Whatever happened to SHA-256 support in Git?

Whatever happened to SHA-256 support in Git?

As a worked example, Australia's Information Security Manual states

Only hashing algorithms from the SHA-2 family are approved for use. When using SHA-2 for hashing, an output size of at least 224 bits is used, preferably SHA-384.

To use Git you cannot make any claim that hashing in Git contributes to addressing your organisation's threat model: say the threat of subversion of the repository. Then apply for an exception, arguing that Git's use of SHA-1 is out-of-scope as it is not implicated in any threat model. You may then be asked to show how the threat of subversion of the repository is countered, which could be GPG-signing each commit from a key only held on a trusted processor (eg, a Yubikey).

Of course this application for an exception may not be successful: not every organisation's security policy makers may have a deep technical understanding; not every application for an exception may fully address the threat model; and there may be a overarching policy of limiting exceptions in fields with large and widespread consequences, such as the supply chain threat from subversion of software builds.