/// <summary>
/// Decrypt string with Rijndael.
/// </summary>
/// <param name="cipherText"></param>
/// <param name="passPhrase"></param>
/// <param name="keysize"></param>
/// <returns></returns>
public static string DecryptStringManual(string cipherText, string passPhrase, int keysize)
{
using (PasswordDeriveBytes password = new PasswordDeriveBytes(passPhrase, Encoding.UTF8.GetBytes(ClassUtils.FromHex(passPhrase.Substring(0, 8)))))
{
byte[] keyBytes = password.GetBytes(keysize / 8);
using (var symmetricKey = new AesCryptoServiceProvider()
{
Mode = CipherMode.CFB
})
{
byte[] initVectorBytes = password.GetBytes(16);
symmetricKey.BlockSize = 128;
symmetricKey.KeySize = keysize;
symmetricKey.Padding = PaddingMode.PKCS7;
symmetricKey.Key = keyBytes;
using (ICryptoTransform decryptor = symmetricKey.CreateDecryptor(keyBytes, initVectorBytes))
{
byte[] cipherTextBytes = Convert.FromBase64String(cipherText);
using (MemoryStream memoryStream = new MemoryStream(cipherTextBytes))
{
using (CryptoStream cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))
{
byte[] plainTextBytes = new byte[cipherTextBytes.Length];
int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
return(Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount));
}
}
}
}
}
}
/// <summary>
/// Encrypt string from Rijndael.
/// </summary>
/// <param name="plainText"></param>
/// <param name="passPhrase"></param>
/// <param name="keysize"></param>
/// <returns></returns>
public static string EncryptStringManual(string plainText, string passPhrase, int keysize)
{
using (PasswordDeriveBytes password = new PasswordDeriveBytes(passPhrase, Encoding.UTF8.GetBytes(ClassUtils.FromHex(passPhrase.Substring(0, 8)))))
{
byte[] keyBytes = password.GetBytes(keysize / 8);
using (var symmetricKey = new AesCryptoServiceProvider()
{
Mode = CipherMode.CFB
})
{
byte[] initVectorBytes = password.GetBytes(16);
symmetricKey.BlockSize = 128;
symmetricKey.KeySize = keysize;
symmetricKey.Padding = PaddingMode.PKCS7;
symmetricKey.Key = keyBytes;
using (ICryptoTransform encryptor = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes))
{
using (MemoryStream memoryStream = new MemoryStream())
{
using (CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
{
byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
cryptoStream.FlushFinalBlock();
byte[] cipherTextBytes = memoryStream.ToArray();
return(Convert.ToBase64String(cipherTextBytes));
}
}
}
}
}
}
