borgbackup/borg

unusual blake2b usage, adopt blake3?

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#8,867 opened on May 21, 2025

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 (10 comments) (0 reactions) (1 assignee)Python (732 forks)batch import
breakingcmd: transferhelp wantedsecurity

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Description

This is from master branch (same in 1.4-maint):

def blake2b_256(key, data):
    return hashlib.blake2b(key+data, digest_size=32).digest()

It is one of the chunkid hashes borg uses.

The usage there is unusual, the python docs rather suggest:

def blake2b_256(key, data):
    return hashlib.blake2b(data, key=key, digest_size=32).digest()

Contributor guide

Research direction
Investigate the differences between blake2b and blake3, replace the function with the correct API using blake2b or implement blake3 support, and ensure tests pass.
Tech stack
python
Domain
backend
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Python
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75