des.c

本软件是根据DES加密算法

		{
		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))
				{
				srandom((unsigned int)time(NULL));
				for (i=7-rem; i>0; i--)
					buf[l++]=random()&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);
			else if (flag3 && bflag)
				for (i=0; i<l; i+=8)
					des_ecb2_encrypt(
						(des_cblock *)&(buf[i]),
						(des_cblock *)&(obuf[i]),
						ks,ks2,do_encrypt);
			else if (flag3 && !bflag)
				{
				char tmpbuf[8];

				if (rem) memcpy(tmpbuf,&(buf[l]),
					(unsigned int)rem);
				des_3cbc_encrypt(
					(des_cblock *)buf,(des_cblock *)obuf,
					(long)l,ks,ks2,(des_cblock *)iv,
					(des_cblock *)iv2,do_encrypt);
				if (rem) memcpy(&(buf[l]),tmpbuf,
					(unsigned int)rem);
				}
			else
				{
				des_cbc_encrypt(
					(des_cblock *)buf,(des_cblock *)obuf,
					(long)l,ks,(des_cblock *)iv,do_encrypt);
				if (l >= 8) memcpy(iv,&(obuf[l-8]),8);
				}
			if (rem) memcpy(buf,&(buf[l]),(unsigned int)rem);

			i=0;
			while (i < l)
				{
				if (uflag)
					j=uufwrite(obuf,1,(unsigned int)l-i,
						DES_OUT);
				else
					j=fwrite(obuf,1,(unsigned int)l-i,
						DES_OUT);
				if (j == -1)
					{
					perror("Write error");
					Exit=7;
					goto problems;
					}
				i+=j;
				}
			if (feof(DES_IN))
				{
				if (uflag) uufwriteEnd(DES_OUT);
				break;
				}
			}
		}
	else /* decrypt */
		{
		ex=1;
		for (;;)
			{
			if (ex) {
				if (uflag)
					l=uufread(buf,1,BUFSIZE,DES_IN);
				else
					l=fread(buf,1,BUFSIZE,DES_IN);
				ex=0;
				rem=l%8;
				l-=rem;
				}
			if (l < 0)
				{
				perror("read error");
				Exit=6;
				goto problems;
				}

			if (bflag && !flag3)
				for (i=0; i<l; i+=8)
					des_ecb_encrypt(
						(des_cblock *)&(buf[i]),
						(des_cblock *)&(obuf[i]),
						ks,do_encrypt);
			else if (flag3 && bflag)
				for (i=0; i<l; i+=8)
					des_ecb2_encrypt(
						(des_cblock *)&(buf[i]),
						(des_cblock *)&(obuf[i]),
						ks,ks2,do_encrypt);
			else if (flag3 && !bflag)
				{
				des_3cbc_encrypt(
					(des_cblock *)buf,(des_cblock *)obuf,
					(long)l,ks,ks2,(des_cblock *)iv,
					(des_cblock *)iv2,do_encrypt);
				}
			else
				{
				des_cbc_encrypt(
					(des_cblock *)buf,(des_cblock *)obuf,
				 	(long)l,ks,(des_cblock *)iv,do_encrypt);
				if (l >= 8) memcpy(iv,&(buf[l-8]),8);
				}

			if (uflag)
				ll=uufread(&(buf[rem]),1,BUFSIZE,DES_IN);
			else
				ll=fread(&(buf[rem]),1,BUFSIZE,DES_IN);
			ll+=rem;
			rem=ll%8;
			ll-=rem;
			if (feof(DES_IN) && (ll == 0))
				{
				last=obuf[l-1];

				if ((last > 7) || (last < 0))
					{
					fputs("The file was not decrypted correctly.\n",
						stderr);
					Exit=8;
					last=0;
					}
				l=l-8+last;
				}
			i=0;
			if (cflag) des_cbc_cksum((C_Block *)obuf,
				(C_Block *)cksum,(long)l/8*8,ks,
				(C_Block *)cksum);
			while (i != l)
				{
				j=fwrite(obuf,1,(unsigned int)l-i,DES_OUT);
				if (j == -1)
					{
					perror("Write error");
					Exit=7;
					goto problems;
					}
				i+=j;
				}
			l=ll;
			if ((l == 0) && feof(DES_IN)) break;
			}
		}
	if (cflag)
		{
		l=0;
		if (cksumname[0] != '\0')
			{
			if ((O=fopen(cksumname,"w")) != NULL)
				{
				CKSUM_OUT=O;
				l=1;
				}
			}
		for (i=0; i<8; i++)
			fprintf(CKSUM_OUT,"%02X",cksum[i]);
		fprintf(CKSUM_OUT,"\n");
		if (l) fclose(CKSUM_OUT);
		}
problems:
	memset(buf,0,sizeof(buf));
	memset(obuf,0,sizeof(obuf));
	memset(ks,0,sizeof(ks));
	memset(ks2,0,sizeof(ks2));
	memset(iv,0,sizeof(iv));
	memset(iv2,0,sizeof(iv2));
	memset(kk,0,sizeof(kk));
	memset(k2,0,sizeof(k2));
	memset(uubuf,0,sizeof(uubuf));
	memset(b,0,sizeof(b));
	memset(bb,0,sizeof(bb));
	memset(cksum,0,sizeof(cksum));
	if (Exit) EXIT(Exit);
	}

int uufwrite(data, size, num, fp)
unsigned char *data;
int size;
unsigned int num;
FILE *fp;
      
     /* We ignore this parameter but it should be > ~50 I believe */
   
    
	{
	int i,j,left,rem,ret=num;
	static int start=1;

	if (start)
		{
		fprintf(fp,"begin 600 %s\n",
			(uuname[0] == '\0')?"text.d":uuname);
		start=0;
		}

	if (uubufnum)
		{
		if (uubufnum+num < 45)
			{
			memcpy(&(uubuf[uubufnum]),data,(unsigned int)num);
			uubufnum+=num;
			return(num);
			}
		else
			{
			i=45-uubufnum;
			memcpy(&(uubuf[uubufnum]),data,(unsigned int)i);
			j=uuencode((unsigned char *)uubuf,45,b);
			fwrite(b,1,(unsigned int)j,fp);
			uubufnum=0;
			data+=i;
			num-=i;
			}
		}

	for (i=0; i<(((int)num)-INUUBUFN); i+=INUUBUFN)
		{
		j=uuencode(&(data[i]),INUUBUFN,b);
		fwrite(b,1,(unsigned int)j,fp);
		}
	rem=(num-i)%45;
	left=(num-i-rem);
	if (left)
		{
		j=uuencode(&(data[i]),left,b);
		fwrite(b,1,(unsigned int)j,fp);
		i+=left;
		}
	if (i != num)
		{
		memcpy(uubuf,&(data[i]),(unsigned int)rem);
		uubufnum=rem;
		}
	return(ret);
	}

void uufwriteEnd(fp)
FILE *fp;
	{
	int j;
	static const char *end=" \nend\n";

	if (uubufnum != 0)
		{
		uubuf[uubufnum]='\0';
		uubuf[uubufnum+1]='\0';
		uubuf[uubufnum+2]='\0';
		j=uuencode(uubuf,uubufnum,b);
		fwrite(b,1,(unsigned int)j,fp);
		}
	fwrite(end,1,strlen(end),fp);
	}

int uufread(out, size, num, fp)
unsigned char *out;
int size; /* should always be > ~ 60; I actually ignore this parameter :-) */
unsigned int num;
FILE *fp;
	{
	int i,j,tot;
	static int done=0;
	static int valid=0;
	static int start=1;

	if (start)
		{
		for (;;)
			{
			b[0]='\0';
			fgets((char *)b,300,fp);
			if (b[0] == '\0')
				{
				fprintf(stderr,"no 'begin' found in uuencoded input\n");
				return(-1);
				}
			if (strncmp((char *)b,"begin ",6) == 0) break;
			}
		start=0;
		}
	if (done) return(0);
	tot=0;
	if (valid)
		{
		memcpy(out,bb,(unsigned int)valid);
		tot=valid;
		valid=0;
		}
	for (;;)
		{
		b[0]='\0';
		fgets((char *)b,300,fp);
		if (b[0] == '\0') break;
		i=strlen((char *)b);
		if ((b[0] == 'e') && (b[1] == 'n') && (b[2] == 'd'))
			{
			done=1;
			while (!feof(fp))
				{
				fgets((char *)b,300,fp);
				}
			break;
			}
		i=uudecode(b,i,bb);
		if (i < 0) break;
		if ((i+tot+8) > num)
			{
			/* num to copy to make it a multiple of 8 */
			j=(num/8*8)-tot-8;
			memcpy(&(out[tot]),bb,(unsigned int)j);
			tot+=j;
			memcpy(bb,&(bb[j]),(unsigned int)i-j);
			valid=i-j;
			break;
			}
		memcpy(&(out[tot]),bb,(unsigned int)i);
		tot+=i;
		}
	return(tot);
	}

#define ccc2l(c,l)      (l =((DES_LONG)(*((c)++)))<<16, \
			 l|=((DES_LONG)(*((c)++)))<< 8, \
		 	 l|=((DES_LONG)(*((c)++))))

#define l2ccc(l,c)      (*((c)++)=(unsigned char)(((l)>>16)&0xff), \
                    *((c)++)=(unsigned char)(((l)>> 8)&0xff), \
                    *((c)++)=(unsigned char)(((l)    )&0xff))


int uuencode(in, num, out)
unsigned char *in;
int num;
unsigned char *out;
	{
	int j,i,n,tot=0;
	DES_LONG l;
	register unsigned char *p;
	p=out;

	for (j=0; j<num; j+=45)
		{
		if (j+45 > num)
			i=(num-j);
		else	i=45;
		*(p++)=i+' ';
		for (n=0; n<i; n+=3)
			{
			ccc2l(in,l);
			*(p++)=((l>>18)&0x3f)+' ';
			*(p++)=((l>>12)&0x3f)+' ';
			*(p++)=((l>> 6)&0x3f)+' ';
			*(p++)=((l    )&0x3f)+' ';
			tot+=4;
			}
		*(p++)='\n';
		tot+=2;
		}
	*p='\0';
	l=0;
	return(tot);
	}

int uudecode(in, num, out)
unsigned char *in;
int num;
unsigned char *out;
	{
	int j,i,k;
	unsigned int n=0,space=0;
	DES_LONG l;
	DES_LONG w,x,y,z;
	unsigned int blank=(unsigned int)'\n'-' ';

	for (j=0; j<num; )
		{
		n= *(in++)-' ';
		if (n == blank)
			{
			n=0;
			in--;
			}
		if (n > 60)
			{
			fprintf(stderr,"uuencoded line length too long\n");
			return(-1);
			}
		j++;

		for (i=0; i<n; j+=4,i+=3)
			{
			/* the following is for cases where spaces are
			 * removed from lines.
			 */
			if (space)
				{
				w=x=y=z=0;
				}
			else
				{
				w= *(in++)-' ';
				x= *(in++)-' ';
				y= *(in++)-' ';
				z= *(in++)-' ';
				}
			if ((w > 63) || (x > 63) || (y > 63) || (z > 63))
				{
				k=0;
				if (w == blank) k=1;
				if (x == blank) k=2;
				if (y == blank) k=3;
				if (z == blank) k=4;
				space=1;
				switch (k) {
				case 1:	w=0; in--;
				case 2: x=0; in--;
				case 3: y=0; in--;
				case 4: z=0; in--;
					break;
				case 0:
					space=0;
					fprintf(stderr,"bad uuencoded data values\n");
					w=x=y=z=0;
					return(-1);
					break;
					}
				}
			l=(w<<18)|(x<<12)|(y<< 6)|(z    );
			l2ccc(l,out);
			}
		if (*(in++) != '\n')
			{
			fprintf(stderr,"missing nl in uuencoded line\n");
			w=x=y=z=0;
			return(-1);
			}
		j++;
		}
	*out='\0';
	w=x=y=z=0;
	return(n);
	}