);

    RijndaelManaged RMCrypto = new RijndaelManaged();
    RMCrypto.Padding = PaddingMode.PKCS7;
    MemoryStream ms = new MemoryStream();
    CryptoStream cs = new CryptoStream(ms, RMCrypto.CreateDecryptor(key, key), CryptoStreamMode.Write);
    cs.Write(data, 0, data.Length);
    cs.FlushFinalBlock();
    cs.Close();

    decrypted = Encoding.ASCII.GetString(ms.ToArray());

    return decrypted;
}