void ComputeSignature(HashAlgorithm hash, AsymmetricSignatureFormatter formatter, string signatureMethod)
{
this.Signature.SignedInfo.ComputeReferenceDigests();
this.Signature.SignedInfo.ComputeHash(hash);
byte[] signature;
if (SecurityUtils.RequiresFipsCompliance && signatureMethod == SecurityAlgorithms.RsaSha256Signature)
{
// This is to avoid the RSAPKCS1SignatureFormatter.CreateSignature from using SHA256Managed (non-FIPS-Compliant).
// Hence we precompute the hash using SHA256CSP (FIPS compliant) and pass it to method.
// NOTE: RSAPKCS1SignatureFormatter does not understand SHA256CSP inherently and hence this workaround.
formatter.SetHashAlgorithm("SHA256");
signature = formatter.CreateSignature(hash.Hash);
}
else
{
signature = formatter.CreateSignature(hash);
}
this.Signature.SetSignatureValue(signature);
}
/// <summary>
/// Wrapper that creates a signature for SHA256 taking into consideration the special logic required for FIPS compliance
/// </summary>
/// <param name="formatter">the signature formatter</param>
/// <param name="hash">the hash algorithm</param>
/// <returns>byte array representing the signature</returns>
internal static byte[] CreateSignatureForSha256( AsymmetricSignatureFormatter formatter, HashAlgorithm hash )
{
if ( SecurityUtils.RequiresFipsCompliance )
{
//
// When FIPS is turned ON. We need to set the hash algorithm specifically
// as we need to pass the pre-computed buffer to CreateSignature, else
// for SHA256 and FIPS turned ON, the underlying formatter does not understand the
// OID for the hashing algorithm.
//
formatter.SetHashAlgorithm( "SHA256" );
return formatter.CreateSignature( hash.Hash );
}
else
{
//
// Calling the formatter with the object allows us to be Crypto-Agile
//
return formatter.CreateSignature( hash );
}
}
public FaultingAsymmetricSecurityKey(AsymmetricSecurityKey key = null, AsymmetricAlgorithm agorithm = null, AsymmetricSignatureDeformatter deformatter = null, AsymmetricSignatureFormatter formatter = null, HashAlgorithm hash = null, bool hasPrivateKey = false)
{
Key = key;
}
private void ComputeSignature(HashAlgorithm hash, AsymmetricSignatureFormatter formatter, string signatureMethod)
{
byte[] buffer;
this.Signature.SignedInfo.ComputeReferenceDigests();
this.Signature.SignedInfo.ComputeHash(hash);
if (System.IdentityModel.SecurityUtils.RequiresFipsCompliance && (signatureMethod == "http://www.w3.org/2001/04/xmldsig-more#rsa-sha256"))
{
formatter.SetHashAlgorithm("SHA256");
buffer = formatter.CreateSignature(hash.Hash);
}
else
{
buffer = formatter.CreateSignature(hash);
}
this.Signature.SetSignatureValue(buffer);
}
/// <summary>
/// Initializes a new instance of the <see cref="AsymmetricSignatureProvider"/> class used to create and verify signatures.
/// </summary>
/// <param name="key">
/// The <see cref="AsymmetricSecurityKey"/> that will be used for cryptographic operations.
/// </param>
/// <param name="algorithm">
/// The signature algorithm to apply.
/// </param>
/// <param name="willCreateSignatures">
/// If this <see cref="AsymmetricSignatureProvider"/> is required to create signatures then set this to true.
/// <para>
/// Creating signatures requires that the <see cref="AsymmetricSecurityKey"/> has access to a private key.
/// Verifying signatures (the default), does not require access to the private key.
/// </para>
/// </param>
/// <exception cref="ArgumentNullException">
/// 'key' is null.
/// </exception>
/// <exception cref="ArgumentNullException">
/// 'algorithm' is null.
/// </exception>
/// <exception cref="ArgumentException">
/// 'algorithm' contains only whitespace.
/// </exception>
/// <exception cref="ArgumentOutOfRangeException">
/// willCreateSignatures is true and <see cref="AsymmetricSecurityKey"/>.KeySize is less than <see cref="SignatureProviderFactory.MinimumAsymmetricKeySizeInBitsForSigning"/>.
/// </exception>
/// <exception cref="ArgumentOutOfRangeException">
/// <see cref="AsymmetricSecurityKey"/>.KeySize is less than <see cref="SignatureProviderFactory.MinimumAsymmetricKeySizeInBitsForVerifying"/>. Note: this is always checked.
/// </exception>
/// <exception cref="InvalidOperationException">
/// Is thrown if the <see cref="AsymmetricSecurityKey.GetHashAlgorithmForSignature"/> throws.
/// </exception>
/// <exception cref="InvalidOperationException">
/// Is thrown if the <see cref="AsymmetricSecurityKey.GetHashAlgorithmForSignature"/> returns null.
/// </exception>
/// <exception cref="InvalidOperationException">
/// Is thrown if the <see cref="AsymmetricSecurityKey.GetSignatureFormatter"/> throws.
/// </exception>
/// <exception cref="InvalidOperationException">
/// Is thrown if the <see cref="AsymmetricSecurityKey.GetSignatureFormatter"/> returns null.
/// </exception>
/// <exception cref="InvalidOperationException">
/// Is thrown if the <see cref="AsymmetricSecurityKey.GetSignatureDeformatter"/> throws.
/// </exception>
/// <exception cref="InvalidOperationException">
/// Is thrown if the <see cref="AsymmetricSecurityKey.GetSignatureDeformatter"/> returns null.
/// </exception>
/// <exception cref="InvalidOperationException">
/// Is thrown if the <see cref="AsymmetricSignatureFormatter.SetHashAlgorithm"/> throws.
/// </exception>
/// <exception cref="InvalidOperationException">
/// Is thrown if the <see cref="AsymmetricSignatureDeformatter.SetHashAlgorithm"/> throws.
/// </exception>
public AsymmetricSignatureProvider(AsymmetricSecurityKey key, string algorithm, bool willCreateSignatures = false)
{
if (key == null)
{
throw new ArgumentNullException("key");
}
if (algorithm == null)
{
throw new ArgumentNullException("algorithm");
}
if (string.IsNullOrWhiteSpace(algorithm))
{
throw new ArgumentException(string.Format(CultureInfo.InvariantCulture, ErrorMessages.IDX10002, "algorithm"));
}
if (willCreateSignatures)
{
if (key.KeySize < SignatureProviderFactory.MinimumAsymmetricKeySizeInBitsForSigning)
{
throw new ArgumentOutOfRangeException("key.KeySize", key.KeySize, string.Format(CultureInfo.InvariantCulture, ErrorMessages.IDX10631, key.GetType(), SignatureProviderFactory.MinimumAsymmetricKeySizeInBitsForSigning));
}
}
if (key.KeySize < SignatureProviderFactory.MinimumAsymmetricKeySizeInBitsForVerifying)
{
throw new ArgumentOutOfRangeException("key.KeySize", key.KeySize, string.Format(CultureInfo.InvariantCulture, ErrorMessages.IDX10630, key.GetType(), SignatureProviderFactory.MinimumAsymmetricKeySizeInBitsForVerifying));
}
this.key = key;
try
{
this.hash = this.key.GetHashAlgorithmForSignature(algorithm);
}
catch (Exception ex)
{
if (DiagnosticUtility.IsFatal(ex))
{
throw;
}
throw new InvalidOperationException(string.Format(CultureInfo.InvariantCulture, ErrorMessages.IDX10618, algorithm, this.key.ToString(), ex), ex);
}
if (this.hash == null)
{
throw new InvalidOperationException(string.Format(CultureInfo.InvariantCulture, ErrorMessages.IDX10611, algorithm, this.key.ToString()));
}
if (willCreateSignatures)
{
try
{
this.formatter = this.key.GetSignatureFormatter(algorithm);
this.formatter.SetHashAlgorithm(this.hash.GetType().ToString());
}
catch (Exception ex)
{
if (DiagnosticUtility.IsFatal(ex))
{
throw;
}
throw new InvalidOperationException(string.Format(CultureInfo.InvariantCulture, ErrorMessages.IDX10614, algorithm, this.key.ToString(), ex), ex);
}
if (this.formatter == null)
{
throw new InvalidOperationException(string.Format(CultureInfo.InvariantCulture, ErrorMessages.IDX10615, algorithm, this.key.ToString()));
}
}
try
{
this.deformatter = this.key.GetSignatureDeformatter(algorithm);
this.deformatter.SetHashAlgorithm(this.hash.GetType().ToString());
}
catch (Exception ex)
{
if (DiagnosticUtility.IsFatal(ex))
{
throw;
}
throw new InvalidOperationException(string.Format(CultureInfo.InvariantCulture, ErrorMessages.IDX10616, algorithm, this.key.ToString(), ex), ex);
}
if (this.deformatter == null)
{
throw new InvalidOperationException(string.Format(CultureInfo.InvariantCulture, ErrorMessages.IDX10617, algorithm, this.key.ToString()));
}
}
internal static void LogSigning(SignedXml signedXml, object key, SignatureDescription signatureDescription, HashAlgorithm hash, AsymmetricSignatureFormatter asymmetricSignatureFormatter)
{
if (InformationLoggingEnabled)
{
string data = string.Format(CultureInfo.InvariantCulture, SecurityResources.GetResourceString("Log_SigningAsymmetric"), new object[] { GetKeyName(key), signatureDescription.GetType().Name, hash.GetType().Name, asymmetricSignatureFormatter.GetType().Name });
WriteLine(signedXml, TraceEventType.Information, SignedXmlDebugEvent.Signing, data);
}
}
