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Topic: Need EAC log hash algorithm (Read 4383 times) previous topic - next topic
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Need EAC log hash algorithm

Can anyone here share the details of the EAC hash appearing at the end of the generated .log files?  SHA-512 seems obvious as it is 512 bits, but I can't reproduce the checksum.  This really has me stumped.

Reproducing EAC's self-hash also requires knowing how to deal with the hash space itself since it obviously can't be included in the calculation.  I've tried skipping it.  I've tried setting the bytes to different values.  No joy.

Right now the only way to verify EAC logs against their hashes is EAC's checklog.exe tool which requires an EAC installation.
I would like to do this check without the EAC dependency.

Re: Need EAC log hash algorithm

Reply #1 –
It requires just one additional dependent file. Even still, the EAC install is minimal.

If the algorithm were to be known, then there would be no point in having it.

Re: Need EAC log hash algorithm

Reply #2 –
An install is still an install.  Installs are bad.  Portable is good.

The point would be the same as why lame and flac have internal checksums - data integrity.  If the author also wishes to deter tampering, I will respect that.

Re: Need EAC log hash algorithm

Reply #4 –
> Also?

Not sure the question so I'll say thanks for the quick reply and ask if you can directly confirm the author's intent on keeping the algorithm a secret?  I would go to the forums there to confirm, but my German is a little rusty.

Not having this feature won't kill my product, but it will be a glaring hole.

Re: Need EAC log hash algorithm

Reply #6 –
Thanks but that link is for the track CRC-32 values (32 bits), not the log hash (512 bits).  In fact, my product already verfies those CRC-32's against the flacs in the same directory.  Verifying the log hash itself seemed easy in comparison.  Ha.

Re: Need EAC log hash algorithm

Reply #7 –
Quote from: Nongorilla on
An install is still an install.  Installs are bad.  Portable is good.
So copy the checklog.exe somewhere else and use it portable. What's the problem?

Re: Need EAC log hash algorithm

Reply #8 –
checklog.exe itself has dependencies that require the install.  Plus that would mean my product would be redistributing an EAC product without permission.  Dependencies are evil.

Re: Need EAC log hash algorithm

Reply #9 –
What's the point in verifying the log hash
Quote from: Nongorilla on
The point would be the same as why lame and flac have internal checksums - data integrity.

Why care about log integrity?

Re: Need EAC log hash algorithm

Reply #10 –
Quote from: Nongorilla on
checklog.exe itself has dependencies that require the install.
You appear to have a penchant for making erroneous assumptions.  Presenting slipshod opinions as fact would be another. :)

Re: Need EAC log hash algorithm

Reply #11 –
My attempt to run CheckLog.exe from a system without EAC failed.  I actually did try it.  Perhaps it is a simple fix, but this dependency is still probably a deal breaker.

I have seen other examples of self-hashes on logs & digest files with known algorithms so I don't think it is fair to characterize my statements as "erroneous assumptions" & "slipshod opinions".

So it looks like my well is already poisoned here on my second post, but here is a link anyway to my freeware media diagnostics tool that has everything except the log hash check:

https://mediags.codeplex.com/

Re: Need EAC log hash algorithm

Reply #12 –
The topic was DOA.  I had thought about closing it after my initial reply.

PS: You might want to reconsider your use of the term product so that people don't get the impression that you're making something to sell.

PPS:
Quote
All this knowledge is stored in the FormatDomain.dll library available on the Downloads tab along with front-end executables for the products.
Quote from: Nongorilla on
Dependencies are evil.
The irony: it burns so.

PPPS:
Chris Myden's moronic "uber-standard" baby has risen from the dead?
<facepalm>
https://hydrogenaud.io/index.php/topic,65696.0.html

Re: Need EAC log hash algorithm

Reply #13 –
Quote from: Nongorilla on
Not sure the question so I'll say thanks for the quick reply and ask if you can directly confirm the author's intent on keeping the algorithm a secret?
Quote from: Nongorilla on
Right now the only way to verify EAC logs against their hashes is EAC's checklog.exe tool which requires an EAC installation.
I would like to do this check without the EAC dependency.

The developer, Andre Wiethoff, hasn't created an account here so I'm passing on his reply.

Quote
Of course it is a secret.

But some people would like to check their logs afterwards without an EAC install, so I created a web page where it is possible to upload log files and the online checker will tell whether it is fine or not. As the web page just performs the submission of a form (with file upload), it isn't very hard to implement that within e.g. a .NET application.

The URL for the checker web page is http://www.exactaudiocopy.de/log/checklog.html

edit: used different (wrong) original Nongorilla quote
korth

Re: Need EAC log hash algorithm

Reply #14 –
Well that nails it then.  Thanks, Korth for contributing.  Big help.  All I wanted was a confirmation from the author.  That should not be such a terrible thing to ask for.

Should I be expecting more cheap shots now?  I know my innate skepticism can grind some the wrong way, but still.

Re: Need EAC log hash algorithm

Reply #16 –
Quote from: Nongorilla on
My attempt to run CheckLog.exe from a system without EAC failed.  I actually did try it. 
you need to use two  files : CheckLog.exe & HelperFunctions.dll

Re: Need EAC log hash algorithm

Reply #18 –
Does this mean that I have permission to redistribute these 2 files?  Or would my customers download and extract?  These apps are not just for the other computer in my basement - I have customers.  Few and far between, but my work on the Mediags project is customer driven.

The earlier point is valid about my project's dependency of the front ends on the FormatDomain.dll library.  That dependency should be eliminated and none added.  IMO, portable apps are ideal when they are stand-alone or as close as possible.  You haven't changed my mind on that yet.

And thanks, Mr.Fox, for posting the CheckLog.exe fix.

Re: Need EAC log hash algorithm

Reply #19 –
I wonder why there is such a hostile attitude towards Nongorilla. He is simply asking for the possibility of an alternative solutions to do log check without having to install the full EAC.
I really don't think we should deter people from asking for small help/information by greeting them with such a negative attitude.

I would understand if OP had posted som BS statements as hardcore facts  or hadn't done any research at all and was just leeching/waisting Peopless time. But this is a honest question.

This attitude is coming from a "global moderator" so can assume that is how the official way to responds to people is now on HA?
Nongorrilla was polite through this thread which is more than I would say about certain other people's "better than thou"  belittlement attitude.

Fox and Korth was the only one actually provide in usable information on the topic.
Sven Bent - Denmark

Re: Need EAC log hash algorithm

Reply #20 –
Fuck me.

EAC's algorithm is intentionally kept secret.  I know this as a fact and I don't speak German. Sorry I didn't get it notarized.
EAC is closed source.
The executable used to check logs has one dependency. They can be extracted without having to perform an evil installation.
The OP's idiotic zealotry about how a hardware-dependent program should behave is not really germane to the discussion.

So other than cry foul about tone while completely overlooking that information was actually provided by people who were not on your white list, what have you done to progress the discussion?

This really should have been taken up with the author of the program, especially if we're now attempting to speculate on distribution.

This topic will now close.