[UB1-831] FPE Decrypt Fix (!9) · Merge requests · ubiqsecurity / ubiq-python

Ian Freshwater requested to merge UB1-831_decrypt_fix into master Jan 17, 2023

When decrypting the key number the algorithm needed fixed. Calling int(s[0]) caused an invalid literal for int() with base 10: '&' error.

Updated the function based on the Java library's implementation decode_keynum.

Produced successful round trip with multiple strings, including the one that started this issue!

Sharai Attenburrow => &-|:`l -B^%Nk]P$Z\ => Sharai Attenburrow
after 3 key rotations
Sharai Attenburrow => @&2?.w >QyN:Lc/42= => Sharai Attenburrow

Edited Jan 17, 2023 by Ian Freshwater

[UB1-831] FPE Decrypt Fix