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// ==++==
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// ==--==
// <OWNER>Microsoft</OWNER>
//
//
// DSASignatureDeformatter.cs
//
using System;
using System.Diagnostics.Contracts;
using System.Security.Cryptography.X509Certificates;
namespace System.Security.Cryptography {
[System.Runtime.InteropServices.ComVisible(true)]
public class DSASignatureDeformatter : AsymmetricSignatureDeformatter {
DSA _dsaKey; // DSA Key value to do decrypt operation
string _oid;
//
// public constructors
//
public DSASignatureDeformatter() {
// The hash algorithm is always SHA1
_oid = CryptoConfig.MapNameToOID("SHA1", OidGroup.HashAlgorithm);
}
public DSASignatureDeformatter(AsymmetricAlgorithm key) : this() {
if (key == null)
throw new ArgumentNullException("key");
Contract.EndContractBlock();
_dsaKey = (DSA) key;
}
//
// public methods
//
public override void SetKey(AsymmetricAlgorithm key) {
if (key == null)
throw new ArgumentNullException("key");
Contract.EndContractBlock();
_dsaKey = (DSA) key;
}
public override void SetHashAlgorithm(string strName) {
if (CryptoConfig.MapNameToOID(strName, OidGroup.HashAlgorithm) != _oid)
throw new CryptographicUnexpectedOperationException(Environment.GetResourceString("Cryptography_InvalidOperation"));
}
public override bool VerifySignature(byte[] rgbHash, byte[] rgbSignature) {
if (rgbHash == null)
throw new ArgumentNullException("rgbHash");
if (rgbSignature == null)
throw new ArgumentNullException("rgbSignature");
Contract.EndContractBlock();
if (_dsaKey == null)
throw new CryptographicUnexpectedOperationException(Environment.GetResourceString("Cryptography_MissingKey"));
return _dsaKey.VerifySignature(rgbHash, rgbSignature);
}
}
}
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