/// <summary>
/// Decrypts encrypted private key file data.
/// </summary>
/// <param name="cipherInfo">The cipher info.</param>
/// <param name="cipherData">Encrypted data.</param>
/// <param name="passPhrase">Decryption pass phrase.</param>
/// <param name="binarySalt">Decryption binary salt.</param>
/// <param name="bytesOfSaltToPassword">The amount of bytes of the binary salt that are appended to the pass phrase before hashing it.</param>
/// <returns></returns>
/// <exception cref="ArgumentNullException"><paramref name="cipherInfo"/>, <paramref name="cipherData"/>, <paramref name="passPhrase"/> or <paramref name="binarySalt"/> is null.</exception>
private static byte[] DecryptKey(CipherInfo cipherInfo, byte[] cipherData, string passPhrase, byte[] binarySalt, int bytesOfSaltToPassword)
{
if (cipherInfo == null)
{
throw new ArgumentNullException("cipherInfo");
}
if (cipherData == null)
{
throw new ArgumentNullException("cipherData");
}
if (binarySalt == null)
{
throw new ArgumentNullException("binarySalt");
}
List <byte> cipherKey = new List <byte>();
var md5 = HashAlgorithmProvider.OpenAlgorithm(HashAlgorithmNames.Md5);
{
var passwordBytes = Encoding.UTF8.GetBytes(passPhrase);
var initVector = passwordBytes.Concat(binarySalt.Take(bytesOfSaltToPassword));
byte[] buffer;
CryptographicBuffer.CopyToByteArray(md5.HashData(CryptographicBuffer.CreateFromByteArray(initVector.ToArray())), out buffer);
var hash = buffer.AsEnumerable();
cipherKey.AddRange(hash);
while (cipherKey.Count < cipherInfo.KeySize / 8)
{
hash = hash.Concat(initVector);
CryptographicBuffer.CopyToByteArray(md5.HashData(CryptographicBuffer.CreateFromByteArray(hash.ToArray())), out buffer);
hash = buffer.AsEnumerable();
cipherKey.AddRange(hash);
}
}
var cipher = cipherInfo.Cipher(cipherKey.ToArray(), binarySalt);
return(cipher.Decrypt(cipherData));
}
/// <summary>
/// Decrypts encrypted private key file data.
/// </summary>
/// <param name="cipherInfo">The cipher info.</param>
/// <param name="cipherData">Encrypted data.</param>
/// <param name="passPhrase">Decryption pass phrase.</param>
/// <param name="binarySalt">Decryption binary salt.</param>
/// <returns>Decrypted byte array.</returns>
/// <exception cref="System.ArgumentNullException">cipherInfo</exception>
/// <exception cref="ArgumentNullException"><paramref name="cipherInfo" />, <paramref name="cipherData" />, <paramref name="passPhrase" /> or <paramref name="binarySalt" /> is null.</exception>
private static byte[] DecryptKey(CipherInfo cipherInfo, byte[] cipherData, string passPhrase, byte[] binarySalt)
{
if (cipherInfo == null)
{
throw new ArgumentNullException("cipherInfo");
}
if (cipherData == null)
{
throw new ArgumentNullException("cipherData");
}
if (binarySalt == null)
{
throw new ArgumentNullException("binarySalt");
}
List <byte> cipherKey = new List <byte>();
using (var md5 = new MD5Hash())
{
var passwordBytes = Encoding.UTF8.GetBytes(passPhrase);
// Use 8 bytes binary salkt
var initVector = passwordBytes.Concat(binarySalt.Take(8));
var hash = md5.ComputeHash(initVector.ToArray()).AsEnumerable();
cipherKey.AddRange(hash);
while (cipherKey.Count < cipherInfo.KeySize / 8)
{
hash = hash.Concat(initVector);
hash = md5.ComputeHash(hash.ToArray());
cipherKey.AddRange(hash);
}
}
var cipher = cipherInfo.Cipher(cipherKey.ToArray(), binarySalt);
return(cipher.Decrypt(cipherData));
}
