/*
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* The RSA PK cryptosystem
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*
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* Copyright (C) 2006 Christophe Devine
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License, version 2.1 as published by the Free Software Foundation.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301 USA
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*/
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/*
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* RSA was designed by Ron Rivest, Adi Shamir and Len Adleman.
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*
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* http://theory.lcs.mit.edu/~rivest/rsapaper.pdf
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* http://www.cacr.math.uwaterloo.ca/hac/about/chap8.pdf
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*/
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#ifndef _CRT_SECURE_NO_DEPRECATE
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#define _CRT_SECURE_NO_DEPRECATE 1
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#endif
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#include <common.h>
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#include <rsa.h>
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#if !defined(NO_GENPRIME)
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/*
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* Generate an RSA keypair
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*/
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int rsa_gen_key( rsa_context *ctx, int nbits, int exponent,
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int (*rng_f)(void *), void *rng_d )
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{
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int ret;
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mpi P1, Q1, H, G;
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if( nbits < 128 || exponent < 3 || rng_f == NULL )
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return( ERR_RSA_BAD_INPUT_DATA );
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mpi_init( &P1, &Q1, &H, &G, NULL );
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memset( ctx, 0, sizeof( rsa_context ) );
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/*
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* find primes P and Q with Q < P so that:
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* GCD( E, (P-1)*(Q-1) ) == 1
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*/
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CHK( mpi_lset( &ctx->E, exponent ) );
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nbits >>= 1;
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do
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{
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CHK( mpi_gen_prime( &ctx->P, nbits, 0, rng_f, rng_d ) );
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CHK( mpi_gen_prime( &ctx->Q, nbits, 0, rng_f, rng_d ) );
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if( mpi_cmp_mpi( &ctx->P, &ctx->Q ) < 0 )
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mpi_swap( &ctx->P, &ctx->Q );
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if( mpi_cmp_mpi( &ctx->P, &ctx->Q ) == 0 )
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continue;
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CHK( mpi_mul_mpi( &ctx->N, &ctx->P, &ctx->Q ) );
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CHK( mpi_sub_int( &P1, &ctx->P, 1 ) );
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CHK( mpi_sub_int( &Q1, &ctx->Q, 1 ) );
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CHK( mpi_mul_mpi( &H, &P1, &Q1 ) );
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CHK( mpi_gcd( &G, &ctx->E, &H ) );
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}
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while( mpi_cmp_int( &G, 1 ) != 0 );
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/*
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* D = E^-1 mod ((P-1)*(Q-1))
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* DP = D mod (P - 1)
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* DQ = D mod (Q - 1)
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* QP = Q^-1 mod P
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*/
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CHK( mpi_inv_mod( &ctx->D , &ctx->E, &H ) );
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CHK( mpi_mod_mpi( &ctx->DP, &ctx->D, &P1 ) );
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CHK( mpi_mod_mpi( &ctx->DQ, &ctx->D, &Q1 ) );
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CHK( mpi_inv_mod( &ctx->QP, &ctx->Q, &ctx->P ) );
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ctx->len = ( mpi_size( &ctx->N ) + 7 ) >> 3;
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cleanup:
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mpi_free( &P1, &Q1, &H, &G, NULL );
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if( ret != 0 )
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{
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rsa_free( ctx );
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return( ERR_RSA_KEY_GEN_FAILED | ret );
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}
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return( 0 );
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}
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#endif
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/*
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* Perform an RSA public key operation
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*/
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int rsa_public( rsa_context *ctx,
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unsigned char *input, int ilen,
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unsigned char *output, int *olen )
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{
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int ret;
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mpi T;
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// if( ilen != ctx->len || olen != ctx->len )
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// return( ERR_RSA_BAD_INPUT_DATA );
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mpi_init( &T, NULL );
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CHK( mpi_import( &T, input, ilen ) );
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if( mpi_cmp_mpi( &T, &ctx->N ) >= 0 )
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{
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mpi_free( &T, NULL );
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return( ERR_RSA_BAD_INPUT_DATA );
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}
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CHK( mpi_exp_mod( &T, &T, &ctx->E, &ctx->N, &ctx->RN ) );
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CHK( mpi_export( &T, output, olen ) );
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cleanup:
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mpi_free( &T, NULL );
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if( ret != 0 )
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return( ERR_RSA_PUBLIC_FAILED | ret );
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return( 0 );
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}
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/*
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* Perform an RSA private key operation
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*/
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int rsa_private( rsa_context *ctx,
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unsigned char *input, int ilen,
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unsigned char *output, int *olen )
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{
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int ret;
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mpi T, T1, T2;
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//if( ilen != ctx->len || olen != ctx->len )
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// return( ERR_RSA_BAD_INPUT_DATA );
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mpi_init( &T, &T1, &T2, NULL );
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CHK( mpi_import( &T, input, ilen ) );
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if( mpi_cmp_mpi( &T, &ctx->N ) >= 0 )
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{
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mpi_free( &T, NULL );
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return( ERR_RSA_BAD_INPUT_DATA );
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}
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#if 0
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CHK( mpi_exp_mod( &T, &T, &ctx->D, &ctx->N, &ctx->RN ) );
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#else
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/*
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* faster decryption using the CRT
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*
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* T1 = input ^ dP mod P
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* T2 = input ^ dQ mod Q
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*/
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CHK( mpi_exp_mod( &T1, &T, &ctx->DP, &ctx->P, &ctx->RP ) );
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CHK( mpi_exp_mod( &T2, &T, &ctx->DQ, &ctx->Q, &ctx->RQ ) );
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/*
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* T = (T1 - T2) * (Q^-1 mod P) mod P
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*/
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CHK( mpi_sub_mpi( &T, &T1, &T2 ) );
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CHK( mpi_mul_mpi( &T1, &T, &ctx->QP ) );
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CHK( mpi_mod_mpi( &T, &T1, &ctx->P ) );
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/*
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* output = T2 + T * Q
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*/
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CHK( mpi_mul_mpi( &T1, &T, &ctx->Q ) );
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CHK( mpi_add_mpi( &T, &T2, &T1 ) );
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#endif
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CHK( mpi_export( &T, output, olen ) );
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cleanup:
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mpi_free( &T, &T1, &T2, NULL );
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if( ret != 0 )
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return( ERR_RSA_PRIVATE_FAILED | ret );
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return( 0 );
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}
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/*
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* Check if the public key is valid
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*/
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int rsa_check_pubkey( rsa_context *ctx )
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{
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if( ( ctx->N.p[0] & 1 ) == 0 ||
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( ctx->E.p[0] & 1 ) == 0 )
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return( ERR_RSA_KEY_CHK_FAILED );
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if( mpi_size( &ctx->N ) < 128 ||
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mpi_size( &ctx->N ) > 4096 )
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return( ERR_RSA_KEY_CHK_FAILED );
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if( mpi_size( &ctx->E ) < 2 ||
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mpi_size( &ctx->E ) > 64 )
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return( ERR_RSA_KEY_CHK_FAILED );
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return( 0 );
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}
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/*
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* Check if the private key is valid
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*/
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int rsa_check_privkey( rsa_context *ctx )
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{
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int ret = 0;
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mpi TN, P1, Q1, H, G;
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mpi_init( &TN, &P1, &Q1, &H, &G, NULL );
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CHK( mpi_mul_mpi( &TN, &ctx->P, &ctx->Q ) );
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CHK( mpi_sub_int( &P1, &ctx->P, 1 ) );
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CHK( mpi_sub_int( &Q1, &ctx->Q, 1 ) );
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CHK( mpi_mul_mpi( &H, &P1, &Q1 ) );
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CHK( mpi_gcd( &G, &ctx->E, &H ) );
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if( mpi_cmp_mpi( &TN, &ctx->N ) == 0 &&
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mpi_cmp_int( &G, 1 ) == 0 )
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{
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mpi_free( &TN, &P1, &Q1, &H, &G, NULL );
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return( 0 );
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}
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cleanup:
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mpi_free( &TN, &P1, &Q1, &H, &G, NULL );
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return( ERR_RSA_KEY_CHK_FAILED | ret );
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}
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/*
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* Add the PKCS#1 v1.5 padding and do a public RSA
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*/
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int rsa_pkcs1_encrypt( rsa_context *ctx,
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unsigned char *input, int ilen,
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unsigned char *output, int *olen )
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{
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int nb_pad;
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unsigned char *p = output;
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if( *olen != ctx->len || *olen < ilen + 11 )
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{
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return( ERR_RSA_BAD_INPUT_DATA );
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}
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nb_pad = *olen - 3 - ilen;
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*p++ = 0;
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*p++ = RSA_CRYPT;
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while( nb_pad-- > 0 )
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{
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do { *p = rand(); } while( *p == 0 );
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p++;
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}
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*p++ = 0;
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memcpy( p, input, ilen );
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return( rsa_public( ctx, output, *olen, output, olen ) );
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}
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/*
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* Do a private RSA, removes the PKCS#1 v1.5 padding
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*/
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int rsa_pkcs1_decrypt( rsa_context *ctx,
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unsigned char *input, int ilen,
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unsigned char *output, int *olen )
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{
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int ret;
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unsigned char *p, buf[512];
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if( ilen != ctx->len || ilen < 16 || ilen > 512 )
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return( ERR_RSA_BAD_INPUT_DATA );
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if( ( ret = rsa_private( ctx, input, ilen, buf, &ilen ) ) != 0 )
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return( ret );
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p = buf;
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if( *p++ != 0 || *p++ != RSA_CRYPT )
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return( ERR_RSA_INVALID_PADDING );
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while( *p != 0 )
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{
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if( p >= buf + ilen - 1 )
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return( ERR_RSA_INVALID_PADDING );
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p++;
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}
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p++;
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if( *olen < ilen - (int)(p - buf) )
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return( ERR_RSA_INVALID_PADDING );
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*olen = ilen - (int)(p - buf);
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memcpy( output, p, *olen );
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return( 0 );
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}
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/*
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* Perform a private RSA to sign a message digest
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*/
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int rsa_pkcs1_sign( rsa_context *ctx, int alg_id,
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unsigned char *hash, int hashlen,
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unsigned char *sig, int siglen )
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{
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int nb_pad;
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unsigned char *p = sig;
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if( siglen != ctx->len || siglen < 16 )
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return( ERR_RSA_BAD_INPUT_DATA );
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switch( alg_id )
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{
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case RSA_RAW:
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nb_pad = siglen - 3 - hashlen;
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break;
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case RSA_MD2:
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case RSA_MD4:
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case RSA_MD5:
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nb_pad = siglen - 3 - 34;
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break;
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case RSA_SHA1:
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nb_pad = siglen - 3 - 35;
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break;
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default:
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return( ERR_RSA_BAD_INPUT_DATA );
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}
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if( nb_pad < 8 )
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return( ERR_RSA_BAD_INPUT_DATA );
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*p++ = 0;
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*p++ = RSA_SIGN;
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memset( p, 0xFF, nb_pad );
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p += nb_pad;
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*p++ = 0;
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switch( alg_id )
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{
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case RSA_RAW:
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memcpy( p, hash, hashlen );
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break;
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case RSA_MD2:
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memcpy( p, ASN1_HASH_MDX, 18 );
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memcpy( p + 18, hash, 16 );
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p[13] = 2; break;
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case RSA_MD4:
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memcpy( p, ASN1_HASH_MDX, 18 );
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memcpy( p + 18, hash, 16 );
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p[13] = 4; break;
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case RSA_MD5:
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memcpy( p, ASN1_HASH_MDX, 18 );
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memcpy( p + 18, hash, 16 );
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p[13] = 5; break;
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case RSA_SHA1:
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memcpy( p, ASN1_HASH_SHA1, 15 );
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memcpy( p + 15, hash, 20 );
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break;
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default:
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return( ERR_RSA_BAD_INPUT_DATA );
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}
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return( rsa_private( ctx, sig, siglen, sig, &siglen ) );
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}
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/*
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* Perform a public RSA and check the message digest
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*/
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int rsa_pkcs1_verify( rsa_context *ctx, int alg_id,
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unsigned char *hash, int hashlen,
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unsigned char *sig, int siglen )
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{
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int ret, len;
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unsigned char *p, c, buf[512];
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if( siglen != ctx->len || siglen < 16 || siglen > 512 )
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return( ERR_RSA_BAD_INPUT_DATA );
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if( ( ret = rsa_public( ctx, sig, siglen, buf, &siglen ) ) != 0 )
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return( ret );
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p = buf;
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if( *p++ != 0 || *p++ != RSA_SIGN )
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return( ERR_RSA_INVALID_PADDING );
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while( *p != 0 )
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{
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if( p >= buf + siglen - 1 || *p != 0xFF )
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return( ERR_RSA_INVALID_PADDING );
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p++;
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}
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p++;
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len = siglen - (int)( p - buf );
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if( len == 34 )
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{
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c = p[13];
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p[13] = 0;
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if( memcmp( p, ASN1_HASH_MDX, 18 ) != 0 )
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return( ERR_RSA_VERIFY_FAILED );
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if( ( c == 2 && alg_id == RSA_MD2 ) ||
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( c == 4 && alg_id == RSA_MD4 ) ||
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( c == 5 && alg_id == RSA_MD5 ) )
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{
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if( memcmp( p + 18, hash, 16 ) == 0 )
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return( 0 );
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else
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return( ERR_RSA_VERIFY_FAILED );
|
}
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}
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if( len == 35 && alg_id == RSA_SHA1 )
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{
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if( memcmp( p, ASN1_HASH_SHA1, 15 ) == 0 &&
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memcmp( p + 15, hash, 20 ) == 0 )
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return( 0 );
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else
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return( ERR_RSA_VERIFY_FAILED );
|
}
|
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if( len == hashlen && alg_id == RSA_RAW )
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{
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if( memcmp( p, hash, hashlen ) == 0 )
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return( 0 );
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else
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return( ERR_RSA_VERIFY_FAILED );
|
}
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return( ERR_RSA_INVALID_PADDING );
|
}
|
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/*
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* Free the components of an RSA key
|
*/
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void rsa_free( rsa_context *ctx )
|
{
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mpi_free( &ctx->N, &ctx->E, &ctx->D,
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&ctx->P, &ctx->Q, &ctx->DP,
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&ctx->DQ, &ctx->QP, &ctx->RN,
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&ctx->RP, &ctx->RQ, NULL );
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}
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//#include "md5.h"
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#define PTLEN 24
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#define CTLEN 128
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/*
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* Checkup routine
|
*/
|
int main ( void )
|
{
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int len;
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rsa_context rsa;
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unsigned char md5sum[16];
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unsigned char rsa_plaintext[PTLEN];
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unsigned char rsa_decrypted[PTLEN];
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unsigned char rsa_ciphertext[CTLEN];
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memset( &rsa, 0, sizeof( rsa ) );
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rsa.len = 128;
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mpi_read( &rsa.N , "9292758453063D803DD603D5E777D788" \
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"8ED1D5BF35786190FA2F23EBC0848AEA" \
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"DDA92CA6C3D80B32C4D109BE0F36D6AE" \
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"7130B9CED7ACDF54CFC7555AC14EEBAB" \
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"93A89813FBF3C4F8066D2D800F7C38A8" \
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"1AE31942917403FF4946B0A83D3D3E05" \
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"EE57C6F5F5606FB5D4BC6CD34EE0801A" \
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"5E94BB77B07507233A0BC7BAC8F90F79", 16 );
|
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mpi_read( &rsa.E , "10001", 16 );
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mpi_read( &rsa.D , "24BF6185468786FDD303083D25E64EFC" \
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"66CA472BC44D253102F8B4A9D3BFA750" \
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"91386C0077937FE33FA3252D28855837" \
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"AE1B484A8A9A45F7EE8C0C634F99E8CD" \
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"DF79C5CE07EE72C7F123142198164234" \
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"CABB724CF78B8173B9F880FC86322407" \
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"AF1FEDFDDE2BEB674CA15F3E81A1521E" \
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"071513A1E85B5DFA031F21ECAE91A34D", 16 );
|
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mpi_read( &rsa.P , "C36D0EB7FCD285223CFB5AABA5BDA3D8" \
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"2C01CAD19EA484A87EA4377637E75500" \
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"FCB2005C5C7DD6EC4AC023CDA285D796" \
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"C3D9E75E1EFC42488BB4F1D13AC30A57", 16 );
|
mpi_read( &rsa.Q , "C000DF51A7C77AE8D7C7370C1FF55B69" \
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"E211C2B9E5DB1ED0BF61D0D9899620F4" \
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"910E4168387E3C30AA1E00C339A79508" \
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"8452DD96A9A5EA5D9DCA68DA636032AF", 16 );
|
|
mpi_read( &rsa.DP, "C1ACF567564274FB07A0BBAD5D26E298" \
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"3C94D22288ACD763FD8E5600ED4A702D" \
|
"F84198A5F06C2E72236AE490C93F07F8" \
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"3CC559CD27BC2D1CA488811730BB5725", 16 );
|
mpi_read( &rsa.DQ, "4959CBF6F8FEF750AEE6977C155579C7" \
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"D8AAEA56749EA28623272E4F7D0592AF" \
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"7C1F1313CAC9471B5C523BFE592F517B" \
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"407A1BD76C164B93DA2D32A383E58357", 16 );
|
mpi_read( &rsa.QP, "9AE7FBC99546432DF71896FC239EADAE" \
|
"F38D18D2B2F0E2DD275AA977E2BF4411" \
|
"F5A3B2A5D33605AEBBCCBA7FEB9F2D2F" \
|
"A74206CEC169D74BF5A8C50D6F48EA08", 16 );
|
|
printf( " RSA key validation: " );
|
|
if( rsa_check_pubkey( &rsa ) != 0 ||
|
rsa_check_privkey( &rsa ) != 0 )
|
{
|
printf( "failed\n" );
|
return( 1 );
|
}
|
|
printf( "passed\n PKCS#1 encryption : " );
|
|
memcpy( rsa_plaintext,
|
"\xAA\xBB\xCC\x03\x02\x01\x00\xFF\xFF\xFF\xFF\xFF" \
|
"\x11\x22\x33\x0A\x0B\x0C\xCC\xDD\xDD\xDD\xDD\xDD", PTLEN );
|
|
len = CTLEN;
|
if( rsa_pkcs1_encrypt( &rsa, rsa_plaintext, PTLEN,
|
rsa_ciphertext, &len ) != 0 )
|
{
|
printf( "failed\n" );
|
return( 1 );
|
}
|
|
printf( "passed\n PKCS#1 decryption : " );
|
|
len = sizeof( rsa_decrypted );
|
|
if( rsa_pkcs1_decrypt( &rsa, rsa_ciphertext, CTLEN,
|
rsa_decrypted, &len ) != 0 ||
|
memcmp( rsa_decrypted, rsa_plaintext, len ) != 0 )
|
{
|
printf( "failed\n" );
|
return( 1 );
|
}
|
|
printf( "passed\n" );
|
|
#if 0
|
md5_csum( rsa_plaintext, PTLEN, md5sum );
|
|
if( rsa_pkcs1_sign( &rsa, RSA_MD5, md5sum, 16,
|
rsa_ciphertext, CTLEN ) != 0 )
|
{
|
printf( "failed\n" );
|
return( 1 );
|
}
|
|
printf( "passed\n PKCS#1 sig. verify: " );
|
|
if( rsa_pkcs1_verify( &rsa, RSA_MD5, md5sum, 16,
|
rsa_ciphertext, CTLEN ) != 0 )
|
{
|
printf( "failed\n" );
|
return( 1 );
|
}
|
|
printf( "passed\n\n" );
|
#endif
|
|
rsa_free( &rsa );
|
return( 0 );
|
}
|
