DRAFT: RSA SHA1 signature support is insecure

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#2,399 3 comments 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
35/100
Issue type
Feature
Clarity
Needs clarification
Activity status
Active
Tech stack
go

Research direction

No files or tests are named. Start by tracing how apko verifies APKINDEX and .apk signatures, then review the existing RSA and RSA256 handling alongside the repository compatibility constraints. Done should be defined around communicating RSA-SHA1 weakness while preserving a managed path for repositories that still require it.

Written by the indexing model from the issue text.

Description

Currently apk-tools, apko, and melange support verifying APKINDEX and .apk signatures of types:

  • RSA - RSA signature using SHA1 message digest
  • RSA256 - RSA signature using SHA256 message digest

apko & melange are planning to add support for verifying APKINDEX and .apk signatures using:

  • ML-DSA-86 type signature

Universally RSA-SHA1 signatures are no longer considered secure and are being universally withdrawn and removed.

Wolfi & Chainguard apk repositories transitioned to RSA256 signatures on 2025-01-30.

apko & melange would like to add warnings, add security levels, and remove weak verification, but:

  • alpinelinux.org repositories are still signed with RSA-SHA1
  • JFrog Artifactory repositories are still signed with RSA-SHA1

Users may want to know this, and yet need to continue to use those, and have a managed upgrade path.

Dominant language
Go
Stars
1.7k
Forks
228
Avg merge
1d 3h
Merged PRs (30d)
62

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