Exemple #1
0
        public DecryptedData DecryptData(EncryptedPacket encryptedPacket, int keyLength, RSAEncryption rsaParams, DigitalSignature digitalSignature, string pathToRecipientPrivateKey, string pathToSenderPublicKey)
        {
            var decryptedSessionKey = rsaParams.DecryptData(encryptedPacket.EncryptedSessionKey, keyLength, pathToRecipientPrivateKey);

            using (var hmac = new HMACSHA256(decryptedSessionKey))
            {
                var hmacToCheck = hmac.ComputeHash(encryptedPacket.EncryptedData);

                if (!Compare(encryptedPacket.Hmac, hmacToCheck))
                {
                    throw new CryptographicException("HMAC for decryption does not match encrypted packet.");
                }

                if (!digitalSignature.VerifySignature(encryptedPacket.Hmac, encryptedPacket.Signature, keyLength, pathToSenderPublicKey))
                {
                    throw new CryptographicException("Digital Signature can not be verified.");
                }
            }

            var decryptedData = _aes.Decrypt(encryptedPacket.EncryptedData, decryptedSessionKey, encryptedPacket.Iv);

            // Need to account for encryptedPacket.Filename being null here - in case a user is decrypting a packet created with v1.0.0
            var originalFilename = encryptedPacket.Filename != null?_aes.Decrypt(encryptedPacket.Filename, decryptedSessionKey, encryptedPacket.Iv)
                                       : defaultFilename;

            return(new DecryptedData {
                FileContents = decryptedData, Filename = Encoding.ASCII.GetString(originalFilename), Version1Packet = encryptedPacket.Filename == null
            });
        }
        private static DecryptedData Decrypt(EncryptedPacket encryptedPacket, int keyLength, string sendersPublicKeyPath, string recipientsPrivateKeyPath)
        {
            var encryptor     = new RSAEncryption();
            var digitalSigner = new DigitalSignature();

            var hybrid = new HybridEncryption();

            var decryptedData = hybrid.DecryptData(encryptedPacket, keyLength, encryptor, digitalSigner, recipientsPrivateKeyPath, sendersPublicKeyPath);

            return(decryptedData);
        }
Exemple #3
0
        public EncryptedPacket EncryptData(byte[] original, int keyLength, RSAEncryption rsaParams, DigitalSignature digitalSignature, string pathToRecipientPublicKey, string pathToSenderPrivateKey, string filename)
        {
            var sessionKey = _aes.GenerateRandomNumber(32);

            var encryptedPacket = new EncryptedPacket {
                Iv = _aes.GenerateRandomNumber(16)
            };

            encryptedPacket.EncryptedData = _aes.Encrypt(original, sessionKey, encryptedPacket.Iv);

            encryptedPacket.Filename = _aes.Encrypt(Encoding.ASCII.GetBytes(filename), sessionKey, encryptedPacket.Iv);

            encryptedPacket.EncryptedSessionKey = rsaParams.EncryptData(sessionKey, keyLength, pathToRecipientPublicKey);

            using (var hmac = new HMACSHA256(sessionKey))
            {
                encryptedPacket.Hmac = hmac.ComputeHash(encryptedPacket.EncryptedData);
            }

            encryptedPacket.Signature = digitalSignature.SignData(encryptedPacket.Hmac, keyLength, pathToSenderPrivateKey);

            return(encryptedPacket);
        }