static bool verify(Key key, Signature signature, byte[] data)
{
using (var dsa = useSigningService(key))
{
return dsa.verify(data, signature);
}
}
static Key removePrivateKey(Key key)
{
using (var dsa = useSigningService(key))
{
return dsa.exportKey(false);
}
}
static Signature sign(Key key, byte[] data)
{
using (var dsa = useSigningService(key))
{
var signed = dsa.sign(data);
return new Signature(new SignatureFormat(key.Format, DefaultHashAlgorithm), signed);
}
}
public EncryptionService(Key key)
{
_provider = new AesCryptoServiceProvider
{
KeySize = key.Format.BitSize.signed(),
Key = key.Data
};
_outputStream = new ReusableMemoryStream();
}
// Create an object of type IV from a given object of type Key.
// Usage of AesCryptoServiceProvider:
// - create it
// - set its key size according the the size of the input Key
// - use GenerateIV()
public static IV createRandomIV(Key key)
{
using (var aes = new AesCryptoServiceProvider())
{
aes.KeySize = key.Format.BitSize.signed();
// this should not be required?
// aes.Key = key.Data;
aes.GenerateIV();
return new IV(aes.IV);
}
}
public bool isSame(Key other)
{
return Format == other.Format && isSame(Data, other.Data);
}
static ISigningService useSigningService(Key key)
{
switch (key.Format.Algorithm)
{
case DSASigningService.AlgorithmName:
return new DSASigningService(key);
}
throw new InternalError("Unsupported key algorithm {0}".format(key.Format.Algorithm));
}
static bool hasPrivateKey(Key key)
{
var without = removePrivateKey(key);
return !without.isSame(key);
}
// Return decrypted data by using DecryptionService and the given Key
public static BufferReference decrypt(Key key, BufferReference content)
{
using (var service = new DecryptionService(key))
{
return service.decrypt(content);
}
}
// Return decrypted data by using DecryptionService and the given Key
public static BufferReference decrypt(Key key, byte[] content)
{
return decrypt(key, content.asBufferReference());
}
public static BufferReference encrypt(Key key, IV? iv_, BufferReference content)
{
using (var service = new EncryptionService(key))
{
var iv = iv_ ?? service.createRandomIV();
return service.encrypt(iv, content);
}
}
public static BufferReference encrypt(Key key, BufferReference content)
{
return encrypt(key, null, content);
}
public DSASigningService(Key key)
{
Debug.Assert(key.Format.Algorithm == AlgorithmName);
_provider = new DSACryptoServiceProvider(key.Format.BitSize.signed());
_provider.FromXmlString(System.Text.Encoding.UTF8.GetString(key.Data));
}
