152 lines
5.3 KiB
C++
152 lines
5.3 KiB
C++
// pkcspad.cpp - written and placed in the public domain by Wei Dai
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#include "pch.h"
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#include "pkcspad.h"
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#include <assert.h>
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NAMESPACE_BEGIN(CryptoPP)
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template<> const byte PKCS_DigestDecoration<SHA>::decoration[] = {0x30,0x21,0x30,0x09,0x06,0x05,0x2B,0x0E,0x03,0x02,0x1A,0x05,0x00,0x04,0x14};
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template<> const unsigned int PKCS_DigestDecoration<SHA>::length = sizeof(PKCS_DigestDecoration<SHA>::decoration);
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template<> const byte PKCS_DigestDecoration<MD2>::decoration[] = {0x30,0x20,0x30,0x0c,0x06,0x08,0x2a,0x86,0x48,0x86,0xf7,0x0d,0x02,0x02,0x05,0x00,0x04,0x10};
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template<> const unsigned int PKCS_DigestDecoration<MD2>::length = sizeof(PKCS_DigestDecoration<MD2>::decoration);
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template<> const byte PKCS_DigestDecoration<MD5>::decoration[] = {0x30,0x20,0x30,0x0c,0x06,0x08,0x2a,0x86,0x48,0x86,0xf7,0x0d,0x02,0x05,0x05,0x00,0x04,0x10};
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template<> const unsigned int PKCS_DigestDecoration<MD5>::length = sizeof(PKCS_DigestDecoration<MD5>::decoration);
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template<> const byte PKCS_DigestDecoration<RIPEMD160>::decoration[] = {0x30,0x21,0x30,0x09,0x06,0x05,0x2b,0x24,0x03,0x02,0x01,0x05,0x00,0x04,0x14};
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template<> const unsigned int PKCS_DigestDecoration<RIPEMD160>::length = sizeof(PKCS_DigestDecoration<RIPEMD160>::decoration);
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template<> const byte PKCS_DigestDecoration<SHA256>::decoration[] = {0x30,0x31,0x30,0x0d,0x06,0x09,0x60,0x86,0x48,0x01,0x65,0x03,0x04,0x02,0x01,0x05,0x00,0x04,0x20};
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template<> const unsigned int PKCS_DigestDecoration<SHA256>::length = sizeof(PKCS_DigestDecoration<SHA256>::decoration);
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template<> const byte PKCS_DigestDecoration<SHA384>::decoration[] = {0x30,0x41,0x30,0x0d,0x06,0x09,0x60,0x86,0x48,0x01,0x65,0x03,0x04,0x02,0x02,0x05,0x00,0x04,0x30};
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template<> const unsigned int PKCS_DigestDecoration<SHA384>::length = sizeof(PKCS_DigestDecoration<SHA384>::decoration);
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template<> const byte PKCS_DigestDecoration<SHA512>::decoration[] = {0x30,0x51,0x30,0x0d,0x06,0x09,0x60,0x86,0x48,0x01,0x65,0x03,0x04,0x02,0x03,0x05,0x00,0x04,0x40};
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template<> const unsigned int PKCS_DigestDecoration<SHA512>::length = sizeof(PKCS_DigestDecoration<SHA512>::decoration);
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unsigned int PKCS_EncryptionPaddingScheme::MaxUnpaddedLength(unsigned int paddedLength) const
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{
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return paddedLength/8 > 10 ? paddedLength/8-10 : 0;
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}
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void PKCS_EncryptionPaddingScheme::Pad(RandomNumberGenerator &rng, const byte *input, unsigned int inputLen, byte *pkcsBlock, unsigned int pkcsBlockLen) const
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{
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assert (inputLen <= MaxUnpaddedLength(pkcsBlockLen)); // this should be checked by caller
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// convert from bit length to byte length
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if (pkcsBlockLen % 8 != 0)
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{
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pkcsBlock[0] = 0;
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pkcsBlock++;
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}
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pkcsBlockLen /= 8;
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pkcsBlock[0] = 2; // block type 2
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// pad with non-zero random bytes
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for (unsigned i = 1; i < pkcsBlockLen-inputLen-1; i++)
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pkcsBlock[i] = (byte)rng.GenerateWord32(1, 0xff);
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pkcsBlock[pkcsBlockLen-inputLen-1] = 0; // separator
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memcpy(pkcsBlock+pkcsBlockLen-inputLen, input, inputLen);
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}
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DecodingResult PKCS_EncryptionPaddingScheme::Unpad(const byte *pkcsBlock, unsigned int pkcsBlockLen, byte *output) const
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{
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bool invalid = false;
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unsigned int maxOutputLen = MaxUnpaddedLength(pkcsBlockLen);
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// convert from bit length to byte length
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if (pkcsBlockLen % 8 != 0)
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{
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invalid = (pkcsBlock[0] != 0) || invalid;
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pkcsBlock++;
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}
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pkcsBlockLen /= 8;
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// Require block type 2.
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invalid = (pkcsBlock[0] != 2) || invalid;
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// skip past the padding until we find the seperator
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unsigned i=1;
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while (i<pkcsBlockLen && pkcsBlock[i++]) { // null body
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}
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assert(i==pkcsBlockLen || pkcsBlock[i-1]==0);
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unsigned int outputLen = pkcsBlockLen - i;
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invalid = (outputLen > maxOutputLen) || invalid;
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if (invalid)
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return DecodingResult();
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memcpy (output, pkcsBlock+i, outputLen);
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return DecodingResult(outputLen);
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}
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// ********************************************************
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unsigned int PKCS_SignaturePaddingScheme::MaxUnpaddedLength(unsigned int paddedLength) const
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{
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return paddedLength/8 > 10 ? paddedLength/8-10 : 0;
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}
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void PKCS_SignaturePaddingScheme::Pad(RandomNumberGenerator &, const byte *input, unsigned int inputLen, byte *pkcsBlock, unsigned int pkcsBlockLen) const
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{
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assert (inputLen <= MaxUnpaddedLength(pkcsBlockLen)); // this should be checked by caller
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// convert from bit length to byte length
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if (pkcsBlockLen % 8 != 0)
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{
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pkcsBlock[0] = 0;
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pkcsBlock++;
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}
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pkcsBlockLen /= 8;
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pkcsBlock[0] = 1; // block type 1
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// padd with 0xff
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memset(pkcsBlock+1, 0xff, pkcsBlockLen-inputLen-2);
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pkcsBlock[pkcsBlockLen-inputLen-1] = 0; // separator
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memcpy(pkcsBlock+pkcsBlockLen-inputLen, input, inputLen);
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}
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DecodingResult PKCS_SignaturePaddingScheme::Unpad(const byte *pkcsBlock, unsigned int pkcsBlockLen, byte *output) const
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{
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unsigned int maxOutputLen = MaxUnpaddedLength(pkcsBlockLen);
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// convert from bit length to byte length
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if (pkcsBlockLen % 8 != 0)
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{
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if (pkcsBlock[0] != 0)
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return DecodingResult();
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pkcsBlock++;
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}
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pkcsBlockLen /= 8;
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// Require block type 1.
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if (pkcsBlock[0] != 1)
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return DecodingResult();
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// skip past the padding until we find the seperator
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unsigned i=1;
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while (i<pkcsBlockLen && pkcsBlock[i++])
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if (pkcsBlock[i-1] != 0xff) // not valid padding
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return DecodingResult();
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assert(i==pkcsBlockLen || pkcsBlock[i-1]==0);
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unsigned int outputLen = pkcsBlockLen - i;
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if (outputLen > maxOutputLen)
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return DecodingResult();
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memcpy (output, pkcsBlock+i, outputLen);
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return DecodingResult(outputLen);
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}
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NAMESPACE_END
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