[Cuis-dev] Hello and MD5 hash weird behavior

[Luciano Notarfrancesco]

Hi Jeroen,
I just tried it on mac with the latest Cuis and I get the same results as
you. However, using MD5NonPrimitive instead of MD5 I get the correct result
(note that you will get a message not understood exception, because it
sends the message #doWithIndex: that doesn’t exist, you just need to
replace it with #withIndexDo:).


On Sun, Nov 9, 2025 at 05:53 Jeroen Kouwer via Cuis-dev <
cuis-dev at lists.cuis.st> wrote:

> Hello,
>
> I'm new to this list and new to Smalltalk development. I'm a software
> engineer by profession and grew up with Unix (SVR4), Pascal and C. Since
> then I've moved to Linux, Java and C++ and although I've read about
> Smaltalk and I have been intrigued with the idea behind it, I've never
> actually programmed in it.
>
> Until now.
>
> I've started The Cuis Book, together with the SBE and the Cuis Cook
> Book, and am currently trying to solve the first year of the Advent of
> Code (2015) in Smalltalk (the Cuis version [1]). The first three days
> went really well. The challenge came on day four: having to use MD5 hash
> calculation. Cuis, out of the box, doesn't come with an MD5 class. A
> little searching led me to the Cryptography package [2] and I installed
> the package using the File List.
>
> Side note: This package does not define a feature, so when next starting
> the image (provided having saved it) it throws you into the debugger.
> The package is recognized, but when checking for new versions it finds
> out that there's no feature defined (nil is not a valid feature) and
> this part of opening the image cannot handle that:
> ```
> UndefinedObject(Object)>>doesNotUnderstand: #isLaterThan:
> [] in ChangeSet class>>installNewUpdates:
> ...
> ```
> However, this can be solved by saving the package (open Installed
> Packeges); saving the package apparently adds the category as feature to
> the *.pck.st.
>
> Back to Cryptography and feature Cuis-System-Hashing (from the
> Cryptography package [2]): I cannot get the MD5 class to behave as I
> expect it to behave. I expect that each call to hashMessage with the
> same message results in the same hash, which it does in Squeak and Pharo
> (after some frustration I did some checking).
>
> After having loaded the package for the first time and executing it the
> results are as expected:
> ```
> ((MD5 new) hashMessage: 'abcdef609043') hex.
>   '000001DBBFA3A5C83A2D506429C7B00E' .
> ```
> Executing it a second time results in:
> ```
> ((MD5 new) hashMessage: 'abcdef609043') hex.
>   'D1CE4AB38D6D9DC0E1FF789725EFA294' .
> ```
> Each consecutive execution results in a different value, which is not
> what I expected!
>
> (I've managed to solve day four by resorting to Squeak :o, sorry...)
>
> Does anyone has an idea why this calculation keeps on producing new
> values on each execution?
>
> Regards,
> Jeroen Kouwer
>
> P.S. I have observed the same behavior with Cuis 7.2 [3]
>
>
> [1] https://github.com/Cuis-Smalltalk/Cuis-Smalltalk-Dev
>
> [2] https://github.com/garduino/Cuis-Smalltalk-Cryptography
>
> [3] https://github.com/Cuis-Smalltalk/Cuis7-2
>
> --
> Cuis-dev mailing list
> Cuis-dev at lists.cuis.st
> https://lists.cuis.st/mailman/listinfo/cuis-dev
>
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