Talk on reverse engineering/cracking DigiCipher 2

[remlap]

 

[Vipersan]

WoW ..
Is this guy still walking around ..
..or has he had a visit from men in black suits with earpieces ?
I'm seriously impressed.
Beats the hell out of the Royal institute Christmas lectures..
;)

Been a while but I was fully conversant in 6502 back in my yoof..

Still own a copy of programming the 6502 by Rodnay Zaks
lol

btw ..I'm NOT advocating the stealing of proprietory content..
I am simply applauding the resourcefulness and intelligence behind the process.

 

[2cvbloke]

Impressive stuff, didn't understand 99% of it, but, he got there in the end, but he is right, there's naff-all good on TV these days...

 

[Vipersan]

Impressive stuff, didn't understand 99% of it, but, he got there in the end, but he is right, there's naff-all good on TV these days...

Can't pretend to understand a lot of it myself ..
Though I'd like to think I can improve on on 1% ...
sayyy 50% ..
mostly the cpu language ..and the physical processes ..
But DES and key encryption is well beyond me ..
The XOR processes however I sort of get..
This was my favourite 6502 command ..and one that made it possible to cram a lot of processes into small spaces back when I wrote games for Comodore.
;)
I used XOR or 'bit flipping' to create small algo's for 'pseudo sprite' images on the VIC20

 

[archive10]

I used XOR or 'bit flipping' to create small algo's for 'pseudo sprite' images on the VIC20

.from   EQUW 0
.to     EQUW 0
.size   EQUB 0
.sprite EQUW 0

; set from, to, size and sprite when calling

.move_sprite
     LDY #0
     LDX #size
     INX
.loop1
     LDA (from),Y
     EOR (sprite),y  
     STA (from),Y
     LDA (to),Y
     EOR (sprite),Y
     STA (to),Y
     INY
     DEX
     BNE loop
     RTS

or something like that. Haven't done this in, erhm, 30 (?) years...

 

[Vipersan]

.from   EQUW 0
.to     EQUW 0
.size   EQUB 0
.sprite EQUW 0

; set from, to, size and sprite when calling

.move_sprite
     LDY #0
     LDX #size
     INX
.loop1
     LDA (from),Y
     EOR (sprite),y
     STA (from),Y
     LDA (to),Y
     EOR (sprite),Y
     STA (to),Y
     INY
     DEX
     BNE loop
     RTS

or something like that. Haven't done this in, erhm, 30 (?) years...

Very very similar ..
I've forgotten so much over the tears since then ..
for me too ..well over 30 years..
Back then we had no compilers either ..and unlike the C64 which had sprite registers ..
I had to write them from scratch for the Vic 20

So ..one would bitmap the entire screen area ..then generate the sprite ..and this included bit collision detection ..without neccessarily altering the bitmapped background ..
ahh the memories of yoof..
rgds
VS

 

[battenfan]

For a popsci introduction and the history of encryption I recommend reading Simon Singh's Code Book. Very entertaining.