crypto (2).ahk

hashPassword(username,pwd){
	global k0,k1,k2,k3, l0,l1, m0,m1
	pwString := username pwd
	Return %  XCBC(Hex(pwString,StrLen(pwString)), 0,0, k0,k1,k2,k3, l0,l1, m0,m1)
}


; http://www.autohotkey.com/community/viewtopic.php?f=2&t=5763

; for my needs, the key doesn't need to be secret. (we aren't registering a program here)

k0 = 0x11111111                  ; 128-bit secret key (example)
k1 = 0x22222222
k2 = 0x33333333
k3 = 0x44444444

l0 = 0x12345678                  ; 64- bit 2nd secret key (example)
l1 = 0x12345678

m0 = 0x87654321                  ; 64- bit 3rd secret key (example)
m1 = 0x87654321

;---- Crypto functions ----;

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; TEA cipher ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Block encryption with the TEA cipher
; [y,z] = 64-bit I/0 block
; [k0,k1,k2,k3] = 128-bit key
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

TEA(ByRef y,ByRef z, k0,k1,k2,k3)
{                                   ; need  SetFormat Integer, D
   s = 0
   d = 0x9E3779B9
   Loop 32                          ; could be reduced to 8 for speed
   {
      k := "k" . s & 3              ; indexing the key
      y := 0xFFFFFFFF & (y + ((z << 4 ^ z >> 5) + z  ^  s + %k%))
      s := 0xFFFFFFFF & (s + d)  ; simulate 32 bit operations
      k := "k" . s >> 11 & 3
      z := 0xFFFFFFFF & (z + ((y << 4 ^ y >> 5) + y  ^  s + %k%))
   }
}

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; XCBC-MAC ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; x  = long hex string input
; [u,v] = 64-bit initial value (0,0)
; [k0,k1,k2,k3] = 128-bit key
; [l0,l1] = 64-bit key for not padded last block
; [m0,m1] = 64-bit key for padded last block
; Return 16 hex digits (64 bits) digest
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

XCBC(x, u,v, k0,k1,k2,k3, l0,l1, m0,m1)
{
   Loop % Ceil(StrLen(x)/16)-1   ; full length intermediate message blocks
      XCBCstep(u, v, x, k0,k1,k2,k3)

   If (StrLen(x) = 16)              ; full length last message block
   {
      u := u ^ l0                   ; l-key modifies last state
      v := v ^ l1
      XCBCstep(u, v, x, k0,k1,k2,k3)
   }
   Else {                           ; padded last message block
      u := u ^ m0                   ; m-key modifies last state
      v := v ^ m1
      x = %x%100000000000000
      XCBCstep(u, v, x, k0,k1,k2,k3)
   }
   Return Hex8(u) . Hex8(v)         ; 16 hex digits returned
}

XCBCstep(ByRef u, ByRef v, ByRef x, k0,k1,k2,k3)
{
   StringLeft  p, x, 8              ; Msg blocks
   StringMid   q, x, 9, 8
   StringTrimLeft x, x, 16
   p = 0x%p%
   q = 0x%q%
   u := u ^ p
   v := v ^ q
   TEA(u,v,k0,k1,k2,k3)
}

Hex8(i)                             ; 32-bit integer -> 8 hex digits
{
   format = %A_FormatInteger%       ; save original integer format
   SetFormat Integer, Hex
   i += 0x100000000                 ; convert to hex, set MS bit
   StringTrimLeft i, i, 3           ; remove leading 0x1
   SetFormat Integer, %format%      ; restore original format
   Return i
}

Hex(ByRef b, n=0)                   ; n bytes data -> stream of 2-digit hex
{                                   ; n = 0: all (SetCapacity can be larger than used!)
   format = %A_FormatInteger%       ; save original integer format
   SetFormat Integer, Hex           ; for converting bytes to hex

   m := VarSetCapacity(b)
   If (n < 1 or n > m)
       n := m
   Loop %n%
   {
      x := 256 + *(&b+A_Index-1)    ; get byte in hex, set 17th bit
      StringTrimLeft x, x, 3        ; remove 0x1
      h = %h%%x%
   }
   SetFormat Integer, %format%      ; restore original format
   Return h
}