gchq / CyberChef

The Cyber Swiss Army Knife - a web app for encryption, encoding, compression and data analysis

Home Page:https://gchq.github.io/CyberChef

Geek Repo:Geek Repo

Github PK Tool:Github PK Tool

Bug report: 32 and 64-bit fletcher checksums seem to be incorrect

b-engler opened this issue · comments

Describe the bug
Fletcher-32 Checksum and Fletcher-64 Checksum algorithms seems not to be working as expected when using the "Generate all hashes" operation. Similar issue was reported last year in 1316.

To Reproduce
As an example, I have compared the results of the "Generate all hashes" operation with the online service Convertcase.com. Fletcher-16 is identical, while Fletcher-32 is different. More can be seen in the screenshot. As mentioned, the Fletcher-64 checksum calculation does not seem to work either. I used the "Raw Bytes" encoding for the input characters (by default adjusted).

Expected behaviour
The Fletcher-32 for "security" should be 0x0f5a0378.
The Fletcher-64 for "security" should be 0x00000f5a00000378.

Screenshots
CyberChef vs. Convertcase.com
Fletcher_Checksum_Issue

Desktop:

  • OS: Kali Linux
  • Browser: Google Chrome 18.0.5993.70 (Official Build) (64-bit)
  • CyberChef version: 10.5.2

Additional context
It might also be that the Convertcase.com implementation is wrong.
Is the reported bug (1316) fixed and the latest CyberChef version (10.5.2) working properly in this regard?