/// <summary>
/// Decrypts the given EncryptedValue object returning the source string.
/// </summary>
public string Decrypt(EncryptedValue encryptedValue, IIncomingLogicalMessageContext context)
{
string keyIdentifier;
if (TryGetKeyIdentifierHeader(out keyIdentifier, context))
{
return(DecryptUsingKeyIdentifier(encryptedValue, keyIdentifier));
}
Log.Warn($"Encrypted message has no '{EncryptionHeaders.RijndaelKeyIdentifier}' header. Possibility of data corruption. Upgrade endpoints that send message with encrypted properties.");
return(DecryptUsingAllKeys(encryptedValue));
}
static string Decrypt(EncryptedValue encryptedValue, byte[] key)
{
using (var rijndael = new RijndaelManaged())
{
var encrypted = Convert.FromBase64String(encryptedValue.EncryptedBase64Value);
rijndael.IV = Convert.FromBase64String(encryptedValue.Base64Iv);
rijndael.Mode = CipherMode.CBC;
rijndael.Key = key;
using (var decryptor = rijndael.CreateDecryptor())
using (var memoryStream = new MemoryStream(encrypted))
using (var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))
using (var reader = new StreamReader(cryptoStream))
{
return(reader.ReadToEnd());
}
}
}
string DecryptUsingKeyIdentifier(EncryptedValue encryptedValue, string keyIdentifier)
{
byte[] decryptionKey;
if (!keys.TryGetValue(keyIdentifier, out decryptionKey))
{
throw new InvalidOperationException($"Decryption key not available for key identifier '{keyIdentifier}'. Add this key to the rijndael encryption service configuration. Key identifiers are case sensitive.");
}
try
{
return(Decrypt(encryptedValue, decryptionKey));
}
catch (CryptographicException ex)
{
throw new InvalidOperationException("Unable to decrypt property using configured decryption key specified in key identifier header.", ex);
}
}
string DecryptUsingAllKeys(EncryptedValue encryptedValue)
{
var cryptographicExceptions = new List <CryptographicException>();
foreach (var key in decryptionKeys)
{
try
{
return(Decrypt(encryptedValue, key));
}
catch (CryptographicException exception)
{
cryptographicExceptions.Add(exception);
}
}
var message = $"Could not decrypt message. Tried {decryptionKeys.Count} keys.";
throw new AggregateException(message, cryptographicExceptions);
}