internal static Platform.HashAlgorithm GetHashAlgorithm(AsymmetricAlgorithm algorithm)
#endif
{
var hashAlgorithm = AsymmetricKeyAlgorithmProviderFactory.GetHashAlgorithmEnum(algorithm);
return(HashAlgorithmProvider.CreateHashAlgorithm(hashAlgorithm));
}
/// <inheritdoc />
protected internal override byte[] SignHash(byte[] data)
{
var hashAlgorithm = AsymmetricKeyAlgorithmProviderFactory.GetHashAlgorithmEnum(this.Algorithm);
var formatter = this.GetSignatureFormatter();
formatter.SetHashAlgorithm(hashAlgorithm.ToString());
return(formatter.CreateSignature(data));
}
/// <inheritdoc />
protected internal override bool VerifySignature(byte[] data, byte[] signature)
{
var hashAlgorithm = AsymmetricKeyAlgorithmProviderFactory.GetHashAlgorithmEnum(this.Algorithm);
using (var hash = this.GetHashAlgorithm())
{
var deformatter = this.GetSignatureDeformatter();
deformatter.SetHashAlgorithm(hashAlgorithm.ToString());
return(deformatter.VerifySignature(hash.ComputeHash(data), signature));
}
}
/// <inheritdoc />
protected internal override bool VerifyHash(byte[] data, byte[] signature)
{
try
{
var deformatter = this.GetSignatureDeformatter();
var hashAlgorithm = AsymmetricKeyAlgorithmProviderFactory.GetHashAlgorithmEnum(this.Algorithm);
deformatter.SetHashAlgorithm(hashAlgorithm.ToString());
return(deformatter.VerifySignature(data, signature));
}
catch (CryptographicException)
{
return(false);
}
}
/// <summary>
/// Gets the OID (or name) for a given hash algorithm.
/// </summary>
/// <param name="algorithm">The algorithm.</param>
/// <returns>A non-empty string.</returns>
internal static string GetHashAlgorithmOID(AsymmetricAlgorithm algorithm)
{
string algorithmName = HashAlgorithmProviderFactory.GetHashAlgorithmName(AsymmetricKeyAlgorithmProviderFactory.GetHashAlgorithmEnum(algorithm));
#if SILVERLIGHT
// Windows Phone 8.0 and Silverlight both are missing the
// CryptoConfig type. But that's ok since both platforms
// accept the algorithm name directly as well as the OID
// which we can't easily get to.
return(algorithmName);
#else
// Mono requires the OID, so we get it when we can.
return(Platform.CryptoConfig.MapNameToOID(algorithmName));
#endif
}
/// <summary>
/// Gets the string to pass to <see cref="Signature.GetInstance(string)"/>
/// for a given algorithm.
/// </summary>
/// <param name="algorithm">The algorithm.</param>
/// <returns>A non-empty string.</returns>
/// <exception cref="System.NotSupportedException">Thrown if the algorithm is not supported.</exception>
private static string GetSignatureName(AsymmetricAlgorithm algorithm)
{
string hashName = HashAlgorithmProviderFactory.GetHashAlgorithmName(AsymmetricKeyAlgorithmProviderFactory.GetHashAlgorithmEnum(algorithm));
switch (algorithm)
{
case AsymmetricAlgorithm.RsaSignPkcs1Sha1:
case AsymmetricAlgorithm.RsaSignPkcs1Sha256:
case AsymmetricAlgorithm.RsaSignPkcs1Sha384:
case AsymmetricAlgorithm.RsaSignPkcs1Sha512:
return(hashName + "withRSA");
case AsymmetricAlgorithm.RsaSignPssSha1:
case AsymmetricAlgorithm.RsaSignPssSha256:
case AsymmetricAlgorithm.RsaSignPssSha384:
case AsymmetricAlgorithm.RsaSignPssSha512:
default:
throw new NotSupportedException();
}
}
/// <summary>
/// Creates a hash algorithm instance that is appropriate for the given algorithm.T
/// </summary>
/// <returns>The hash algorithm.</returns>
private System.Security.Cryptography.HashAlgorithm GetHashAlgorithm()
{
var hashAlgorithm = AsymmetricKeyAlgorithmProviderFactory.GetHashAlgorithmEnum(this.Algorithm);
return(HashAlgorithmProvider.CreateHashAlgorithm(hashAlgorithm));
}