/// <summary>Return the decrypted session data for the packet.</summary>
private static byte[] GetSessionData(SymmetricKeyEncSessionPacket keyData, ReadOnlySpan <byte> rawPassword)
{
byte[] key = Array.Empty <byte>();
try
{
key = new byte[PgpUtilities.GetKeySize(keyData.EncAlgorithm) / 8];
S2kBasedEncryption.MakeKey(rawPassword, keyData.S2k.HashAlgorithm, keyData.S2k.GetIV(), keyData.S2k.IterationCount, key);
if (keyData.SecKeyData?.Length > 0)
{
using var keyCipher = PgpUtilities.GetSymmetricAlgorithm(keyData.EncAlgorithm);
using var keyDecryptor = new ZeroPaddedCryptoTransform(keyCipher.CreateDecryptor(key, new byte[(keyCipher.BlockSize + 7) / 8]));
return(keyDecryptor.TransformFinalBlock(keyData.SecKeyData, 0, keyData.SecKeyData.Length));
}
else
{
var sessionData = new byte[key.Length + 1];
sessionData[0] = (byte)keyData.EncAlgorithm;
key.CopyTo(sessionData, 1);
return(sessionData);
}
}
finally
{
CryptographicOperations.ZeroMemory(key);
}
}
/// <summary>Add a PBE encryption method to the encrypted object.</summary>
public void AddMethod(ReadOnlySpan <byte> rawPassPhrase, PgpHashAlgorithm s2kDigest)
{
S2k s2k = PgpUtilities.GenerateS2k(s2kDigest, 0x60);
byte[] key = new byte[PgpUtilities.GetKeySize(defAlgorithm) / 8];
S2kBasedEncryption.MakeKey(rawPassPhrase, s2kDigest, s2k.GetIV(), s2k.IterationCount, key);
methods.Add(new PbeMethod(defAlgorithm, s2k, key));
}