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os/security/cryptoplugins/cryptospiplugins/source/softwarecrypto/rsafunction.cpp
author sl@SLION-WIN7.fritz.box
Fri, 15 Jun 2012 03:10:57 +0200
changeset 0 bde4ae8d615e
permissions -rw-r--r--
First public contribution. 
     1 /*

     2 * Copyright (c) 2003-2009 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of the License "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description: 

    15 *

    16 */

    17 

    18 

    19 #include <bigint.h>

    20 #include "keys.h"

    21 #include <asymmetrickeys.h>

    22 #include <cryptospi/cryptospidef.h>

    23 #include <cryptospi/cryptoparams.h>

    24 #include "rsafunction.h"

    25 #include "mont.h"

    26 

    27 using namespace CryptoSpi;

    28 

    29 // Public Encrypt

    30 void RSAFunction::EncryptL(const CKey& aPublicKey,

    31 	const TInteger& aInput, RInteger& aOutput)

    32 	{

    33 	const TInteger& N = aPublicKey.GetBigIntL(KRsaKeyParameterNUid);

    34 	const TInteger& E = aPublicKey.GetBigIntL(KRsaKeyParameterEUid);

    35 	FunctionL(N, E, aInput, aOutput);

    36 	}

    37 

    38 // Private Decrypt

    39 void RSAFunction::DecryptL(const CKey& aPrivateKey, const TInteger& aInput, RInteger& aOutput)

    40 	{

    41 	if (aPrivateKey.KeyProperty().iKeyType == KRsaPrivateKeyStandardUid)

    42 		{

    43 		const TInteger& N = aPrivateKey.GetBigIntL(KRsaKeyParameterNUid);

    44 		const TInteger& D = aPrivateKey.GetBigIntL(KRsaKeyParameterDUid);

    45 		FunctionL(N, D, aInput, aOutput);

    46 		}

    47 	else if (aPrivateKey.KeyProperty().iKeyType == KRsaPrivateKeyCRTUid)

    48 		{

    49 		FunctionCRTL(aPrivateKey, aInput, aOutput);

    50 		}

    51 	else

    52 		{

    53 		User::Leave(KErrNotSupported);

    54 		}

    55 	}

    56 

    57 // Private Encrypt

    58 void RSAFunction::SignL(const CKey& aPrivateKey, const TInteger& aInput, RInteger& aOutput)

    59 	{

    60 	if (aPrivateKey.KeyProperty().iKeyType == KRsaPrivateKeyStandardUid)

    61 		{

    62 		const TInteger& N = aPrivateKey.GetBigIntL(KRsaKeyParameterNUid);

    63 		const TInteger& D = aPrivateKey.GetBigIntL(KRsaKeyParameterDUid);

    64 		FunctionL(N, D, aInput, aOutput);

    65 		}

    66 	else if (aPrivateKey.KeyProperty().iKeyType == KRsaPrivateKeyCRTUid)

    67 		{

    68 		FunctionCRTL(aPrivateKey, aInput, aOutput);

    69 		}

    70 	else

    71 	{

    72 		User::Leave(KErrNotSupported);

    73 	}

    74 }

    75 

    76 // Public Decrypt

    77 void RSAFunction::VerifyL(const CKey& aPublicKey,

    78 	const TInteger& aInput, RInteger& aOutput)

    79 	{

    80 	const TInteger& N = aPublicKey.GetBigIntL(KRsaKeyParameterNUid);

    81 	const TInteger& E = aPublicKey.GetBigIntL(KRsaKeyParameterEUid);

    82 	FunctionL(N, E, aInput, aOutput);

    83 	}

    84 	

    85 // The RSA Trapdoor Function

    86 void RSAFunction::FunctionL(const TInteger& aModulus, const TInteger& aExponent, 

    87 							 const TInteger& aBase, RInteger& aOutput)

    88 	{

    89 	IsInputValidL(aBase, aModulus);

    90 

    91 	aOutput = TInteger::ModularExponentiateL(aBase, aExponent, aModulus);

    92 	}

    93 

    94 // The CRT version of the RSA Trapdoor Function

    95 void RSAFunction::FunctionCRTL(const CKey& aPrivateKey,

    96 								const TInteger& aInput, RInteger& aOutput)

    97 	{

    98 	const TInteger& N = aPrivateKey.GetBigIntL(KRsaKeyParameterNUid);

    99 	IsInputValidL(aInput, N);

   100 

   101 	const TInteger& P = aPrivateKey.GetBigIntL(KRsaKeyParameterPUid);

   102 	const TInteger& Q = aPrivateKey.GetBigIntL(KRsaKeyParameterQUid);

   103 	const TInteger& DP = aPrivateKey.GetBigIntL(KRsaKeyParameterDPUid);

   104 	const TInteger& DQ = aPrivateKey.GetBigIntL(KRsaKeyParameterDQUid);

   105 	const TInteger& QInv = aPrivateKey.GetBigIntL(KRsaKeyParameterQInvUid);

   106 

   107 	CMontgomeryStructure* montP = CMontgomeryStructure::NewLC(P);

   108 	CMontgomeryStructure* montQ = CMontgomeryStructure::NewLC(Q);

   109 	

   110 	// m1 = c^(dP) mod(p)

   111 	RInteger inputReduced = aInput.ModuloL(P);

   112 	CleanupStack::PushL(inputReduced);

   113 	const TInteger& m1 = montP->ExponentiateL(inputReduced, DP);

   114 	CleanupStack::PopAndDestroy(&inputReduced);

   115 

   116 	// m2 = c^(dQ) mod(Q)

   117 	inputReduced = aInput.ModuloL(Q);

   118 	CleanupStack::PushL(inputReduced);

   119 	const TInteger& m2 = montQ->ExponentiateL(inputReduced, DQ);

   120 	CleanupStack::PopAndDestroy(&inputReduced);

   121 	

   122 	// Calculate CRT

   123 	// h = (m1-m2) qInv mod(p)

   124 	RInteger h = m1.MinusL(m2);

   125 	CleanupStack::PushL(h);

   126 	h *= QInv;

   127 	h %= P;

   128 

   129 	// m = m2 + q * h

   130 	h *= Q;

   131 	h += m2;

   132 

   133 	aOutput = h;

   134 	CleanupStack::Pop(&h);

   135 

   136 	CleanupStack::PopAndDestroy(montQ);

   137 	CleanupStack::PopAndDestroy(montP);

   138 	}
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