[hackers] Re: [hackers][new tool][gcrypt]

From: Գասպար Վարդանյան <gaspar.vardanyan.mailbox_AT_gmail.com>
Date: Thu, 20 Feb 2020 15:38:04 +0300

>thanks for sharing! Do you have any theoretical groundwork for your
>algorithm, arguing for example why the file encryption tool is safe
>against e.g. watermark attacks?

gcrypt generates a hash for the password and encrypts the file using that hash. gcrypt replaces every byte in the input file depending on the hash and the previous byte in the file. So if the file contains something like «AFFFFF» and you replace A with B in the file, gcrypt will generate different result for «FFFFF». I think the only way to crack gcrypted file is the BruteForce method. The output file doesn't have a certain structure and gcrypt doesn’t stop decryption when the password is wrong, it generates a garbage file and might generate wrong signatures. The overlapping probability of the randomly generated decryption hash and original hash is (1 / (256 factorial)). Some tests on gcrypt:  https://imgur.com/a/X17uvVG  (might be nubic test). I don’t have any theoretical groundworks for my algorithm, but I can test what my algorithm does, and I think it’s safe (might be you can find any drawbacks in my algorithm, please tell me). gcrypt is included in BlackArch’s arsenal ( https://blackarch.org/crypto.html ) and I think it’s worth testing gcrypt.
>Few notes:
>- Add a Makefile. It's the correct way to build something.
>- Add a manual page please.
>- Your gcrypt.h includes too much C headers that are not required for
>the declarations provided here. Since you use size_t only <stddef.h>
>would be required here.
>- Macros in gcrypt.c... I don't think there is a real reason to
>implement all that code in macros.
Thank you for advices.
- Yes, I’m sure that it’s the correct way to build something, but I don’t know makefile’s language, I’ll learn it and try to write a Makefile for gcrypt.
- Manual pages, groff/troff… I’ll try to make a manual page for gcrypt.
- The only unused header was the stdint.h and I already removed it.
- Hmm… I like macros, they are faster than functions and I try to implement everything usign macros rather than function.
P.S. Sorry for my poor English.
Received on Thu Feb 20 2020 - 13:38:04 CET

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