AaltoTLS.RecordLayer.RecordHandler.DecryptRecord C# (CSharp) Method

        private static bool DecryptRecord(CipherSuite cipherSuite, Record record, ICryptoTransform cipher)
        {
            BulkCipherAlgorithmType cipherType = cipherSuite.BulkCipherAlgorithm.Type;
            int recordIVLength = cipherSuite.BulkCipherAlgorithm.RecordIVLength;

            if (cipherType == BulkCipherAlgorithmType.AEAD) {
                int authTagSize = cipherSuite.BulkCipherAlgorithm.AuthenticationTagSize;

                // Remove explicit nonce from the beginning of the fragment
                byte[] tmp = new byte[record.Fragment.Length-recordIVLength];
                Buffer.BlockCopy(record.Fragment, recordIVLength, tmp, 0, tmp.Length);
                record.Fragment = tmp;

                // Make sure there is enough data for the authentication tag
                if (record.Fragment.Length < authTagSize) {
                    return false;
                }
            }

            // Replace the encrypted fragment with the decrypted fragment
            byte[] fragment = TransformRecordBytes(cipherType, cipher, record.Fragment);
            if (fragment == null) {
                return false;
            }
            record.Fragment = fragment;

            // Remove explicit IV from the beginning of the fragment if necessary
            if (cipherType == BulkCipherAlgorithmType.Block && record.Version.HasExplicitIV) {
                fragment = new byte[record.Fragment.Length-recordIVLength];
                Buffer.BlockCopy(record.Fragment, recordIVLength, fragment, 0, record.Fragment.Length-recordIVLength);
                record.Fragment = fragment;
            }

            return true;
        }