rsa.c

一个用纯C写的RSA_SHA1数字签名库

            return( XYSSL_ERR_RSA_INVALID_PADDING );
    }

    *olen = ilen - (int)(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 mode,
                    int hash_id,
                    int hashlen,
                    unsigned char *hash,
                    unsigned char *sig )
{
    int nb_pad, olen;
    unsigned char *p = sig;

    olen = ctx->len;

    switch( ctx->padding )
    {
        case RSA_PKCS_V15:

            switch( hash_id )
            {
                case RSA_RAW:
                    nb_pad = olen - 3 - hashlen;
                    break;

                case RSA_MD2:
                case RSA_MD4:
                case RSA_MD5:
                    nb_pad = olen - 3 - 34;
                    break;

                case RSA_SHA1:
                    nb_pad = olen - 3 - 35;
                    break;

                default:
                    return( XYSSL_ERR_RSA_BAD_INPUT_DATA );
            }

            if( nb_pad < 8 )
                return( XYSSL_ERR_RSA_BAD_INPUT_DATA );

            *p++ = 0;
            *p++ = RSA_SIGN;
            memset( p, 0xFF, nb_pad );
            p += nb_pad;
            *p++ = 0;
            break;

        default:

            return( XYSSL_ERR_RSA_INVALID_PADDING );
    }

    switch( hash_id )
    {
        case RSA_RAW:
            memcpy( p, hash, hashlen );
            break;

        case RSA_MD2:
            memcpy( p, ASN1_HASH_MDX, 18 );
            memcpy( p + 18, hash, 16 );
            p[13] = 2; break;

        case RSA_MD4:
            memcpy( p, ASN1_HASH_MDX, 18 );
            memcpy( p + 18, hash, 16 );
            p[13] = 4; break;

        case RSA_MD5:
            memcpy( p, ASN1_HASH_MDX, 18 );
            memcpy( p + 18, hash, 16 );
            p[13] = 5; break;

        case RSA_SHA1:
            memcpy( p, ASN1_HASH_SHA1, 15 );
            memcpy( p + 15, hash, 20 );
            break;

        default:
            return( XYSSL_ERR_RSA_BAD_INPUT_DATA );
    }

    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,
                      int hashlen,
                      unsigned char *hash,
                      unsigned char *sig )
{
    int ret, len, siglen;
    unsigned char *p, c;
    unsigned char buf[512];

    siglen = ctx->len;

    if( siglen < 16 || siglen > (int) sizeof( buf ) )
        return( XYSSL_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( XYSSL_ERR_RSA_INVALID_PADDING );

            while( *p != 0 )
            {
                if( p >= buf + siglen - 1 || *p != 0xFF )
                    return( XYSSL_ERR_RSA_INVALID_PADDING );
                p++;
            }
            p++;
            break;

        default:

            return( XYSSL_ERR_RSA_INVALID_PADDING );
    }

    len = siglen - (int)( p - buf );

    if( len == 34 )
    {
        c = p[13];
        p[13] = 0;

        if( memcmp( p, ASN1_HASH_MDX, 18 ) != 0 )
            return( XYSSL_ERR_RSA_VERIFY_FAILED );

        if( ( c == 2 && hash_id == RSA_MD2 ) ||
            ( c == 4 && hash_id == RSA_MD4 ) ||
            ( c == 5 && hash_id == RSA_MD5 ) )
        {
            if( memcmp( p + 18, hash, 16 ) == 0 ) 
                return( 0 );
            else
                return( XYSSL_ERR_RSA_VERIFY_FAILED );
        }
    }

    if( len == 35 && hash_id == RSA_SHA1 )
    {
        if( memcmp( p, ASN1_HASH_SHA1, 15 ) == 0 &&
            memcmp( p + 15, hash, 20 ) == 0 )
            return( 0 );
        else
            return( XYSSL_ERR_RSA_VERIFY_FAILED );
    }

    if( len == hashlen && hash_id == RSA_RAW )
    {
        if( memcmp( p, hash, hashlen ) == 0 )
            return( 0 );
        else
            return( XYSSL_ERR_RSA_VERIFY_FAILED );
    }

    return( XYSSL_ERR_RSA_INVALID_PADDING );
}

/*
 * Free the components of an RSA key
 */
void rsa_free( rsa_context *ctx )
{
    mpi_free( &ctx->RQ, &ctx->RP, &ctx->RN,
              &ctx->QP, &ctx->DQ, &ctx->DP,
              &ctx->Q,  &ctx->P,  &ctx->D,
              &ctx->E,  &ctx->N,  NULL );
}

#if defined(XYSSL_SELF_TEST)

#include "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"

/*
 * Checkup routine
 */
int rsa_self_test( int verbose )
{
    int len;
    rsa_context rsa;
    unsigned char sha1sum[20];
    unsigned char rsa_plaintext[PT_LEN];
    unsigned char rsa_decrypted[PT_LEN];
    unsigned char rsa_ciphertext[KEY_LEN];

    memset( &rsa, 0, sizeof( rsa_context ) );

    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, 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 ) != 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( verbose != 0 )
        printf( "passed\n  PKCS#1 data sign  : " );

    sha1( rsa_plaintext, PT_LEN, sha1sum );

    if( rsa_pkcs1_sign( &rsa, RSA_PRIVATE, 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, RSA_SHA1, 20,
                          sha1sum, rsa_ciphertext ) != 0 )
    {
        if( verbose != 0 )
            printf( "failed\n" );

        return( 1 );
    }

    if( verbose != 0 )
        printf( "passed\n\n" );

    rsa_free( &rsa );

    return( 0 );
}

#endif

#endif