Specified key is not a valid size for this algorithm
C#EncryptionRijndaelmanagedC# Problem Overview
I have with this code:
RijndaelManaged rijndaelCipher = new RijndaelManaged();
// Set key and IV
rijndaelCipher.Key = Convert.FromBase64String("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz012345678912");
rijndaelCipher.IV = Convert.FromBase64String("1234567890123456789012345678901234567890123456789012345678901234");
I get throws :
Specified key is not a valid size for this algorithm.
Specified initialization vector (IV) does not match the block size for this algorithm.
What's wrong with this strings ? Can I count at some examples strings from You ?
C# Solutions
Solution 1 - C#
The string "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz012345678912" when base64-decoded yields 48 bytes (384 bits). RijndaelManaged supports 128, 192 and 256 bit keys.
A valid 128-bit key is new byte[]{ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F }
or if you need to get it from base64 : Convert.FromBase64String("AAECAwQFBgcICQoLDA0ODw==")
.
The default blocksize is 128 bits, so the same byte-array will work as the IV.
Solution 2 - C#
Use the random number generator class (RNGCryptoServiceProvider) to fill a specified buffer with random bytes as follows:
var numberOfBits = 256; // or 192 or 128, however using a larger bit size renders the encrypted data harder to decipher
var ivBytes = new byte[numberOfBits / 8]; // 8 bits per byte
new RNGCryptoServiceProvider().GetBytes(ivBytes);
var rijndaelManagedCipher = new RijndaelManaged();
//Don't forget to set the explicitly set the block size for the IV if you're not using the default of 128
rijndaelManagedCipher.BlockSize = 256;
rijndaelManagedCipher.IV = ivBytes;
Note the same process could be used to derive a key. Hope this helps.
Solution 3 - C#
The RijndaelManaged algorithm supports key lengths of 128, 192, or 256 bits. Is your key one of these sizes?
Solution 4 - C#
here is the class i created
public class ByteCipher
{
// This constant is used to determine the keysize of the encryption algorithm in bits.
// We divide this by 8 within the code below to get the equivalent number of bytes.
private int _Keysize = (int)GlobalConfiguration.DataEncode_Key_Size;
private byte[] saltStringBytes;
private byte[] ivStringBytes;
// This constant determines the number of iterations for the password bytes generation function.
private const int DerivationIterations = 1000;
private string _passPhrase = GlobalConfiguration.DataEncode_Key;
private const string salt128 = "kljsdkkdlo4454GG";
private const string salt256 = "kljsdkkdlo4454GG00155sajuklmbkdl";
public ByteCipher(string passPhrase = null, DataCipherKeySize keySize = DataCipherKeySize.Key_128)
{
if (!string.IsNullOrEmpty(passPhrase?.Trim()))
_passPhrase = passPhrase;
_Keysize = keySize == DataCipherKeySize.Key_256 ? 256 : 128;
saltStringBytes = _Keysize == 256 ? Encoding.UTF8.GetBytes(salt256) : Encoding.UTF8.GetBytes(salt128);
ivStringBytes = _Keysize == 256 ? Encoding.UTF8.GetBytes("SSljsdkkdlo4454Maakikjhsd55GaRTP") : Encoding.UTF8.GetBytes("SSljsdkkdlo4454M");
}
public byte[] Encrypt(byte[] plainTextBytes)
{
if (plainTextBytes.Length <= 0)
return plainTextBytes;
using (var password = new Rfc2898DeriveBytes(_passPhrase, saltStringBytes, DerivationIterations))
{
var keyBytes = password.GetBytes(_Keysize / 8);
using (var symmetricKey = new RijndaelManaged())
{
symmetricKey.BlockSize = _Keysize;
symmetricKey.Mode = CipherMode.CBC;
symmetricKey.Padding = PaddingMode.PKCS7;
using (var encryptor = symmetricKey.CreateEncryptor(keyBytes, ivStringBytes))
{
using (var memoryStream = new MemoryStream())
{
using (var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
{
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
cryptoStream.FlushFinalBlock();
// Create the final bytes as a concatenation of the random salt bytes, the random iv bytes and the cipher bytes.
var cipherTextBytes = saltStringBytes;
cipherTextBytes = cipherTextBytes.Concat(ivStringBytes).ToArray();
cipherTextBytes = cipherTextBytes.Concat(memoryStream.ToArray()).ToArray();
memoryStream.Close();
cryptoStream.Close();
return cipherTextBytes;
}
}
}
}
}
}
public byte[] Decrypt(byte[] cipherTextBytesWithSaltAndIv)
{
if (cipherTextBytesWithSaltAndIv.Length <= 0)
return cipherTextBytesWithSaltAndIv;
var v = Encoding.UTF8.GetString(cipherTextBytesWithSaltAndIv.Take(_Keysize / 8).ToArray());
if (v != salt256 && v != salt128)
return cipherTextBytesWithSaltAndIv;
var cipherTextBytes = cipherTextBytesWithSaltAndIv.Skip((_Keysize / 8) * 2).Take(cipherTextBytesWithSaltAndIv.Length - ((_Keysize / 8) * 2)).ToArray();
using (var password = new Rfc2898DeriveBytes(_passPhrase, saltStringBytes, DerivationIterations))
{
var keyBytes = password.GetBytes(_Keysize / 8);
using (var symmetricKey = new RijndaelManaged())
{
symmetricKey.Mode = CipherMode.CBC;
symmetricKey.Padding = PaddingMode.PKCS7;
symmetricKey.BlockSize = _Keysize;
using (var decryptor = symmetricKey.CreateDecryptor(keyBytes, ivStringBytes))
{
using (var memoryStream = new MemoryStream(cipherTextBytes))
{
using (var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))
{
var plainTextBytes = new byte[cipherTextBytes.Length];
var decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
memoryStream.Close();
cryptoStream.Close();
return plainTextBytes;
}
}
}
}
}
}
}
Solution 5 - C#
I don't know the length of rijndaelCipher.Key if it is 24, then rijndaelCipher.Key = s.SubString(0, 24);
So easy.