md5碰撞原理分析

sha碰撞,MD5碰撞实现，#!/usr/local/bin/perl # It was noted that Intel IA-32 C compiler generates code which # performs ~30% *faster* on P4 CPU than original *hand-coded* # SHA1 assembler implementation. To address this problem (and # prove that humans are still better than machines:-), the # original code was overhauled, which resulted in following # performance changes: # # compared with original compared with Intel cc # assembler impl. generated code # Pentium -25% +37% # PIII/AMD +8% +16% # P4 +85%(!) +45% # # As you can see Pentium came out as looser:-( Yet I reckoned that # improvement on P4 outweights the loss and incorporate this # re-tuned code to 0.9.7 and later. # ---------------------------------------------------------------- # Those who for any particular reason absolutely must score on # Pentium can replace this module with one from 0.9.6 distribution. # This "offer" shall be revoked the moment programming interface to # this module is changed, in which case this paragraph should be # removed. # ---------------------------------------------------------------- # <appro@fy.chalmers.se> $normal=0; push(@INC,"perlasm","../../perlasm"); require "x86asm.pl"; &asm_init($ARGV[0],"sha1-586.pl",$ARGV[$#ARGV] eq "386"); $A="eax"; $B="ecx"; $C="ebx"; $D="edx"; $E="edi"; $T="esi"; $tmp1="ebp"; $off=9*4; @K=(0x5a827999,0x6ed9eba1,0x8f1bbcdc,0xca62c1d6); &sha1_block_data("sha1_block_asm_data_order"); &asm_finish(); sub Nn { local($p)=@_; local(%n)=($A,$T,$B,$A,$C,$B,$D,$C,$E,$D,$T,$E); return($n{$p}); } sub Np { local($p)=@_; local(%n)=($A,$T,$B,$A,$C,$B,$D,$C,$E,$D,$T,$E); local(%n)=($A,$B,$B,$C,$C,$D,$D,$E,$E,$T,$T,$A); return($n{$p}); } sub Na { local($n)=@_; return( (($n )&0x0f), (($n+ 2)&0x0f), (($n+ 8)&0x0f), (($n+13)&0x0f), (($n+ 1)&0x0f)); } sub X_expand { local($in)=@_; &comment("First, load the words onto the stack in network byte order"); for ($i=0; $i<16; $i+=2) { &mov($A,&DWP(($i+0)*4,$in,"",0));# unless $i == 0; &mov($B,&DWP(($i+1)*4,$in,"