Pure golfed MD5

[mtve]

Here is obfuscated pure MD5, ready to put in .megasig :)

Input is on stdin, output is hexadecimal hash. Rules for this golf round are: code must be /^[\t\n -~]$/, input length < 2**32.

It's just a fuse for your ideas, because it will be massively squeezed after someone recalls generative polynomial for MD5 constants. Meanwhile feel free to shave strokes here and there.

#!perl -lp0777
BEGIN{$^H++}@Y=@R[-4..-1]if@R=unpack V68,unpack u,uc q{`
M>*1juu:wq^c;<"`D[lz]P:\/?/4jQh='$t8Pj`&51Ow8f(!ik_=$b[%;__^^
Muur)(A&0:Y-qf/v.0wff(0Bt26(E'O9`lt#`45i>)JK'MnE=$"_64q1$`H'F
MH=C(^]/GylWa(=8'-\.'#=7T[11:107IXZGxh^_\v0)O9xI,*Hu".?k_@?9q
mar)Ag6t,..7]1.j^i*g/wDm@2[Ov<+r_ol9^FRCz)Z'JA3#ou`4=B`0yt-39
My9g;yoA\ha]e5js$1"(i])?_*d.g(y2k.:"3_,-96V62S`r/??3o_]%=A(5/
m?JaoX.8l_a1#`:.a$0a.@gy3]s7r.kv[tm<jd=.&zp$c16>)j\wo_mRzf'94
",a};$_.=v128;//;for(/\C{57,64}/g,pack a56V,$',8*y///c-8){@V=
unpack V16,$_.v0 x8;@_=@Y;for$K(0..3){$I=(0,1,5)[$K];($D,$A,$
B,$C)=@_[-$_|-4..2],$_[-$_&3]=(($D+=($A&$B|~$A&$C,$A&$C|$B&~$
C,$A^$B^$C,$B^($A|~$C))[$K]+$V[$I&15]+$R[$K*16+$_])<<($N=ord(
(GlqvEIn4DkPWfjOU=~/./g)[$K*4+$_%4])%32)|2**$N-1&$D>>32-$N)+$
A,$I+=(1,5,3,7)[$K]for 0..15}map$_+=shift@_,@Y}$_=unpack H64,
pack V4,@Y

[mtve]

Duh, v128 plays very bad joke on v5.8.0. Fixed and improved version follows (418):

#!perl -lp0777
sub n{unpack$_[0],pop}sub f{"@_"%2**32}@Y=n V4,n u,'0`2-%9XFKS>_^W+J8=
+E0R$';$_
.=pack Bx.(55- y///c&63).VV,1,8*y///c;s!\C{64}!@V=n V16,$&;@:=@Y;$_='f
+orK(0..3)
{(C,D,A,B)=@:=@:[-1..2],$:[1]=fA+((D=fD+(A&B|~A&C,A&C|B&~C,A^B^C,A|~C^
+B)[K]+V[K
**2.4%13+(1+K+K%2*3)*_&15]+int 2**32*abs sinK*16+_+1)<<(N=31&n x.(K*4+
+_%4).c,
glqvein4dkpwfjou)|D>>32-N)for 0..15}_=f_+shift@:for@Y';s/[A-V_]/\$$&/g
+;$_!eeg;$
_=n H64,pack V4,@Y

P.S. April 14th. Legacy support costs too much, i decided to drop it. v5.8.0 only version is 403 and fits into five lines:

#!perl -lp0777
sub n{unpack$_[0],pop}sub f{"@_"%2**32}@Y=n V4,n u,'0`2-%9XFKS>_^W+J8=
+E0R$';$_=
pack'a*Bx8x!64X8VV',$_,1,8*y///c;s!\C{64}!$_='forK(0..3){(C,D,A,B)=@:=
+@:[-1..2]
,$:[1]=fA+((D=fD+(A&B|~A&C,A&C|B&~C,A^B^C,A|~C^B)[K]+V[K**2.55+(1+K+K%
+2*3)*_&15
]+2**32*abs sin++$@)<<(N=31&n x.(K*4+_%4).c,glqvein4dkpwfjou)|D>>32-N)
+forE..15}
_=f_+shift@:for@Y';@V=n V16,$&;@:=@Y;s/[A-V_]/\$$&/g;$_!eeg;$_=n H64,p
+ack V4,@Y