KeePassLib.Serialization.Kdb4File.AttachStreamEncryptor C# (CSharp) Метод

        private Stream AttachStreamEncryptor(Stream s)
        {
            MemoryStream ms = new MemoryStream();

            Debug.Assert(m_pbMasterSeed != null);
            Debug.Assert(m_pbMasterSeed.Length == 32);
            ms.Write(m_pbMasterSeed, 0, 32);

            Debug.Assert(m_pwDatabase != null);
            Debug.Assert(m_pwDatabase.MasterKey != null);
            ProtectedBinary pbinKey = m_pwDatabase.MasterKey.GenerateKey32(
                m_pbTransformSeed, m_pwDatabase.KeyEncryptionRounds);
            Debug.Assert(pbinKey != null);
            if(pbinKey == null)
                throw new SecurityException(KLRes.InvalidCompositeKey);
            byte[] pKey32 = pbinKey.ReadData();
            if((pKey32 == null) || (pKey32.Length != 32))
                throw new SecurityException(KLRes.InvalidCompositeKey);
            ms.Write(pKey32, 0, 32);

            SHA256Managed sha256 = new SHA256Managed();
            byte[] aesKey = sha256.ComputeHash(ms.ToArray());

            ms.Close();
            Array.Clear(pKey32, 0, 32);

            Debug.Assert(CipherPool.GlobalPool != null);
            ICipherEngine iEngine = CipherPool.GlobalPool.GetCipher(m_pwDatabase.DataCipherUuid);
            if(iEngine == null) throw new SecurityException(KLRes.FileUnknownCipher);
            return iEngine.EncryptStream(s, aesKey, m_pbEncryptionIV);
        }