diff options
Diffstat (limited to 'eBones/des/ofb_enc.c')
| -rw-r--r-- | eBones/des/ofb_enc.c | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/eBones/des/ofb_enc.c b/eBones/des/ofb_enc.c new file mode 100644 index 0000000..9a94372 --- /dev/null +++ b/eBones/des/ofb_enc.c @@ -0,0 +1,72 @@ +/* ofb_enc.c */ +/* Copyright (C) 1993 Eric Young - see README for more details */ + +/*- + * $Id: ofb_enc.c,v 1.2 1994/07/19 19:21:59 g89r4222 Exp $ + */ + +#include "des_locl.h" + +/* The input and output are loaded in multiples of 8 bits. + * What this means is that if you hame numbits=12 and length=2 + * the first 12 bits will be retrieved from the first byte and half + * the second. The second 12 bits will come from the 3rd and half the 4th + * byte. + */ +int des_ofb_encrypt(in,out,numbits,length,schedule,ivec) +unsigned char *in,*out; +int numbits; +long length; +des_key_schedule schedule; +des_cblock *ivec; + { + register unsigned long d0,d1,v0,v1,n=(numbits+7)/8; + register unsigned long mask0,mask1; + register long l=length; + register int num=numbits; + unsigned long ti[2]; + unsigned char *iv; + + if (num > 64) return(0); + if (num > 32) + { + mask0=0xffffffff; + if (num >= 64) + mask1=mask0; + else + mask1=(1L<<(num-32))-1; + } + else + { + if (num == 32) + mask0=0xffffffff; + else + mask0=(1L<<num)-1; + mask1=0x00000000; + } + + iv=(unsigned char *)ivec; + c2l(iv,v0); + c2l(iv,v1); + ti[0]=v0; + ti[1]=v1; + while (l-- > 0) + { + des_encrypt((unsigned long *)ti,(unsigned long *)ti, + schedule,DES_ENCRYPT); + c2ln(in,d0,d1,n); + in+=n; + d0=(d0^ti[0])&mask0; + d1=(d1^ti[1])&mask1; + l2cn(d0,d1,out,n); + out+=n; + } + v0=ti[0]; + v1=ti[1]; + iv=(unsigned char *)ivec; + l2c(v0,iv); + l2c(v1,iv); + v0=v1=d0=d1=ti[0]=ti[1]=0; + return(0); + } + |
