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Diffstat (limited to 'eBones/des/qud_cksm.c')
| -rw-r--r-- | eBones/des/qud_cksm.c | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/eBones/des/qud_cksm.c b/eBones/des/qud_cksm.c new file mode 100644 index 0000000..eb7773f --- /dev/null +++ b/eBones/des/qud_cksm.c @@ -0,0 +1,93 @@ +/* qud_cksm.c */ +/* Copyright (C) 1993 Eric Young - see README for more details */ + +/*- + * $Id: qud_cksm.c,v 1.2 1994/07/19 19:22:02 g89r4222 Exp $ + */ + +/* From "Message Authentication" R.R. Jueneman, S.M. Matyas, C.H. Meyer + * IEEE Communications Magazine Sept 1985 Vol. 23 No. 9 p 29-40 + * This module in only based on the code in this paper and is + * almost definitely not the same as the MIT implementation. + */ +#include "des_locl.h" + +/* bug fix for dos - 7/6/91 - Larry hughes@logos.ucs.indiana.edu */ +#define B0(a) (((unsigned long)(a))) +#define B1(a) (((unsigned long)(a))<<8) +#define B2(a) (((unsigned long)(a))<<16) +#define B3(a) (((unsigned long)(a))<<24) + +/* used to scramble things a bit */ +/* Got the value MIT uses via brute force :-) 2/10/90 eay */ +#define NOISE ((unsigned long)83653421) + +unsigned long des_quad_cksum(input,output,length,out_count,seed) +des_cblock *input; +des_cblock *output; +long length; +int out_count; +des_cblock *seed; + { + unsigned long z0,z1,t0,t1; + int i; + long l=0; + unsigned char *cp; + unsigned char *lp; + + if (out_count < 1) out_count=1; + lp=(unsigned char *)output; + + z0=B0((*seed)[0])|B1((*seed)[1])|B2((*seed)[2])|B3((*seed)[3]); + z1=B0((*seed)[4])|B1((*seed)[5])|B2((*seed)[6])|B3((*seed)[7]); + + for (i=0; ((i<4)&&(i<out_count)); i++) + { + cp=(unsigned char *)input; + l=length; + while (l > 0) + { + if (l > 1) + { + t0= (unsigned long)(*(cp++)); + t0|=(unsigned long)B1(*(cp++)); + l--; + } + else + t0= (unsigned long)(*(cp++)); + l--; + /* add */ + t0+=z0; + t0&=0xffffffff; + t1=z1; + /* square, well sort of square */ + z0=((((t0*t0)&0xffffffff)+((t1*t1)&0xffffffff)) + &0xffffffff)%0x7fffffff; + z1=((t0*((t1+NOISE)&0xffffffff))&0xffffffff)%0x7fffffff; + } + if (lp != NULL) + { + /* I believe I finally have things worked out. + * The MIT library assumes that the checksum + * is one huge number and it is returned in a + * host dependant byte order. + */ + static unsigned long l=1; + static unsigned char *c=(unsigned char *)&l; + + if (c[0]) + { + l2c(z0,lp); + l2c(z1,lp); + } + else + { + lp=output[out_count-i-1]; + l2n(z1,lp); + l2n(z0,lp); + } + } + } + return(z0); + } + |
