dse.c

这个极其小巧（9k）的加密程序对文件进行加密及解密的速度与资源管理器拷贝文件的速度一样快。因为速度快

/*=======================================================================
DSE v1.00-CLI (command-line interface)                    rev: 2004.09.17

Copyright (c) 2004 Dariusz Stanislawek
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:

1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
3. The name of the author may not be used to endorse or promote products
   derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
=========================================================================

DSE is a file encryption program.

Cipher: AES (Rijndael)
Mode: CFB-128
Key: 256 bits
IV: 16 bytes
Max File Size: unlimited
Cipher File Structure: [IV = 16 random bytes] + [cipherdata]

Change Log
----------
v1.00
- released 2004.09.17

Website
-------
http://www.ozemail.com.au/~nulifetv/freezip/freeware/
http://freezip.cjb.net/freeware/
                                                  freezip(at)bigfoot,com
=======================================================================*/


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
#include <conio.h> // for getch() and putch()
#include "rijndael-alg-fst.h"

#define KEY_SIZE 32 // bytes
#define IV_SIZE 16
#define IO_SIZE (64 * 1024) // the optimal buffer size for sequential I/O on Windows NT/2k/XP

//typedef unsigned char u8;
//typedef unsigned int u32;


void gen_iv(u8 *buf, int size)
{
    while(--size >= 0) buf[size] += rand();
}

char msg1[] = "%s: The data is invalid\n";
char msg2[] = "%s: The file exists\n";


/*=====================================================================*/


int crypt(char *keyfile, int encrypt, char *src, char *dst)
{
    int Nr; /* key-length-dependent number of rounds */
    u32 rk[4*(MAXNR + 1)]; /* key schedule */
    FILE *fkey, *fsrc, *fdst;
    u8 iv[IV_SIZE], cipherKey[KEY_SIZE], filebuf[IO_SIZE], block[16], *in, *out;
    int i, numBlocks, sread, status = 1, round = 0;

    if((fdst = fopen(dst, "r")) != NULL) // check if file exists
    {
        printf(msg2, dst);
        fclose(fdst);
        return 1;
    }

    if((fkey = fopen(keyfile, "rb")) == NULL)
    {
        perror(keyfile);
        return 1;
    }

    if((fsrc = fopen(src, "rb")) == NULL)
    {
        perror(src);
        goto quit;
    }

    if((fdst = fopen(dst, "wb")) == NULL)
    {
        perror(dst);
        goto quit;
    }


    if(KEY_SIZE != fread(cipherKey, 1, KEY_SIZE + 1, fkey))
    {
        printf(msg1, keyfile);
        goto quit;
    }


    if(encrypt)
    {
        strcpy(filebuf, src); // PRNG init 1
        for(i = (IO_SIZE / 4) - 1; i >= 0; i--) sread += ((int*)filebuf)[i]; // PRNG init 2
        srand(sread ^ time(NULL)); // PRNG init 3
        gen_iv(iv, IV_SIZE); // PRNG
        if(IV_SIZE != fwrite(iv, 1, IV_SIZE, fdst))
        {
            printf(msg1, dst);
            goto quit;
        }
    }
    else
    {
        if(IV_SIZE != fread(iv, 1, IV_SIZE, fsrc))
        {
            printf(msg1, src);
            goto quit;
        }
    }


    Nr = rijndaelKeySetupEnc(rk, cipherKey, KEY_SIZE * 8);


    while((sread = fread(filebuf, 1, IO_SIZE, fsrc)) > 0)
    {
        in = iv;
        out = filebuf;
        numBlocks = sread / 16;
        if(sread % 16) numBlocks++;
        for(i = numBlocks; i > 0; i--) // AES/CFB-128
        {
            rijndaelEncrypt(rk, Nr, in, block);
            if(!encrypt) memcpy(iv, out, 16);
            ((u32*)out)[0] ^= ((u32*)block)[0];
            ((u32*)out)[1] ^= ((u32*)block)[1];
            ((u32*)out)[2] ^= ((u32*)block)[2];
            ((u32*)out)[3] ^= ((u32*)block)[3];
            if(encrypt) in = out;
            out += 16;
        }
        if(encrypt) memcpy(iv, in, 16);
        if(sread != fwrite(filebuf, 1, sread, fdst))
        {
            printf(msg1, dst);
            goto quit;
        }
        round++;
        if(!(round % 16)) printf("."); // progress indicator
    }


    printf("DONE %uMB\n", round / 16);
    status = 0; // SUCCESS

quit:
    fclose(fkey);
    if(fsrc) fclose(fsrc);
    if(fdst)
    {
        fclose(fdst);
        if(status) remove(dst);
    }
    if(!encrypt) memset(filebuf, 0, sizeof(filebuf)); // sensitive data memory cleanup
    memset(cipherKey, 0, sizeof(cipherKey));
    rijndaelKeySetupEnc(rk, cipherKey, KEY_SIZE * 8);
    return status;
}


/*=====================================================================*/


int passgets(char *s, int n)
{
    int c;
    char *t;

    t = s;
    while(--n >= 0)
    {
        c = getch();
        if(c < 32 || c > 126) break;
        *s++ = c;
        putch('*');
    }
    *s = 0;
    return s != t;
}


int password(char *pass)
{
    char temp[33];

    memset(pass, 0, 32);
    printf("Password: ");
    if(passgets(pass, 32))
    {
        printf("\nVerify  : ");
        if(passgets(temp, 32) && !strcmp(pass, temp))
        {
            memset(temp, 0, 32);
            printf("\n");
            return 1;
        }
    }
    printf("\nError\n");
    return 0;
}


int gen_key(char *dst, int pass)
{
    int i, sum, Nr;
    u32 rk[4*(MAXNR + 1)];
    FILE *fdst;
    u8 block[512];

    if((fdst = fopen(dst, "r")) != NULL) // check if file exists
    {
        printf(msg2, dst);
        fclose(fdst);
        return 1;
    }

    if(pass)
    {
        if(!password(block)) return 1;
    }
    else strcpy(block, dst); // PRNG init 1

    if((fdst = fopen(dst, "wb")) == NULL)
    {
        perror(dst);
        return 1;
    }

    Nr = rijndaelKeySetupEnc(rk, block, 32 * 8);
    if(!pass)
    {
        for(i = (sizeof(block) / 4) - 1; i >= 0; i--) sum += ((int*)block)[i]; // PRNG init 2
        srand(sum ^ time(NULL)); // PRNG init 3
        gen_iv(block, 16); // PRNG
    }
    rijndaelEncrypt(rk, Nr, block, block + 16);
    rijndaelEncrypt(rk, Nr, block + 16, block);
    fwrite(block, 1, 32, fdst);
    fclose(fdst);
    printf("OK\n");
    memset(block, 0, 32);
    return 0;
}


/*=====================================================================*/


int main(int argc, char *argv[])
{
    if(argc == 2 || argc == 3) return gen_key(argv[1], argc == 3);
    if(argc == 5)
    {
        *argv[2] = toupper(*argv[2]);
        switch (*argv[2])
        {
        case 'E':
        case 'D':
            return crypt(argv[1], *argv[2] == 'E', argv[3], argv[4]);
        }
    }
    printf("DSE v1.00-CLI, Freeware - use at your own risk.\n"
           "(c)2004 Dariusz Stanislawek, http://freezip.cjb.net/freeware/\n\n"
           "Usage: dse keyfile e|d source destination\n\n"
           "Create a random-content key file: dse keyfile\n"
           "Create a key file from a password: dse keyfile p\n"
           "Key file size is 32 bytes.\n"
           "Encryption example: dse a:\\my.key e d:\\x\\data.zip data.enc\n"
           "Decryption example: dse my.key d data.enc c:\\tmp\\data.zip\n");
    return 1;
}