os/security/cryptoplugins/cryptospiplugins/source/softwarecrypto/dsaverifyimpl.cpp
1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/os/security/cryptoplugins/cryptospiplugins/source/softwarecrypto/dsaverifyimpl.cpp Fri Jun 15 03:10:57 2012 +0200
1.3 @@ -0,0 +1,160 @@
1.4 +/*
1.5 +* Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).
1.6 +* All rights reserved.
1.7 +* This component and the accompanying materials are made available
1.8 +* under the terms of the License "Eclipse Public License v1.0"
1.9 +* which accompanies this distribution, and is available
1.10 +* at the URL "http://www.eclipse.org/legal/epl-v10.html".
1.11 +*
1.12 +* Initial Contributors:
1.13 +* Nokia Corporation - initial contribution.
1.14 +*
1.15 +* Contributors:
1.16 +*
1.17 +* Description:
1.18 +*
1.19 +*/
1.20 +
1.21 +
1.22 +#include "dsaverifyimpl.h"
1.23 +#include "pluginconfig.h"
1.24 +
1.25 +using namespace SoftwareCrypto;
1.26 +
1.27 +// Implementation of CDSAVerifierImpl
1.28 +CDSAVerifierImpl* CDSAVerifierImpl::NewL(const CKey& aKey)
1.29 + {
1.30 + CDSAVerifierImpl* self = CDSAVerifierImpl::NewLC(aKey);
1.31 + CleanupStack::Pop(self);
1.32 + return self;
1.33 + }
1.34 +
1.35 +CDSAVerifierImpl* CDSAVerifierImpl::NewLC(const CKey& aKey)
1.36 + {
1.37 + CDSAVerifierImpl* self = new(ELeave) CDSAVerifierImpl();
1.38 + CleanupStack::PushL(self);
1.39 + self->ConstructL(aKey);
1.40 + return self;
1.41 + }
1.42 +
1.43 +CDSAVerifierImpl::CDSAVerifierImpl()
1.44 + {
1.45 + }
1.46 +
1.47 +CDSAVerifierImpl::~CDSAVerifierImpl()
1.48 + {
1.49 + }
1.50 +
1.51 +void CDSAVerifierImpl::ConstructL(const CKey& aKey)
1.52 + {
1.53 + CVerifierImpl::ConstructL(aKey);
1.54 + }
1.55 +
1.56 +CExtendedCharacteristics* CDSAVerifierImpl::CreateExtendedCharacteristicsL()
1.57 + {
1.58 + // All Symbian software plug-ins have unlimited concurrency, cannot be reserved
1.59 + // for exclusive use and are not CERTIFIED to be standards compliant.
1.60 + return CExtendedCharacteristics::NewL(KMaxTInt, EFalse);
1.61 + }
1.62 +
1.63 +const CExtendedCharacteristics* CDSAVerifierImpl::GetExtendedCharacteristicsL()
1.64 + {
1.65 + return CDSAVerifierImpl::CreateExtendedCharacteristicsL();
1.66 + }
1.67 +
1.68 +TUid CDSAVerifierImpl::ImplementationUid() const
1.69 + {
1.70 + return KCryptoPluginDsaVerifierUid;
1.71 + }
1.72 +
1.73 +void CDSAVerifierImpl::SetKeyL(const CKey& aPublicKey)
1.74 + {
1.75 + DoSetKeyL(aPublicKey);
1.76 + Reset();
1.77 + }
1.78 +
1.79 +TInt CDSAVerifierImpl::GetMaximumInputLengthL() const
1.80 + {
1.81 + return KSha1HashLength;
1.82 + }
1.83 +
1.84 +void CDSAVerifierImpl::VerifyL(const TDesC8& aInput, const CCryptoParams& aSignature, TBool& aVerificationResult)
1.85 + {
1.86 + //Retrieve the parameter Q from the key
1.87 + const TInteger& tQ=iKey->GetBigIntL(KDsaKeyParameterQUid);
1.88 +
1.89 + //see HAC 11.56 or DSS section 6
1.90 + //I'll follow HAC as I like the description better
1.91 +
1.92 + // a) Obtain A's authenticate public key
1.93 +
1.94 + // b) Verify that 0 < r < q and 0 < s < q; if not reject signature
1.95 +
1.96 + //Retrieve the R&S in DSA signature from the array
1.97 +
1.98 + const TInteger& tR=aSignature.GetBigIntL(KDsaSignatureParameterRUid);
1.99 + const TInteger& tS=aSignature.GetBigIntL(KDsaSignatureParameterSUid);
1.100 +
1.101 + if (tR <= 0 || tR >= tQ)
1.102 + {
1.103 + aVerificationResult=EFalse;
1.104 + return;
1.105 + }
1.106 + if (tS <= 0 || tS >= tQ)
1.107 + {
1.108 + aVerificationResult=EFalse;
1.109 + return;
1.110 + }
1.111 +
1.112 +
1.113 + // c) Compute w = s^(-1) mod q and h(m)
1.114 + RInteger w = tS.InverseModL(tQ);
1.115 + CleanupStack::PushL(w);
1.116 + // Note that in order to be interoperable, compliant with the DSS, and
1.117 + // secure, aInput must be the result of a SHA-1 hash
1.118 + RInteger hm = RInteger::NewL(aInput);
1.119 + CleanupStack::PushL(hm);
1.120 +
1.121 + // d) Compute u1 = w * hm mod q and u2 = r * w mod q
1.122 + RInteger u1 = TInteger::ModularMultiplyL(w, hm, tQ);
1.123 + CleanupStack::PushL(u1);
1.124 +
1.125 + RInteger u2 = TInteger::ModularMultiplyL(tR, w, tQ);
1.126 + CleanupStack::PushL(u2);
1.127 +
1.128 + // e) Compute v = ((g^u1 * y^u2) mod p) mod q
1.129 +
1.130 + const TInteger& tG=iKey->GetBigIntL(KDsaKeyParameterGUid);
1.131 + const TInteger& tY=iKey->GetBigIntL(KDsaKeyParameterYUid);
1.132 + const TInteger& tP=iKey->GetBigIntL(KDsaKeyParameterPUid);
1.133 +
1.134 + RInteger temp = TInteger::ModularExponentiateL(tG, u1, tP);
1.135 + CleanupStack::PushL(temp);
1.136 + RInteger temp1 = TInteger::ModularExponentiateL(tY, u2, tP);
1.137 + CleanupStack::PushL(temp1);
1.138 + RInteger v = TInteger::ModularMultiplyL(temp, temp1, tP);
1.139 + CleanupStack::PushL(v);
1.140 + v %= tQ;
1.141 +
1.142 + // f) Accept the signature if v == r
1.143 + if(v == tR)
1.144 + {
1.145 + aVerificationResult = ETrue;
1.146 + }
1.147 +
1.148 + CleanupStack::PopAndDestroy(7, &w);
1.149 + }
1.150 +
1.151 +
1.152 +// Methods which are not supported can be excluded from the coverage.
1.153 +#ifdef _BullseyeCoverage
1.154 +#pragma suppress_warnings on
1.155 +#pragma BullseyeCoverage off
1.156 +#pragma suppress_warnings off
1.157 +#endif
1.158 +
1.159 +void CDSAVerifierImpl::InverseSignL(HBufC8*& /*aOutput*/, const CCryptoParams& /*aSignature*/)
1.160 + {
1.161 + // Override in subclass
1.162 + User::Leave(KErrNotSupported);
1.163 + }