--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/crypto/weakcrypto/source/asymmetric/dsaverifier.cpp	Thu Jun 24 15:39:07 2010 +0530
@@ -0,0 +1,109 @@
+/*
+* Copyright (c) 2003-2009 Nokia Corporation and/or its subsidiary(-ies).
+* All rights reserved.
+* This component and the accompanying materials are made available
+* under the terms of the License "Eclipse Public License v1.0"
+* which accompanies this distribution, and is available
+* at the URL "http://www.eclipse.org/legal/epl-v10.html".
+*
+* Initial Contributors:
+* Nokia Corporation - initial contribution.
+*
+* Contributors:
+*
+* Description: 
+*
+*/
+
+
+#include <asymmetric.h>
+#include <asymmetrickeys.h>
+#include <bigint.h>
+
+EXPORT_C CDSAVerifier* CDSAVerifier::NewL(const CDSAPublicKey& aKey)
+	{
+	CDSAVerifier* self = new(ELeave)CDSAVerifier(aKey);
+	return self;
+	}
+
+EXPORT_C CDSAVerifier* CDSAVerifier::NewLC(const CDSAPublicKey& aKey)
+	{
+	CDSAVerifier* self = NewL(aKey);
+	CleanupStack::PushL(self);
+	return self;
+	}
+
+TInt CDSAVerifier::MaxInputLength(void) const
+	{
+	// return CSHA1::DIGESTBYTES
+	return 160;
+	}
+
+TBool CDSAVerifier::VerifyL(const TDesC8& aInput, 
+	const CDSASignature& aSignature) const
+	{
+	//see HAC 11.56 or DSS section 6
+	//I'll follow HAC as I like the description better
+
+	// a) Obtain A's authenticate public key
+
+	// b) Verify that 0 < r < q and 0 < s < q; if not reject signature
+	if (aSignature.R() <= 0 || aSignature.R() >= iPublicKey.Q())
+		{
+		return EFalse;
+		}
+	if (aSignature.S() <= 0 || aSignature.S() >= iPublicKey.Q())
+		{
+		return EFalse;
+		}
+
+	TBool result = EFalse;
+
+	// c) Compute w = s^(-1) mod q and h(m)
+	RInteger w = aSignature.S().InverseModL(iPublicKey.Q());
+	CleanupStack::PushL(w);
+	// Note that in order to be interoperable, compliant with the DSS, and
+	// secure, aInput must be the result of a SHA-1 hash
+	RInteger hm = RInteger::NewL(aInput);
+	CleanupStack::PushL(hm);
+
+	// d) Compute u1 = w * hm mod q and u2 = r * w mod q
+	RInteger u1 = TInteger::ModularMultiplyL(w, hm, iPublicKey.Q());
+	CleanupStack::PushL(u1);
+
+	RInteger u2 = TInteger::ModularMultiplyL(aSignature.R(), w, iPublicKey.Q());
+	CleanupStack::PushL(u2);
+
+	// e) Compute v = ((g^u1 * y^u2) mod p) mod q
+	RInteger temp = TInteger::ModularExponentiateL(iPublicKey.G(), u1,
+		iPublicKey.P());
+	CleanupStack::PushL(temp);
+	RInteger temp1 = TInteger::ModularExponentiateL(iPublicKey.Y(), u2,
+		iPublicKey.P());
+	CleanupStack::PushL(temp1);
+	RInteger v = TInteger::ModularMultiplyL(temp, temp1, iPublicKey.P());
+	CleanupStack::PushL(v);
+	v %= iPublicKey.Q();
+
+	// f) Accept the signature iff v == r
+	if(v == aSignature.R())
+		{
+		result = ETrue;
+		}
+
+	CleanupStack::PopAndDestroy(&v);
+	CleanupStack::PopAndDestroy(&temp1);
+	CleanupStack::PopAndDestroy(&temp);
+	CleanupStack::PopAndDestroy(&u2);
+	CleanupStack::PopAndDestroy(&u1);
+	CleanupStack::PopAndDestroy(&hm);
+	CleanupStack::PopAndDestroy(&w); 
+
+	return result;	
+	}
+
+CDSAVerifier::CDSAVerifier(const CDSAPublicKey& aKey)  
+	: iPublicKey(aKey)
+	{
+	}
+