/**

* \file rsa.h

*

* \brief The RSA public-key cryptosystem

*

* Copyright (C) 2006-2010, Brainspark B.V.

*

* This file is part of PolarSSL (http://www.polarssl.org)

* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>

*

* All rights reserved.

*

* This program is free software; you can redistribute it and/or modify

* it under the terms of the GNU General Public License as published by

* the Free Software Foundation; either version 2 of the License, or

* (at your option) any later version.

*

* This program is distributed in the hope that it will be useful,

* but WITHOUT ANY WARRANTY; without even the implied warranty of

* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

* GNU General Public License for more details.

*

* You should have received a copy of the GNU General Public License along

* with this program; if not, write to the Free Software Foundation, Inc.,

* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

*/

#ifndef POLARSSL_RSA_H

#define POLARSSL_RSA_H

#include "bignum.h"

/*

* RSA Error codes

*/

#define POLARSSL_ERR_RSA_BAD_INPUT_DATA -0x4080 /**< Bad input parameters to function. */

#define POLARSSL_ERR_RSA_INVALID_PADDING -0x4100 /**< Input data contains invalid padding and is rejected. */

#define POLARSSL_ERR_RSA_KEY_GEN_FAILED -0x4180 /**< Something failed during generation of a key. */

#define POLARSSL_ERR_RSA_KEY_CHECK_FAILED -0x4200 /**< Key failed to pass the libraries validity check. */

#define POLARSSL_ERR_RSA_PUBLIC_FAILED -0x4280 /**< The public key operation failed. */

#define POLARSSL_ERR_RSA_PRIVATE_FAILED -0x4300 /**< The private key operation failed. */

#define POLARSSL_ERR_RSA_VERIFY_FAILED -0x4380 /**< The PKCS#1 verification failed. */

#define POLARSSL_ERR_RSA_OUTPUT_TOO_LARGE -0x4400 /**< The output buffer for decryption is not large enough. */

#define POLARSSL_ERR_RSA_RNG_FAILED -0x4480 /**< The random generator failed to generate non-zeros. */

/*

* PKCS#1 constants

*/

#define SIG_RSA_RAW 0

#define SIG_RSA_MD2 2

#define SIG_RSA_MD4 3

#define SIG_RSA_MD5 4

#define SIG_RSA_SHA1 5

#define SIG_RSA_SHA224 14

#define SIG_RSA_SHA256 11

#define SIG_RSA_SHA384 12

#define SIG_RSA_SHA512 13

#define RSA_PUBLIC 0

#define RSA_PRIVATE 1

#define RSA_PKCS_V15 0

#define RSA_PKCS_V21 1

#define RSA_SIGN 1

#define RSA_CRYPT 2

#define ASN1_STR_CONSTRUCTED_SEQUENCE "\x30"

#define ASN1_STR_NULL "\x05"

#define ASN1_STR_OID "\x06"

#define ASN1_STR_OCTET_STRING "\x04"

#define OID_DIGEST_ALG_MDX "\x2A\x86\x48\x86\xF7\x0D\x02\x00"

#define OID_HASH_ALG_SHA1 "\x2b\x0e\x03\x02\x1a"

#define OID_HASH_ALG_SHA2X "\x60\x86\x48\x01\x65\x03\x04\x02\x00"

#define OID_ISO_MEMBER_BODIES "\x2a"

#define OID_ISO_IDENTIFIED_ORG "\x2b"

/*

* ISO Member bodies OID parts

*/

#define OID_COUNTRY_US "\x86\x48"

#define OID_RSA_DATA_SECURITY "\x86\xf7\x0d"

/*

* ISO Identified organization OID parts

*/

#define OID_OIW_SECSIG_SHA1 "\x0e\x03\x02\x1a"

/*

* DigestInfo ::= SEQUENCE {

* digestAlgorithm DigestAlgorithmIdentifier,

* digest Digest }

*

* DigestAlgorithmIdentifier ::= AlgorithmIdentifier

*

* Digest ::= OCTET STRING

*/

#define ASN1_HASH_MDX \

( \

ASN1_STR_CONSTRUCTED_SEQUENCE "\x20" \

ASN1_STR_CONSTRUCTED_SEQUENCE "\x0C" \

ASN1_STR_OID "\x08" \

OID_DIGEST_ALG_MDX \

ASN1_STR_NULL "\x00" \

ASN1_STR_OCTET_STRING "\x10" \

)

#define ASN1_HASH_SHA1 \

ASN1_STR_CONSTRUCTED_SEQUENCE "\x21" \

ASN1_STR_CONSTRUCTED_SEQUENCE "\x09" \

ASN1_STR_OID "\x05" \

OID_HASH_ALG_SHA1 \

ASN1_STR_NULL "\x00" \

ASN1_STR_OCTET_STRING "\x14"

#define ASN1_HASH_SHA1_ALT \

ASN1_STR_CONSTRUCTED_SEQUENCE "\x1F" \

ASN1_STR_CONSTRUCTED_SEQUENCE "\x07" \

ASN1_STR_OID "\x05" \

OID_HASH_ALG_SHA1 \

ASN1_STR_OCTET_STRING "\x14"

#define ASN1_HASH_SHA2X \

ASN1_STR_CONSTRUCTED_SEQUENCE "\x11" \

ASN1_STR_CONSTRUCTED_SEQUENCE "\x0d" \

ASN1_STR_OID "\x09" \

OID_HASH_ALG_SHA2X \

ASN1_STR_NULL "\x00" \

ASN1_STR_OCTET_STRING "\x00"

/**

* \brief RSA context structure

*/

typedef struct

{

int ver; /*!< always 0 */

size_t len; /*!< size(N) in chars */

mpi N; /*!< public modulus */

mpi E; /*!< public exponent */

mpi D; /*!< private exponent */

mpi P; /*!< 1st prime factor */

mpi Q; /*!< 2nd prime factor */

mpi DP; /*!< D % (P - 1) */

mpi DQ; /*!< D % (Q - 1) */

mpi QP; /*!< 1 / (Q % P) */

mpi RN; /*!< cached R^2 mod N */

mpi RP; /*!< cached R^2 mod P */

mpi RQ; /*!< cached R^2 mod Q */

int padding; /*!< RSA_PKCS_V15 for 1.5 padding and

RSA_PKCS_v21 for OAEP/PSS */

int hash_id; /*!< Hash identifier of md_type_t as

specified in the md.h header file

for the EME-OAEP and EMSA-PSS

encoding */

}

rsa_context;

#ifdef __cplusplus

extern "C" {

#endif

/**

* \brief Initialize an RSA context

*

* \param ctx RSA context to be initialized

* \param padding RSA_PKCS_V15 or RSA_PKCS_V21

* \param hash_id RSA_PKCS_V21 hash identifier

*

* \note The hash_id parameter is actually ignored

* when using RSA_PKCS_V15 padding.

*/

void rsa_init( rsa_context *ctx,

int padding,

int hash_id);

/**

* \brief Generate an RSA keypair

*

* \param ctx RSA context that will hold the key

* \param f_rng RNG function

* \param p_rng RNG parameter

* \param nbits size of the public key in bits

* \param exponent public exponent (e.g., 65537)

*

* \note rsa_init() must be called beforehand to setup

* the RSA context.

*

* \return 0 if successful, or an POLARSSL_ERR_RSA_XXX error code

*/

int rsa_gen_key( rsa_context *ctx,

int (*f_rng)(void *, unsigned char *, size_t),

void *p_rng,

unsigned int nbits, int exponent );

/**

* \brief Check a public RSA key

*

* \param ctx RSA context to be checked

*

* \return 0 if successful, or an POLARSSL_ERR_RSA_XXX error code

*/

int rsa_check_pubkey( const rsa_context *ctx );

/**

* \brief Check a private RSA key

*

* \param ctx RSA context to be checked

*

* \return 0 if successful, or an POLARSSL_ERR_RSA_XXX error code

*/

int rsa_check_privkey( const rsa_context *ctx );

/**

* \brief Do an RSA public key operation

*

* \param ctx RSA context

* \param input input buffer

* \param output output buffer

*

* \return 0 if successful, or an POLARSSL_ERR_RSA_XXX error code

*

* \note This function does NOT take care of message

* padding. Also, be sure to set input[0] = 0 or assure that

* input is smaller than N.

*

* \note The input and output buffers must be large

* enough (eg. 128 bytes if RSA-1024 is used).

*/

int rsa_public( rsa_context *ctx,

const unsigned char *input,

unsigned char *output );

/**

* \brief Do an RSA private key operation

*

* \param ctx RSA context

* \param input input buffer

* \param output output buffer

*

* \return 0 if successful, or an POLARSSL_ERR_RSA_XXX error code

*

* \note The input and output buffers must be large

* enough (eg. 128 bytes if RSA-1024 is used).

*/

int rsa_private( rsa_context *ctx,

const unsigned char *input,

unsigned char *output );

/**

* \brief Add the message padding, then do an RSA operation

*

* \param ctx RSA context

* \param f_rng RNG function (Needed for padding and PKCS#1 v2.1 encoding)

* \param p_rng RNG parameter

* \param mode RSA_PUBLIC or RSA_PRIVATE

* \param ilen contains the plaintext length

* \param input buffer holding the data to be encrypted

* \param output buffer that will hold the ciphertext

*

* \return 0 if successful, or an POLARSSL_ERR_RSA_XXX error code

*

* \note The output buffer must be as large as the size

* of ctx->N (eg. 128 bytes if RSA-1024 is used).

*/

int rsa_pkcs1_encrypt( rsa_context *ctx,

int (*f_rng)(void *, unsigned char *, size_t),

void *p_rng,

int mode, size_t ilen,

const unsigned char *input,

unsigned char *output );

/**

* \brief Do an RSA operation, then remove the message padding

*

* \param ctx RSA context

* \param mode RSA_PUBLIC or RSA_PRIVATE

* \param olen will contain the plaintext length

* \param input buffer holding the encrypted data

* \param output buffer that will hold the plaintext

* \param output_max_len maximum length of the output buffer

*

* \return 0 if successful, or an POLARSSL_ERR_RSA_XXX error code

*

* \note The output buffer must be as large as the size

* of ctx->N (eg. 128 bytes if RSA-1024 is used) otherwise

* an error is thrown.

*/

int rsa_pkcs1_decrypt( rsa_context *ctx,

int mode, size_t *olen,

const unsigned char *input,

unsigned char *output,

size_t output_max_len );

/**

* \brief Do a private RSA to sign a message digest

*

* \param ctx RSA context

* \param f_rng RNG function (Needed for PKCS#1 v2.1 encoding)

* \param p_rng RNG parameter

* \param mode RSA_PUBLIC or RSA_PRIVATE

* \param hash_id SIG_RSA_RAW, SIG_RSA_MD{2,4,5} or SIG_RSA_SHA{1,224,256,384,512}

* \param hashlen message digest length (for SIG_RSA_RAW only)

* \param hash buffer holding the message digest

* \param sig buffer that will hold the ciphertext

*

* \return 0 if the signing operation was successful,

* or an POLARSSL_ERR_RSA_XXX error code

*

* \note The "sig" buffer must be as large as the size

* of ctx->N (eg. 128 bytes if RSA-1024 is used).

*

* \note In case of PKCS#1 v2.1 encoding keep in mind that

* the hash_id in the RSA context is the one used for the

* encoding. hash_id in the function call is the type of hash

* that is encoded. According to RFC 3447 it is advised to

* keep both hashes the same.

*/

int rsa_pkcs1_sign( rsa_context *ctx,

int (*f_rng)(void *, unsigned char *, size_t),

void *p_rng,

int mode,

int hash_id,

unsigned int hashlen,

const unsigned char *hash,

unsigned char *sig );

/**

* \brief Do a public RSA and check the message digest

*

* \param ctx points to an RSA public key

* \param mode RSA_PUBLIC or RSA_PRIVATE

* \param hash_id SIG_RSA_RAW, SIG_RSA_MD{2,4,5} or SIG_RSA_SHA{1,224,256,384,512}

* \param hashlen message digest length (for SIG_RSA_RAW only)

* \param hash buffer holding the message digest

* \param sig buffer holding the ciphertext

*

* \return 0 if the verify operation was successful,

* or an POLARSSL_ERR_RSA_XXX error code

*

* \note The "sig" buffer must be as large as the size

* of ctx->N (eg. 128 bytes if RSA-1024 is used).

*

* \note In case of PKCS#1 v2.1 encoding keep in mind that

* the hash_id in the RSA context is the one used for the

* verification. hash_id in the function call is the type of hash

* that is verified. According to RFC 3447 it is advised to

* keep both hashes the same.

*/

int rsa_pkcs1_verify( rsa_context *ctx,

int mode,

int hash_id,

unsigned int hashlen,

const unsigned char *hash,

unsigned char *sig );

/**

* \brief Free the components of an RSA key

*

* \param ctx RSA Context to free

*/

void rsa_free( rsa_context *ctx );

/**

* \brief Checkup routine

*

* \return 0 if successful, or 1 if the test failed

*/

int rsa_self_test( int verbose );

#ifdef __cplusplus

}

#endif

#endif /* rsa.h */

 

 

 

 

 

 

 

/*

* The RSA public-key cryptosystem

*

* Copyright (C) 2006-2011, Brainspark B.V.

*

* This file is part of PolarSSL (http://www.polarssl.org)

* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>

*

* All rights reserved.

*

* This program is free software; you can redistribute it and/or modify

* it under the terms of the GNU General Public License as published by

* the Free Software Foundation; either version 2 of the License, or

* (at your option) any later version.

*

* This program is distributed in the hope that it will be useful,

* but WITHOUT ANY WARRANTY; without even the implied warranty of

* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

* GNU General Public License for more details.

*

* You should have received a copy of the GNU General Public License along

* with this program; if not, write to the Free Software Foundation, Inc.,

* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

*/

/*

* RSA was designed by Ron Rivest, Adi Shamir and Len Adleman.

*

* http://theory.lcs.mit.edu/~rivest/rsapaper.pdf

* http://www.cacr.math.uwaterloo.ca/hac/about/chap8.pdf

*/

#include "polarssl/config.h"

#if defined(POLARSSL_RSA_C)

#include "polarssl/rsa.h"

#include "polarssl/md.h"

#include <stdlib.h>

#include <stdio.h>

/*

* Initialize an RSA context

*/

void rsa_init( rsa_context *ctx,

int padding,

int hash_id )

{

memset( ctx, 0, sizeof( rsa_context ) );

ctx->padding = padding;

ctx->hash_id = hash_id;

}

#if defined(POLARSSL_GENPRIME)

/*

* Generate an RSA keypair

*/

int rsa_gen_key( rsa_context *ctx,

int (*f_rng)(void *, unsigned char *, size_t),

void *p_rng,

unsigned int nbits, int exponent )

{

int ret;

mpi P1, Q1, H, G;

if( f_rng == NULL || nbits < 128 || exponent < 3 )

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

mpi_init( &P1 ); mpi_init( &Q1 ); mpi_init( &H ); mpi_init( &G );

/*

* find primes P and Q with Q < P so that:

* GCD( E, (P-1)*(Q-1) ) == 1

*/

MPI_CHK( mpi_lset( &ctx->E, exponent ) );

do

{

MPI_CHK( mpi_gen_prime( &ctx->P, ( nbits + 1 ) >> 1, 0,

f_rng, p_rng ) );

MPI_CHK( mpi_gen_prime( &ctx->Q, ( nbits + 1 ) >> 1, 0,

f_rng, p_rng ) );

if( mpi_cmp_mpi( &ctx->P, &ctx->Q ) < 0 )

mpi_swap( &ctx->P, &ctx->Q );

if( mpi_cmp_mpi( &ctx->P, &ctx->Q ) == 0 )

continue;

MPI_CHK( mpi_mul_mpi( &ctx->N, &ctx->P, &ctx->Q ) );

if( mpi_msb( &ctx->N ) != nbits )

continue;

MPI_CHK( mpi_sub_int( &P1, &ctx->P, 1 ) );

MPI_CHK( mpi_sub_int( &Q1, &ctx->Q, 1 ) );

MPI_CHK( mpi_mul_mpi( &H, &P1, &Q1 ) );

MPI_CHK( mpi_gcd( &G, &ctx->E, &H ) );

}

while( mpi_cmp_int( &G, 1 ) != 0 );

/*

* D = E^-1 mod ((P-1)*(Q-1))

* DP = D mod (P - 1)

* DQ = D mod (Q - 1)

* QP = Q^-1 mod P

*/

MPI_CHK( mpi_inv_mod( &ctx->D , &ctx->E, &H ) );

MPI_CHK( mpi_mod_mpi( &ctx->DP, &ctx->D, &P1 ) );

MPI_CHK( mpi_mod_mpi( &ctx->DQ, &ctx->D, &Q1 ) );

MPI_CHK( mpi_inv_mod( &ctx->QP, &ctx->Q, &ctx->P ) );

ctx->len = ( mpi_msb( &ctx->N ) + 7 ) >> 3;

cleanup:

mpi_free( &P1 ); mpi_free( &Q1 ); mpi_free( &H ); mpi_free( &G );

if( ret != 0 )

{

rsa_free( ctx );

return( POLARSSL_ERR_RSA_KEY_GEN_FAILED + ret );

}

return( 0 );

}

#endif

/*

* Check a public RSA key

*/

int rsa_check_pubkey( const rsa_context *ctx )

{

if( !ctx->N.p || !ctx->E.p )

return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED );

if( ( ctx->N.p[0] & 1 ) == 0 ||

( ctx->E.p[0] & 1 ) == 0 )

return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED );

if( mpi_msb( &ctx->N ) < 128 ||

mpi_msb( &ctx->N ) > POLARSSL_MPI_MAX_BITS )

return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED );

if( mpi_msb( &ctx->E ) < 2 ||

mpi_msb( &ctx->E ) > 64 )

return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED );

return( 0 );

}

/*

* Check a private RSA key

*/

int rsa_check_privkey( const rsa_context *ctx )

{

int ret;

mpi PQ, DE, P1, Q1, H, I, G, G2, L1, L2;

if( ( ret = rsa_check_pubkey( ctx ) ) != 0 )

return( ret );

if( !ctx->P.p || !ctx->Q.p || !ctx->D.p )

return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED );

mpi_init( &PQ ); mpi_init( &DE ); mpi_init( &P1 ); mpi_init( &Q1 );

mpi_init( &H ); mpi_init( &I ); mpi_init( &G ); mpi_init( &G2 );

mpi_init( &L1 ); mpi_init( &L2 );

MPI_CHK( mpi_mul_mpi( &PQ, &ctx->P, &ctx->Q ) );

MPI_CHK( mpi_mul_mpi( &DE, &ctx->D, &ctx->E ) );

MPI_CHK( mpi_sub_int( &P1, &ctx->P, 1 ) );

MPI_CHK( mpi_sub_int( &Q1, &ctx->Q, 1 ) );

MPI_CHK( mpi_mul_mpi( &H, &P1, &Q1 ) );

MPI_CHK( mpi_gcd( &G, &ctx->E, &H ) );

MPI_CHK( mpi_gcd( &G2, &P1, &Q1 ) );

MPI_CHK( mpi_div_mpi( &L1, &L2, &H, &G2 ) );

MPI_CHK( mpi_mod_mpi( &I, &DE, &L1 ) );

/*

* Check for a valid PKCS1v2 private key

*/

if( mpi_cmp_mpi( &PQ, &ctx->N ) != 0 ||

mpi_cmp_int( &L2, 0 ) != 0 ||

mpi_cmp_int( &I, 1 ) != 0 ||

mpi_cmp_int( &G, 1 ) != 0 )

{

ret = POLARSSL_ERR_RSA_KEY_CHECK_FAILED;

}

cleanup:

mpi_free( &PQ ); mpi_free( &DE ); mpi_free( &P1 ); mpi_free( &Q1 );

mpi_free( &H ); mpi_free( &I ); mpi_free( &G ); mpi_free( &G2 );

mpi_free( &L1 ); mpi_free( &L2 );

if( ret == POLARSSL_ERR_RSA_KEY_CHECK_FAILED )

return( ret );

if( ret != 0 )

return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED + ret );

return( 0 );

}

/*

* Do an RSA public key operation

*/

int rsa_public( rsa_context *ctx,

const unsigned char *input,

unsigned char *output )

{

int ret;

size_t olen;

mpi T;

mpi_init( &T );

MPI_CHK( mpi_read_binary( &T, input, ctx->len ) );

if( mpi_cmp_mpi( &T, &ctx->N ) >= 0 )

{

mpi_free( &T );

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

}

olen = ctx->len;

MPI_CHK( mpi_exp_mod( &T, &T, &ctx->E, &ctx->N, &ctx->RN ) );

MPI_CHK( mpi_write_binary( &T, output, olen ) );

cleanup:

mpi_free( &T );

if( ret != 0 )

return( POLARSSL_ERR_RSA_PUBLIC_FAILED + ret );

return( 0 );

}

/*

* Do an RSA private key operation

*/

int rsa_private( rsa_context *ctx,

const unsigned char *input,

unsigned char *output )

{

int ret;

size_t olen;

mpi T, T1, T2;

mpi_init( &T ); mpi_init( &T1 ); mpi_init( &T2 );

MPI_CHK( mpi_read_binary( &T, input, ctx->len ) );

if( mpi_cmp_mpi( &T, &ctx->N ) >= 0 )

{

mpi_free( &T );

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

}

#if defined(POLARSSL_RSA_NO_CRT)

MPI_CHK( mpi_exp_mod( &T, &T, &ctx->D, &ctx->N, &ctx->RN ) );

#else

/*

* faster decryption using the CRT

*

* T1 = input ^ dP mod P

* T2 = input ^ dQ mod Q

*/

MPI_CHK( mpi_exp_mod( &T1, &T, &ctx->DP, &ctx->P, &ctx->RP ) );

MPI_CHK( mpi_exp_mod( &T2, &T, &ctx->DQ, &ctx->Q, &ctx->RQ ) );

/*

* T = (T1 - T2) * (Q^-1 mod P) mod P

*/

MPI_CHK( mpi_sub_mpi( &T, &T1, &T2 ) );

MPI_CHK( mpi_mul_mpi( &T1, &T, &ctx->QP ) );

MPI_CHK( mpi_mod_mpi( &T, &T1, &ctx->P ) );

/*

* output = T2 + T * Q

*/

MPI_CHK( mpi_mul_mpi( &T1, &T, &ctx->Q ) );

MPI_CHK( mpi_add_mpi( &T, &T2, &T1 ) );

#endif

olen = ctx->len;

MPI_CHK( mpi_write_binary( &T, output, olen ) );

cleanup:

mpi_free( &T ); mpi_free( &T1 ); mpi_free( &T2 );

if( ret != 0 )

return( POLARSSL_ERR_RSA_PRIVATE_FAILED + ret );

return( 0 );

}

#if defined(POLARSSL_PKCS1_V21)

/**

* Generate and apply the MGF1 operation (from PKCS#1 v2.1) to a buffer.

*

* \param dst buffer to mask

* \param dlen length of destination buffer

* \param src source of the mask generation

* \param slen length of the source buffer

* \param md_ctx message digest context to use

*/

static void mgf_mask( unsigned char *dst, size_t dlen, unsigned char *src, size_t slen,

md_context_t *md_ctx )

{

unsigned char mask[POLARSSL_MD_MAX_SIZE];

unsigned char counter[4];

unsigned char *p;

unsigned int hlen;

size_t i, use_len;

memset( mask, 0, POLARSSL_MD_MAX_SIZE );

memset( counter, 0, 4 );

hlen = md_ctx->md_info->size;

// Generate and apply dbMask

//

p = dst;

while( dlen > 0 )

{

use_len = hlen;

if( dlen < hlen )

use_len = dlen;

md_starts( md_ctx );

md_update( md_ctx, src, slen );

md_update( md_ctx, counter, 4 );

md_finish( md_ctx, mask );

for( i = 0; i < use_len; ++i )

*p++ ^= mask[i];

counter[3]++;

dlen -= use_len;

}

}

#endif

/*

* Add the message padding, then do an RSA operation

*/

int rsa_pkcs1_encrypt( rsa_context *ctx,

int (*f_rng)(void *, unsigned char *, size_t),

void *p_rng,

int mode, size_t ilen,

const unsigned char *input,

unsigned char *output )

{

size_t nb_pad, olen;

int ret;

unsigned char *p = output;

#if defined(POLARSSL_PKCS1_V21)

unsigned int hlen;

const md_info_t *md_info;

md_context_t md_ctx;

#endif

olen = ctx->len;

if( f_rng == NULL )

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

switch( ctx->padding )

{

case RSA_PKCS_V15:

if( olen < ilen + 11 )

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

nb_pad = olen - 3 - ilen;

*p++ = 0;

*p++ = RSA_CRYPT;

while( nb_pad-- > 0 )

{

int rng_dl = 100;

do {

ret = f_rng( p_rng, p, 1 );

} while( *p == 0 && --rng_dl && ret == 0 );

// Check if RNG failed to generate data

//

if( rng_dl == 0 || ret != 0)

return POLARSSL_ERR_RSA_RNG_FAILED + ret;

p++;

}

*p++ = 0;

memcpy( p, input, ilen );

break;

#if defined(POLARSSL_PKCS1_V21)

case RSA_PKCS_V21:

md_info = md_info_from_type( ctx->hash_id );

if( md_info == NULL )

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

hlen = md_get_size( md_info );

if( olen < ilen + 2 * hlen + 2 || f_rng == NULL )

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

memset( output, 0, olen );

memset( &md_ctx, 0, sizeof( md_context_t ) );

md_init_ctx( &md_ctx, md_info );

*p++ = 0;

// Generate a random octet string seed

//

if( ( ret = f_rng( p_rng, p, hlen ) ) != 0 )

return( POLARSSL_ERR_RSA_RNG_FAILED + ret );

p += hlen;

// Construct DB

//

md( md_info, p, 0, p );

p += hlen;

p += olen - 2 * hlen - 2 - ilen;

*p++ = 1;

memcpy( p, input, ilen );

// maskedDB: Apply dbMask to DB

//

mgf_mask( output + hlen + 1, olen - hlen - 1, output + 1, hlen,

&md_ctx );

// maskedSeed: Apply seedMask to seed

//

mgf_mask( output + 1, hlen, output + hlen + 1, olen - hlen - 1,

&md_ctx );

break;

#endif

default:

return( POLARSSL_ERR_RSA_INVALID_PADDING );

}

return( ( mode == RSA_PUBLIC )

? rsa_public( ctx, output, output )

: rsa_private( ctx, output, output ) );

}

/*

* Do an RSA operation, then remove the message padding

*/

int rsa_pkcs1_decrypt( rsa_context *ctx,

int mode, size_t *olen,

const unsigned char *input,

unsigned char *output,

size_t output_max_len)

{

int ret;

size_t ilen;

unsigned char *p;

unsigned char buf[1024];

#if defined(POLARSSL_PKCS1_V21)

unsigned char lhash[POLARSSL_MD_MAX_SIZE];

unsigned int hlen;

const md_info_t *md_info;

md_context_t md_ctx;

#endif

ilen = ctx->len;

if( ilen < 16 || ilen > sizeof( buf ) )

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

ret = ( mode == RSA_PUBLIC )

? rsa_public( ctx, input, buf )

: rsa_private( ctx, input, buf );

if( ret != 0 )

return( ret );

p = buf;

switch( ctx->padding )

{

case RSA_PKCS_V15:

if( *p++ != 0 || *p++ != RSA_CRYPT )

return( POLARSSL_ERR_RSA_INVALID_PADDING );

while( *p != 0 )

{

if( p >= buf + ilen - 1 )

return( POLARSSL_ERR_RSA_INVALID_PADDING );

p++;

}

p++;

break;

#if defined(POLARSSL_PKCS1_V21)

case RSA_PKCS_V21:

if( *p++ != 0 )

return( POLARSSL_ERR_RSA_INVALID_PADDING );

md_info = md_info_from_type( ctx->hash_id );

if( md_info == NULL )

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

hlen = md_get_size( md_info );

memset( &md_ctx, 0, sizeof( md_context_t ) );

md_init_ctx( &md_ctx, md_info );

// Generate lHash

//

md( md_info, lhash, 0, lhash );

// seed: Apply seedMask to maskedSeed

//

mgf_mask( buf + 1, hlen, buf + hlen + 1, ilen - hlen - 1,

&md_ctx );

// DB: Apply dbMask to maskedDB

//

mgf_mask( buf + hlen + 1, ilen - hlen - 1, buf + 1, hlen,

&md_ctx );

p += hlen;

// Check validity

//

if( memcmp( lhash, p, hlen ) != 0 )

return( POLARSSL_ERR_RSA_INVALID_PADDING );

p += hlen;

while( *p == 0 && p < buf + ilen )

p++;

if( p == buf + ilen )

return( POLARSSL_ERR_RSA_INVALID_PADDING );

if( *p++ != 0x01 )

return( POLARSSL_ERR_RSA_INVALID_PADDING );

break;

#endif

default:

return( POLARSSL_ERR_RSA_INVALID_PADDING );

}

if (ilen - (p - buf) > output_max_len)

return( POLARSSL_ERR_RSA_OUTPUT_TOO_LARGE );

*olen = ilen - (p - buf);

memcpy( output, p, *olen );

return( 0 );

}

/*

* Do an RSA operation to sign the message digest

*/

int rsa_pkcs1_sign( rsa_context *ctx,

int (*f_rng)(void *, unsigned char *, size_t),

void *p_rng,

int mode,

int hash_id,

unsigned int hashlen,

const unsigned char *hash,

unsigned char *sig )

{

size_t nb_pad, olen;

unsigned char *p = sig;

#if defined(POLARSSL_PKCS1_V21)

unsigned char salt[POLARSSL_MD_MAX_SIZE];

unsigned int slen, hlen, offset = 0;

int ret;

size_t msb;

const md_info_t *md_info;

md_context_t md_ctx;

#else

(void) f_rng;

(void) p_rng;

#endif

olen = ctx->len;

switch( ctx->padding )

{

case RSA_PKCS_V15:

switch( hash_id )

{

case SIG_RSA_RAW:

nb_pad = olen - 3 - hashlen;

break;

case SIG_RSA_MD2:

case SIG_RSA_MD4:

case SIG_RSA_MD5:

nb_pad = olen - 3 - 34;

break;

case SIG_RSA_SHA1:

nb_pad = olen - 3 - 35;

break;

case SIG_RSA_SHA224:

nb_pad = olen - 3 - 47;

break;

case SIG_RSA_SHA256:

nb_pad = olen - 3 - 51;

break;

case SIG_RSA_SHA384:

nb_pad = olen - 3 - 67;

break;

case SIG_RSA_SHA512:

nb_pad = olen - 3 - 83;

break;

default:

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

}

if( nb_pad < 8 )

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

*p++ = 0;

*p++ = RSA_SIGN;

memset( p, 0xFF, nb_pad );

p += nb_pad;

*p++ = 0;

switch( hash_id )

{

case SIG_RSA_RAW:

memcpy( p, hash, hashlen );

break;

case SIG_RSA_MD2:

memcpy( p, ASN1_HASH_MDX, 18 );

memcpy( p + 18, hash, 16 );

p[13] = 2; break;

case SIG_RSA_MD4:

memcpy( p, ASN1_HASH_MDX, 18 );

memcpy( p + 18, hash, 16 );

p[13] = 4; break;

case SIG_RSA_MD5:

memcpy( p, ASN1_HASH_MDX, 18 );

memcpy( p + 18, hash, 16 );

p[13] = 5; break;

case SIG_RSA_SHA1:

memcpy( p, ASN1_HASH_SHA1, 15 );

memcpy( p + 15, hash, 20 );

break;

case SIG_RSA_SHA224:

memcpy( p, ASN1_HASH_SHA2X, 19 );

memcpy( p + 19, hash, 28 );

p[1] += 28; p[14] = 4; p[18] += 28; break;

case SIG_RSA_SHA256:

memcpy( p, ASN1_HASH_SHA2X, 19 );

memcpy( p + 19, hash, 32 );

p[1] += 32; p[14] = 1; p[18] += 32; break;

case SIG_RSA_SHA384:

memcpy( p, ASN1_HASH_SHA2X, 19 );

memcpy( p + 19, hash, 48 );

p[1] += 48; p[14] = 2; p[18] += 48; break;

case SIG_RSA_SHA512:

memcpy( p, ASN1_HASH_SHA2X, 19 );

memcpy( p + 19, hash, 64 );

p[1] += 64; p[14] = 3; p[18] += 64; break;

default:

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

}

break;

#if defined(POLARSSL_PKCS1_V21)

case RSA_PKCS_V21:

if( f_rng == NULL )

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

switch( hash_id )

{

case SIG_RSA_MD2:

case SIG_RSA_MD4:

case SIG_RSA_MD5:

hashlen = 16;

break;

case SIG_RSA_SHA1:

hashlen = 20;

break;

case SIG_RSA_SHA224:

hashlen = 28;

break;

case SIG_RSA_SHA256:

hashlen = 32;

break;

case SIG_RSA_SHA384:

hashlen = 48;

break;

case SIG_RSA_SHA512:

hashlen = 64;

break;

default:

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

}

md_info = md_info_from_type( ctx->hash_id );

if( md_info == NULL )

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

hlen = md_get_size( md_info );

slen = hlen;

memset( sig, 0, olen );

memset( &md_ctx, 0, sizeof( md_context_t ) );

md_init_ctx( &md_ctx, md_info );

msb = mpi_msb( &ctx->N ) - 1;

// Generate salt of length slen

//

if( ( ret = f_rng( p_rng, salt, slen ) ) != 0 )

return( POLARSSL_ERR_RSA_RNG_FAILED + ret );

// Note: EMSA-PSS encoding is over the length of N - 1 bits

//

msb = mpi_msb( &ctx->N ) - 1;

p += olen - hlen * 2 - 2;

*p++ = 0x01;

memcpy( p, salt, slen );

p += slen;

// Generate H = Hash( M' )

//

md_starts( &md_ctx );

md_update( &md_ctx, p, 8 );

md_update( &md_ctx, hash, hashlen );

md_update( &md_ctx, salt, slen );

md_finish( &md_ctx, p );

// Compensate for boundary condition when applying mask

//

if( msb % 8 == 0 )

offset = 1;

// maskedDB: Apply dbMask to DB

//

mgf_mask( sig + offset, olen - hlen - 1 - offset, p, hlen, &md_ctx );

msb = mpi_msb( &ctx->N ) - 1;

sig[0] &= 0xFF >> ( olen * 8 - msb );

p += hlen;

*p++ = 0xBC;

break;

#endif

default:

return( POLARSSL_ERR_RSA_INVALID_PADDING );

}

return( ( mode == RSA_PUBLIC )

? rsa_public( ctx, sig, sig )

: rsa_private( ctx, sig, sig ) );

}

/*

* Do an RSA operation and check the message digest

*/

int rsa_pkcs1_verify( rsa_context *ctx,

int mode,

int hash_id,

unsigned int hashlen,

const unsigned char *hash,

unsigned char *sig )

{

int ret;

size_t len, siglen;

unsigned char *p, c;

unsigned char buf[1024];

#if defined(POLARSSL_PKCS1_V21)

unsigned char result[POLARSSL_MD_MAX_SIZE];

unsigned char zeros[8];

unsigned int hlen;

size_t slen, msb;

const md_info_t *md_info;

md_context_t md_ctx;

#endif

siglen = ctx->len;

if( siglen < 16 || siglen > sizeof( buf ) )

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

ret = ( mode == RSA_PUBLIC )

? rsa_public( ctx, sig, buf )

: rsa_private( ctx, sig, buf );

if( ret != 0 )

return( ret );

p = buf;

switch( ctx->padding )

{

case RSA_PKCS_V15:

if( *p++ != 0 || *p++ != RSA_SIGN )

return( POLARSSL_ERR_RSA_INVALID_PADDING );

while( *p != 0 )

{

if( p >= buf + siglen - 1 || *p != 0xFF )

return( POLARSSL_ERR_RSA_INVALID_PADDING );

p++;

}

p++;

len = siglen - ( p - buf );

if( len == 33 && hash_id == SIG_RSA_SHA1 )

{

if( memcmp( p, ASN1_HASH_SHA1_ALT, 13 ) == 0 &&

memcmp( p + 13, hash, 20 ) == 0 )

return( 0 );

else

return( POLARSSL_ERR_RSA_VERIFY_FAILED );

}

if( len == 34 )

{

c = p[13];

p[13] = 0;

if( memcmp( p, ASN1_HASH_MDX, 18 ) != 0 )

return( POLARSSL_ERR_RSA_VERIFY_FAILED );

if( ( c == 2 && hash_id == SIG_RSA_MD2 ) ||

( c == 4 && hash_id == SIG_RSA_MD4 ) ||

( c == 5 && hash_id == SIG_RSA_MD5 ) )

{

if( memcmp( p + 18, hash, 16 ) == 0 )

return( 0 );

else

return( POLARSSL_ERR_RSA_VERIFY_FAILED );

}

}

if( len == 35 && hash_id == SIG_RSA_SHA1 )

{

if( memcmp( p, ASN1_HASH_SHA1, 15 ) == 0 &&

memcmp( p + 15, hash, 20 ) == 0 )

return( 0 );

else

return( POLARSSL_ERR_RSA_VERIFY_FAILED );

}

if( ( len == 19 + 28 && p[14] == 4 && hash_id == SIG_RSA_SHA224 ) ||

( len == 19 + 32 && p[14] == 1 && hash_id == SIG_RSA_SHA256 ) ||

( len == 19 + 48 && p[14] == 2 && hash_id == SIG_RSA_SHA384 ) ||

( len == 19 + 64 && p[14] == 3 && hash_id == SIG_RSA_SHA512 ) )

{

c = p[1] - 17;

p[1] = 17;

p[14] = 0;

if( p[18] == c &&

memcmp( p, ASN1_HASH_SHA2X, 18 ) == 0 &&

memcmp( p + 19, hash, c ) == 0 )

return( 0 );

else

return( POLARSSL_ERR_RSA_VERIFY_FAILED );

}

if( len == hashlen && hash_id == SIG_RSA_RAW )

{

if( memcmp( p, hash, hashlen ) == 0 )

return( 0 );

else

return( POLARSSL_ERR_RSA_VERIFY_FAILED );

}

break;

#if defined(POLARSSL_PKCS1_V21)

case RSA_PKCS_V21:

if( buf[siglen - 1] != 0xBC )

return( POLARSSL_ERR_RSA_INVALID_PADDING );

switch( hash_id )

{

case SIG_RSA_MD2:

case SIG_RSA_MD4:

case SIG_RSA_MD5:

hashlen = 16;

break;

case SIG_RSA_SHA1:

hashlen = 20;

break;

case SIG_RSA_SHA224:

hashlen = 28;

break;

case SIG_RSA_SHA256:

hashlen = 32;

break;

case SIG_RSA_SHA384:

hashlen = 48;

break;

case SIG_RSA_SHA512:

hashlen = 64;

break;

default:

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

}

md_info = md_info_from_type( ctx->hash_id );

if( md_info == NULL )

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

hlen = md_get_size( md_info );

slen = siglen - hlen - 1;

memset( &md_ctx, 0, sizeof( md_context_t ) );

memset( zeros, 0, 8 );

md_init_ctx( &md_ctx, md_info );

// Note: EMSA-PSS verification is over the length of N - 1 bits

//

msb = mpi_msb( &ctx->N ) - 1;

// Compensate for boundary condition when applying mask

//

if( msb % 8 == 0 )

{

p++;

siglen -= 1;

}

if( buf[0] >> ( 8 - siglen * 8 + msb ) )

return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );

mgf_mask( p, siglen - hlen - 1, p + siglen - hlen - 1, hlen, &md_ctx );

buf[0] &= 0xFF >> ( siglen * 8 - msb );

while( *p == 0 && p < buf + siglen )

p++;

if( p == buf + siglen )

return( POLARSSL_ERR_RSA_INVALID_PADDING );

if( *p++ != 0x01 )

return( POLARSSL_ERR_RSA_INVALID_PADDING );

slen -= p - buf;

// Generate H = Hash( M' )

//

md_starts( &md_ctx );

md_update( &md_ctx, zeros, 8 );

md_update( &md_ctx, hash, hashlen );

md_update( &md_ctx, p, slen );

md_finish( &md_ctx, result );

if( memcmp( p + slen, result, hlen ) == 0 )

return( 0 );

else

return( POLARSSL_ERR_RSA_VERIFY_FAILED );

#endif

default:

return( POLARSSL_ERR_RSA_INVALID_PADDING );

}

return( POLARSSL_ERR_RSA_INVALID_PADDING );

}

/*

* Free the components of an RSA key

*/

void rsa_free( rsa_context *ctx )

{

mpi_free( &ctx->RQ ); mpi_free( &ctx->RP ); mpi_free( &ctx->RN );

mpi_free( &ctx->QP ); mpi_free( &ctx->DQ ); mpi_free( &ctx->DP );

mpi_free( &ctx->Q ); mpi_free( &ctx->P ); mpi_free( &ctx->D );

mpi_free( &ctx->E ); mpi_free( &ctx->N );

}

#if defined(POLARSSL_SELF_TEST)

#include "polarssl/sha1.h"

/*

* Example RSA-1024 keypair, for test purposes

*/

#define KEY_LEN 128

#define RSA_N "9292758453063D803DD603D5E777D788" \

"8ED1D5BF35786190FA2F23EBC0848AEA" \

"DDA92CA6C3D80B32C4D109BE0F36D6AE" \

"7130B9CED7ACDF54CFC7555AC14EEBAB" \

"93A89813FBF3C4F8066D2D800F7C38A8" \

"1AE31942917403FF4946B0A83D3D3E05" \

"EE57C6F5F5606FB5D4BC6CD34EE0801A" \

"5E94BB77B07507233A0BC7BAC8F90F79"

#define RSA_E "10001"

#define RSA_D "24BF6185468786FDD303083D25E64EFC" \

"66CA472BC44D253102F8B4A9D3BFA750" \

"91386C0077937FE33FA3252D28855837" \

"AE1B484A8A9A45F7EE8C0C634F99E8CD" \

"DF79C5CE07EE72C7F123142198164234" \

"CABB724CF78B8173B9F880FC86322407" \

"AF1FEDFDDE2BEB674CA15F3E81A1521E" \

"071513A1E85B5DFA031F21ECAE91A34D"

#define RSA_P "C36D0EB7FCD285223CFB5AABA5BDA3D8" \

"2C01CAD19EA484A87EA4377637E75500" \

"FCB2005C5C7DD6EC4AC023CDA285D796" \

"C3D9E75E1EFC42488BB4F1D13AC30A57"

#define RSA_Q "C000DF51A7C77AE8D7C7370C1FF55B69" \

"E211C2B9E5DB1ED0BF61D0D9899620F4" \

"910E4168387E3C30AA1E00C339A79508" \

"8452DD96A9A5EA5D9DCA68DA636032AF"

#define RSA_DP "C1ACF567564274FB07A0BBAD5D26E298" \

"3C94D22288ACD763FD8E5600ED4A702D" \

"F84198A5F06C2E72236AE490C93F07F8" \

"3CC559CD27BC2D1CA488811730BB5725"

#define RSA_DQ "4959CBF6F8FEF750AEE6977C155579C7" \

"D8AAEA56749EA28623272E4F7D0592AF" \

"7C1F1313CAC9471B5C523BFE592F517B" \

"407A1BD76C164B93DA2D32A383E58357"

#define RSA_QP "9AE7FBC99546432DF71896FC239EADAE" \

"F38D18D2B2F0E2DD275AA977E2BF4411" \

"F5A3B2A5D33605AEBBCCBA7FEB9F2D2F" \

"A74206CEC169D74BF5A8C50D6F48EA08"

#define PT_LEN 24

#define RSA_PT "\xAA\xBB\xCC\x03\x02\x01\x00\xFF\xFF\xFF\xFF\xFF" \

"\x11\x22\x33\x0A\x0B\x0C\xCC\xDD\xDD\xDD\xDD\xDD"

static int myrand( void *rng_state, unsigned char *output, size_t len )

{

size_t i;

if( rng_state != NULL )

rng_state = NULL;

for( i = 0; i < len; ++i )

output[i] = rand();

return( 0 );

}

/*

* Checkup routine

*/

int rsa_self_test( int verbose )

{

size_t len;

rsa_context rsa;

unsigned char rsa_plaintext[PT_LEN];

unsigned char rsa_decrypted[PT_LEN];

unsigned char rsa_ciphertext[KEY_LEN];

#if defined(POLARSSL_SHA1_C)

unsigned char sha1sum[20];

#endif

rsa_init( &rsa, RSA_PKCS_V15, 0 );

rsa.len = KEY_LEN;

mpi_read_string( &rsa.N , 16, RSA_N );

mpi_read_string( &rsa.E , 16, RSA_E );

mpi_read_string( &rsa.D , 16, RSA_D );

mpi_read_string( &rsa.P , 16, RSA_P );

mpi_read_string( &rsa.Q , 16, RSA_Q );

mpi_read_string( &rsa.DP, 16, RSA_DP );

mpi_read_string( &rsa.DQ, 16, RSA_DQ );

mpi_read_string( &rsa.QP, 16, RSA_QP );

if( verbose != 0 )

printf( " RSA key validation: " );

if( rsa_check_pubkey( &rsa ) != 0 ||

rsa_check_privkey( &rsa ) != 0 )

{

if( verbose != 0 )

printf( "failed\n" );

return( 1 );

}

if( verbose != 0 )

printf( "passed\n PKCS#1 encryption : " );

memcpy( rsa_plaintext, RSA_PT, PT_LEN );

if( rsa_pkcs1_encrypt( &rsa, &myrand, NULL, RSA_PUBLIC, PT_LEN,

rsa_plaintext, rsa_ciphertext ) != 0 )

{

if( verbose != 0 )

printf( "failed\n" );

return( 1 );

}

if( verbose != 0 )

printf( "passed\n PKCS#1 decryption : " );

if( rsa_pkcs1_decrypt( &rsa, RSA_PRIVATE, &len,

rsa_ciphertext, rsa_decrypted,

sizeof(rsa_decrypted) ) != 0 )

{

if( verbose != 0 )

printf( "failed\n" );

return( 1 );

}

if( memcmp( rsa_decrypted, rsa_plaintext, len ) != 0 )

{

if( verbose != 0 )

printf( "failed\n" );

return( 1 );

}

#if defined(POLARSSL_SHA1_C)

if( verbose != 0 )

printf( "passed\n PKCS#1 data sign : " );

sha1( rsa_plaintext, PT_LEN, sha1sum );

if( rsa_pkcs1_sign( &rsa, NULL, NULL, RSA_PRIVATE, SIG_RSA_SHA1, 20,

sha1sum, rsa_ciphertext ) != 0 )

{

if( verbose != 0 )

printf( "failed\n" );

return( 1 );

}

if( verbose != 0 )

printf( "passed\n PKCS#1 sig. verify: " );

if( rsa_pkcs1_verify( &rsa, RSA_PUBLIC, SIG_RSA_SHA1, 20,

sha1sum, rsa_ciphertext ) != 0 )

{

if( verbose != 0 )

printf( "failed\n" );

return( 1 );

}

if( verbose != 0 )

printf( "passed\n\n" );

#endif /* POLARSSL_SHA1_C */

rsa_free( &rsa );

return( 0 );

}

#endif

#endif