aessmall.c

使用visual studio 2005 开发的开源文件、磁盘加密软件。这是6.1a版。加密自己资料的好工具。也是学习的优秀范本。结成了众多加密算法。

        }
#else
        {   uint_8t s2[N_BLOCK];
            mix_sub_columns( s2, s1 );
            copy_and_key( s1, s2, ctx->ksch + r * N_BLOCK);
        }
#endif
        shift_sub_rows( s1 );
        copy_and_key( out, s1, ctx->ksch + r * N_BLOCK );
    }
    else
        return -1;
    return 0;
}

#endif

#if defined( AES_DEC_PREKEYED )

/*  Decrypt a single block of 16 bytes */

return_type aes_decrypt( const unsigned char in[N_BLOCK], unsigned char out[N_BLOCK], const aes_context ctx[1] )
{
    if( ctx->rnd )
    {
        uint_8t s1[N_BLOCK], r;
        copy_and_key( s1, in, ctx->ksch + ctx->rnd * N_BLOCK );
        inv_shift_sub_rows( s1 );

        for( r = ctx->rnd ; --r ; )
#if defined( VERSION_1 )
        {
            add_round_key( s1, ctx->ksch + r * N_BLOCK );
            inv_mix_sub_columns( s1 );
        }
#else
        {   uint_8t s2[N_BLOCK];
            copy_and_key( s2, s1, ctx->ksch + r * N_BLOCK );
            inv_mix_sub_columns( s1, s2 );
        }
#endif
        copy_and_key( out, s1, ctx->ksch );
    }
    else
        return -1;
    return 0;
}

#endif

#if defined( AES_ENC_128_OTFK )

/*  The 'on the fly' encryption key update for for 128 bit keys */

static void update_encrypt_key_128( uint_8t k[N_BLOCK], uint_8t *rc )
{   uint_8t cc;

    k[0] ^= s_box[k[13]] ^ *rc;
    k[1] ^= s_box[k[14]];
    k[2] ^= s_box[k[15]];
    k[3] ^= s_box[k[12]];
    *rc = f2( *rc );

    for(cc = 4; cc < 16; cc += 4 )
    {
        k[cc + 0] ^= k[cc - 4];
        k[cc + 1] ^= k[cc - 3];
        k[cc + 2] ^= k[cc - 2];
        k[cc + 3] ^= k[cc - 1];
    }
}

/*  Encrypt a single block of 16 bytes with 'on the fly' 128 bit keying */

void aes_encrypt_128( const unsigned char in[N_BLOCK], unsigned char out[N_BLOCK],
                     const unsigned char key[N_BLOCK], unsigned char o_key[N_BLOCK] )
{   uint_8t s1[N_BLOCK], r, rc = 1;

    if(o_key != key)
        block16_copy( o_key, key );
    copy_and_key( s1, in, o_key );

    for( r = 1 ; r < 10 ; ++r )
#if defined( VERSION_1 )
    {
        mix_sub_columns( s1 );
        update_encrypt_key_128( o_key, &rc );
        add_round_key( s1, o_key );
    }
#else
    {   uint_8t s2[N_BLOCK];
        mix_sub_columns( s2, s1 );
        update_encrypt_key_128( o_key, &rc );
        copy_and_key( s1, s2, o_key );
    }
#endif

    shift_sub_rows( s1 );
    update_encrypt_key_128( o_key, &rc );
    copy_and_key( out, s1, o_key );
}

#endif

#if defined( AES_DEC_128_OTFK )

/*  The 'on the fly' decryption key update for for 128 bit keys */

static void update_decrypt_key_128( uint_8t k[N_BLOCK], uint_8t *rc )
{   uint_8t cc;

    for( cc = 12; cc > 0; cc -= 4 )
    {
        k[cc + 0] ^= k[cc - 4];
        k[cc + 1] ^= k[cc - 3];
        k[cc + 2] ^= k[cc - 2];
        k[cc + 3] ^= k[cc - 1];
    }
    *rc = d2(*rc);
    k[0] ^= s_box[k[13]] ^ *rc;
    k[1] ^= s_box[k[14]];
    k[2] ^= s_box[k[15]];
    k[3] ^= s_box[k[12]];
}

/*  Decrypt a single block of 16 bytes with 'on the fly' 128 bit keying */

void aes_decrypt_128( const unsigned char in[N_BLOCK], unsigned char out[N_BLOCK],
                      const unsigned char key[N_BLOCK], unsigned char o_key[N_BLOCK] )
{
    uint_8t s1[N_BLOCK], r, rc = 0x6c;
    if(o_key != key)
        block16_copy( o_key, key );

    copy_and_key( s1, in, o_key );
    inv_shift_sub_rows( s1 );

    for( r = 10 ; --r ; )
#if defined( VERSION_1 )
    {
        update_decrypt_key_128( o_key, &rc );
        add_round_key( s1, o_key );
        inv_mix_sub_columns( s1 );
    }
#else
    {   uint_8t s2[N_BLOCK];
        update_decrypt_key_128( o_key, &rc );
        copy_and_key( s2, s1, o_key );
        inv_mix_sub_columns( s1, s2 );
    }
#endif
    update_decrypt_key_128( o_key, &rc );
    copy_and_key( out, s1, o_key );
}

#endif

#if defined( AES_ENC_256_OTFK )

/*  The 'on the fly' encryption key update for for 256 bit keys */

static void update_encrypt_key_256( uint_8t k[2 * N_BLOCK], uint_8t *rc )
{   uint_8t cc;

    k[0] ^= s_box[k[29]] ^ *rc;
    k[1] ^= s_box[k[30]];
    k[2] ^= s_box[k[31]];
    k[3] ^= s_box[k[28]];
    *rc = f2( *rc );

    for(cc = 4; cc < 16; cc += 4)
    {
        k[cc + 0] ^= k[cc - 4];
        k[cc + 1] ^= k[cc - 3];
        k[cc + 2] ^= k[cc - 2];
        k[cc + 3] ^= k[cc - 1];
    }

    k[16] ^= s_box[k[12]];
    k[17] ^= s_box[k[13]];
    k[18] ^= s_box[k[14]];
    k[19] ^= s_box[k[15]];

    for( cc = 20; cc < 32; cc += 4 )
    {
        k[cc + 0] ^= k[cc - 4];
        k[cc + 1] ^= k[cc - 3];
        k[cc + 2] ^= k[cc - 2];
        k[cc + 3] ^= k[cc - 1];
    }
}

/*  Encrypt a single block of 16 bytes with 'on the fly' 256 bit keying */

void aes_encrypt_256( const unsigned char in[N_BLOCK], unsigned char out[N_BLOCK],
                      const unsigned char key[2 * N_BLOCK], unsigned char o_key[2 * N_BLOCK] )
{
    uint_8t s1[N_BLOCK], r, rc = 1;
    if(o_key != key)
    {
        block16_copy( o_key, key );
        block16_copy( o_key + 16, key + 16 );
    }
    copy_and_key( s1, in, o_key );

    for( r = 1 ; r < 14 ; ++r )
#if defined( VERSION_1 )
    {
        mix_sub_columns(s1);
        if( r & 1 )
            add_round_key( s1, o_key + 16 );
        else
        {
            update_encrypt_key_256( o_key, &rc );
            add_round_key( s1, o_key );
        }
    }
#else
    {   uint_8t s2[N_BLOCK];
        mix_sub_columns( s2, s1 );
        if( r & 1 )
            copy_and_key( s1, s2, o_key + 16 );
        else
        {
            update_encrypt_key_256( o_key, &rc );
            copy_and_key( s1, s2, o_key );
        }
    }
#endif

    shift_sub_rows( s1 );
    update_encrypt_key_256( o_key, &rc );
    copy_and_key( out, s1, o_key );
}

#endif

#if defined( AES_DEC_256_OTFK )

/*  The 'on the fly' encryption key update for for 256 bit keys */

static void update_decrypt_key_256( uint_8t k[2 * N_BLOCK], uint_8t *rc )
{   uint_8t cc;

    for(cc = 28; cc > 16; cc -= 4)
    {
        k[cc + 0] ^= k[cc - 4];
        k[cc + 1] ^= k[cc - 3];
        k[cc + 2] ^= k[cc - 2];
        k[cc + 3] ^= k[cc - 1];
    }

    k[16] ^= s_box[k[12]];
    k[17] ^= s_box[k[13]];
    k[18] ^= s_box[k[14]];
    k[19] ^= s_box[k[15]];

    for(cc = 12; cc > 0; cc -= 4)
    {
        k[cc + 0] ^= k[cc - 4];
        k[cc + 1] ^= k[cc - 3];
        k[cc + 2] ^= k[cc - 2];
        k[cc + 3] ^= k[cc - 1];
    }

    *rc = d2(*rc);
    k[0] ^= s_box[k[29]] ^ *rc;
    k[1] ^= s_box[k[30]];
    k[2] ^= s_box[k[31]];
    k[3] ^= s_box[k[28]];
}

/*  Decrypt a single block of 16 bytes with 'on the fly'
    256 bit keying
*/
void aes_decrypt_256( const unsigned char in[N_BLOCK], unsigned char out[N_BLOCK],
                      const unsigned char key[2 * N_BLOCK], unsigned char o_key[2 * N_BLOCK] )
{
    uint_8t s1[N_BLOCK], r, rc = 0x80;

    if(o_key != key)
    {
        block16_copy( o_key, key );
        block16_copy( o_key + 16, key + 16 );
    }

    copy_and_key( s1, in, o_key );
    inv_shift_sub_rows( s1 );

    for( r = 14 ; --r ; )
#if defined( VERSION_1 )
    {
        if( ( r & 1 ) )
        {
            update_decrypt_key_256( o_key, &rc );
            add_round_key( s1, o_key + 16 );
        }
        else
            add_round_key( s1, o_key );
        inv_mix_sub_columns( s1 );
    }
#else
    {   uint_8t s2[N_BLOCK];
        if( ( r & 1 ) )
        {
            update_decrypt_key_256( o_key, &rc );
            copy_and_key( s2, s1, o_key + 16 );
        }
        else
            copy_and_key( s2, s1, o_key );
        inv_mix_sub_columns( s1, s2 );
    }
#endif
    copy_and_key( out, s1, o_key );
}

#endif