des.c

一个DES、3DES加解密的库文件

/* des.c */
/* Copyright (C) 1993 Eric Young - see README for more details */
#include <stdio.h>
#ifdef VMS
#include <types.h>
#include <stat.h>
#else
#ifndef _IRIX
#include <sys/types.h>
#endif
#include <sys/stat.h>
#endif
#include "des.h"

#if defined(__STDC__) || defined(VMS) || defined(M_XENIX) || defined(MSDOS)
#include <string.h>
#define bcopy(f,t,n)	memcpy(t,f,(size_t)(n))
#define bzero(s,n)	memset(s,0,(size_t)(n))
#define bcmp(a,b,n)	memcmp(a, b,(size_t)(n))
#define index(s,c)	strchr(s,c)
#endif

#ifdef PROTO
int usage(void);
int doencryption(void);
int uufwrite(char *data, int size, int num, FILE *fp);
int uufwriteEnd(FILE *fp);
int uufread(char *out,int size,int num,FILE *fp);
int uuencode(unsigned char *in,int num,unsigned char *out);
int uudecode(unsigned char *in,int num,unsigned char *out);
#else
int usage();
int doencryption();
int uufwrite();
int uufwriteEnd();
int uufread();
int uuencode();
int uudecode();
#endif

#ifdef VMS
#define EXIT(a) exit(a&0x10000000)
#else
#define EXIT(a) exit(a)
#endif

#define BUFSIZE (8*1024)
#define VERIFY  1
#define KEYSIZ	8
#define KEYSIZB 1024 /* should hit tty line limit first :-) */
char key[KEYSIZB+1];
int do_encrypt,longk=0;
char *in=NULL,*out=NULL;
FILE *DES_IN,*DES_OUT,*CKSUM_OUT;
char uuname[200];
char uubuf[50];
int uubufnum;
#define INUUBUFN	(45*100)
#define OUTUUBUF	(65*100)
char b[OUTUUBUF];
char bb[300];
des_cblock cksum={0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
char cksumname[200]="";

int cflag,eflag,dflag,kflag,bflag,fflag,sflag,uflag,flag3,hflag,error;

main(argc,argv)
int argc;
char *argv[];
	{
	int i;
	struct stat ins,outs;
	char *p;

	cflag=eflag=dflag=kflag=hflag=bflag=fflag=sflag=uflag=flag3=0,error=0;
	bzero(key,sizeof(key));

	for (i=1; i<argc; i++)
		{
		p=argv[i];
		if ((p[0] == '-') && (p[1] != '\0'))
			{
			p++;
			while (*p)
				{
				switch (*(p++))
					{
				case '3':
					flag3=1;
				/*	bflag=0; */
					longk=1;
					break;
				case 'c':
					cflag=1;
					strncpy(cksumname,p,200);
					p+=strlen(cksumname);
					break;
				case 'C':
					cflag=1;
					longk=1;
					strncpy(cksumname,p,200);
					p+=strlen(cksumname);
					break;
				case 'e':
					eflag=1;
					break;
				case 'E':
					eflag=1;
					longk=1;
					break;
				case 'd':
					dflag=1;
					break;
				case 'D':
					dflag=1;
					longk=1;
					break;
				case 'b':
					bflag=1;
					flag3=0;
					break;
				case 'f':
					fflag=1;
					break;
				case 's':
					sflag=1;
					break;
				case 'u':
					uflag=1;
					strncpy(uuname,p,200);
					p+=strlen(uuname);
					break;
				case 'h':
					hflag=1;
					break;
				case 'k':
					kflag=1;
					if ((i+1) == argc)
						{
						fputs("must have a key with the -k option\n",stderr);
						error=1;
						}
					else
						{
						int j;

						i++;
						strncpy(key,argv[i],KEYSIZB);
						for (j=strlen(argv[i])-1; j>=0; j--)
							argv[i][j]='\0';
						}
					break;
				default:
					fprintf(stderr,"'%c' unknown flag\n",p[-1]);
					error=1;
					break;
					}
				}
			}
		else
			{
			if (in == NULL)
				in=argv[i];
			else if (out == NULL)
				out=argv[i];
			else
				error=1;
			}
		}
	if (error) usage();
	/* We either
	 * do checksum or
	 * do encrypt or
	 * do decrypt or
	 * do decrypt then ckecksum or
	 * do checksum then encrypt
	 */
	if (((eflag+dflag) == 1) || cflag)
		{
		if (eflag) do_encrypt=DES_ENCRYPT;
		if (dflag) do_encrypt=DES_DECRYPT;
		}
	else
		usage();

	if (	(in != NULL) &&
		(out != NULL) &&
#ifndef MSDOS
		(stat(in,&ins) != -1) &&
		(stat(out,&outs) != -1) &&
		(ins.st_dev == outs.st_dev) &&
		(ins.st_ino == outs.st_ino))
#else /* MSDOS */
		(strcmp(in,out) == 0))
#endif
			{
			fputs("input and output file are the same\n",stderr);
			EXIT(3);
			}

	if (!kflag)
		if (des_read_pw_string(key,KEYSIZB+1,"Enter key:",eflag?VERIFY:0))
			{
			fputs("password error\n",stderr);
			EXIT(2);
			}

	if (in == NULL)
		DES_IN=stdin;
	else if ((DES_IN=fopen(in,"r")) == NULL)
		{
		perror("opening input file");
		EXIT(4);
		}

	CKSUM_OUT=stdout;
	if (out == NULL)
		{
		DES_OUT=stdout;
		CKSUM_OUT=stderr;
		}
	else if ((DES_OUT=fopen(out,"w")) == NULL)
		{
		perror("opening output file");
		EXIT(5);
		}

#ifdef MSDOS
	/* This should set the file to binary mode. */
	{
#include <fcntl.h>
	if (!(uflag && dflag))
		setmode(fileno(DES_IN),O_BINARY);
	if (!(uflag && eflag))
		setmode(fileno(DES_OUT),O_BINARY);
	}
#endif

	doencryption();
	fclose(DES_IN);
	fclose(DES_OUT);
	EXIT(0);
	}

usage()
	{
	char **u;
	static char *usage[]={
"des <options> [input-file [output-file]]",
"options:",
"-e         : encrypt using sunOS compatible user key to DES key conversion.",
"-E         : encrypt ",
"-d         : decrypt using sunOS compatible user key to DES key conversion.",
"-D         : decrypt ",
"-c[ckname] : generate a cbc_cksum using sunOS compatible user key to",
"             DES key conversion and output to ckname (stdout default,",
"             stderr if data being output on stdout).  The checksum is",
"             generated before encryption and after decryption if used",
"             in conjunction with -[eEdD].",
"-C[ckname] : generate a cbc_cksum as for -c but compatible with -[ED].",
"-k key     : use key 'key'",
"-h         : the key that is entered will be a hexidecimal number",
"-u[uuname] : input file is uudecoded if -[dD] or output uuencoded",
"             data if -[eE] (uuname is the filename to put in the",
"             uuencode header).",
"-b         : encrypt using DES in ecb encryption mode, the defaut is",
"             cbc mode.",
"-3         : encrypt using tripple DES encryption.  This uses 2 keys",
"             generated from the input key.  If the input key is less",
"             than 8 characters long, this is equivelent to normal",
"             encryption.  Default is tripple cbc, -b makes it tripple ecb.",
NULL
};
	for (u=usage; *u; u++)
		{
		fputs(*u,stderr);
		fputc('\n',stderr);
		}

	EXIT(1);
	}

doencryption()
	{
	register int i;
	des_key_schedule ks,ks2;
	unsigned char iv[8],iv2[8],iv3[8];
	char *p;
	int num=0,j,k,l,rem,ll,len,last,ex=0;
	des_cblock kk,k2;
	FILE *O;
	int Exit=0;
#ifndef MSDOS
	static unsigned char buf[BUFSIZE+8],obuf[BUFSIZE+8];
#else
	static unsigned char *buf=NULL,*obuf=NULL;

	if (buf == NULL)
		{
		if (    (( buf=(unsigned char *)malloc(BUFSIZE+8)) == NULL) ||
			((obuf=(unsigned char *)malloc(BUFSIZE+8)) == NULL))
			{
			fputs("Not enough memory\n",stderr);
			Exit=10;
			goto problems;
			}
		}
#endif

	if (hflag)
		{
		j=(flag3?16:8);
		p=key;
		for (i=0; i<j; i++)
			{
			k=0;
			if ((*p <= '9') && (*p >= '0'))
				k=(*p-'0')<<4;
			else if ((*p <= 'f') && (*p >= 'a'))
				k=(*p-'a'+10)<<4;
			else if ((*p <= 'F') && (*p >= 'A'))
				k=(*p-'A'+10)<<4;
			else
				{
				fputs("Bad hex key\n",stderr);
				Exit=9;
				goto problems;
				}
			p++;
			if ((*p <= '9') && (*p >= '0'))
				k|=(*p-'0');
			else if ((*p <= 'f') && (*p >= 'a'))
				k|=(*p-'a'+10);
			else if ((*p <= 'F') && (*p >= 'A'))
				k|=(*p-'A'+10);
			else
				{
				fputs("Bad hex key\n",stderr);
				Exit=9;
				goto problems;
				}
			p++;
			if (i < 8)
				kk[i]=k;
			else
				k2[i-8]=k;
			}
		des_set_key((C_Block *)k2,ks2);
		bzero(k2,sizeof(k2));
		}
	else if (longk || flag3)
		{
		if (flag3)
			{
			des_string_to_2keys(key,(C_Block *)kk,(C_Block *)k2);
			des_set_key((C_Block *)k2,ks2);
			bzero(k2,sizeof(k2));
			}
		else
			des_string_to_key(key,(C_Block *)kk);
		}
	else
		for (i=0; i<KEYSIZ; i++)
			{
			l=0;
			k=key[i];
			for (j=0; j<8; j++)
				{
				if (k&1) l++;
				k>>=1;
				}
			if (l & 1)
				kk[i]=key[i]&0x7f;
			else
				kk[i]=key[i]|0x80;
			}

	des_set_key((C_Block *)kk,ks);
	bzero(key,sizeof(key));
	bzero(kk,sizeof(kk));
	/* woops - A bug that does not showup under unix :-( */
	bzero(iv,sizeof(iv));
	bzero(iv2,sizeof(iv2));
	bzero(iv3,sizeof(iv3));

	l=1;
	rem=0;
	/* first read */
	if (eflag || (!dflag && cflag))
		{
		for (;;)
			{
			num=l=fread(&(buf[rem]),1,BUFSIZE,DES_IN);
			l+=rem;
			num+=rem;
			if (l < 0)
				{
				perror("read error");
				Exit=6;
				goto problems;
				}

			rem=l%8;
			len=l-rem;
			if (feof(DES_IN))
				{
				srand(time(NULL));
				for (i=7-rem; i>0; i--)
					buf[l++]=rand()&0xff;
				buf[l++]=rem;
				ex=1;
				len+=rem;
				}
			else
				l-=rem;

			if (cflag)
				{
				des_cbc_cksum((C_Block *)buf,(C_Block *)cksum,
					(long)len,ks,(C_Block *)cksum);
				if (!eflag)
					{
					if (feof(DES_IN)) break;
					else continue;
					}
				}

			if (bflag && !flag3)
				for (i=0; i<l; i+=8)
					des_ecb_encrypt(
						(des_cblock *)&(buf[i]),
						(des_cblock *)&(obuf[i]),
						ks,do_encrypt);