[PB 4.40] AESEncoder() and Strings

[Little John]

Hi all!

If AESEncoder(@String$, *CipheredString, Len(String$), ?Key, 128, ?InitializationVector)
Debug "Ciphered: "+PeekS(*CipheredString)

So do the data that are produced by AESEncoder() never contain Chr(0), so that it's always safe to use PeekS() like in this example?

Regards, Little John

[netmaestro]

The encoded string will indeed contain zeros, you can't use peeks() on it. If you want to look at it in its raw form you'll have to think of something else.

[Little John]

Hi netmaestro,

thanks for clarifying that!
I hope it will be corrected in the docs.

Regards, Little John

[netmaestro]

Tiny demo to show:

Code: Select all

;; Text encryption test...

key$ = "Four score and seven years ago, and so on and so on"

a$="You can't handle the truth! Son, we live in a world that has walls. And those walls have to be guarded by men with guns."
a$+" Who's gonna do it? You? You, Lt. Weinberg? I have a greater responsibility than you can possibly fathom."
a$+" You weep for Santiago and you curse the Marines. You have that luxury. You have the luxury of Not knowing what I know:"
a$+" that Santiago's death, while tragic, probably saved lives. and my existence, while grotesque and incomprehensible"
a$+" to you, saves lives...You don't want the truth. Because deep down, in places you don't talk about at parties,"
a$+" you want me on that wall. You need me on that wall. We use words like honor, code, loyalty...we use these words"
a$+" As the backbone to a life spent defending something. You use 'em as a punchline. I have neither the time nor the inclination"
a$+" to explain myself to a man who rises and sleeps under the blanket of the very freedom I provide, then questions the manner"
a$+" in which I provide it! I'd rather you just said thank you and went on your way. Otherwise, I suggest you pick up a weapon"
a$+" and stand a post. Either way, I don't give a damn what you think you're entitled to! "

Structure Init_Vector ; I picked an init vector size = cipher blocksize
  byte.a[32]
EndStructure

*initvector.Init_Vector = AllocateMemory(32)

RandomSeed(189470) ; for testing I'm using same init vector every time

For i=0 To 31
  *initvector\byte[i] = Random(255)
Next

*encoded = AllocateMemory(Len(a$))

AESEncoder(@a$,*encoded,Len(a$),@key$,128,*initvector)
For i=*encoded To *encoded+MemorySize(*encoded)
  charlist$+RSet(Str(PeekB(i)&$FF),3,"0")+","
Next
charlist$ = Left(charlist$,Len(charlist$)-1)

Debug "Encoded memory block contains "+Str(CountString(charlist$,"000"))+" zero bytes"

*decoded = AllocateMemory(MemorySize(*encoded))
AESDecoder(*encoded,*decoded,MemorySize(*encoded),@key$,128,*initvector)

result$ = PeekS(*decoded,MemorySize(*decoded))

MessageRequester("",result$, $80)

[Little John]

Tiny demo to show:

Oh yes! We actually should be aware of this, when using AESEncoder().
Thanks again!

Regards, Little John