Hi LinkinStar, There were several more replies from others, please see in the list archive if you're not subscribed:
https://www.openwall.com/lists/oss-security/ On Thu, Sep 26, 2024 at 10:10:38AM +0800, LinkinStar wrote: > Because *Gravatar recommends using sha-256*, we believe there must be a > reason for its modification. Since the official recommendation is to change > the encryption method, why not implement it according to the official > requirements? You must admit that sha-256 is more difficult than md5, even > if only slightly. Although this may not completely solve the problem, I > believe following the official recommendation would be marginally better, > wouldn't it? So I think this fix itself is acceptable. The change is fine - just don't call it a security fix. Also, this is hashing and not encryption. Others pointed out that Gravatar's recommendation is just that - not a specification - so unless you need interoperability with other servers implementing Gravatar, you can do better than SHA-256. Specifically, use of a keyed hash such as HMAC-SHA256 was suggested and makes sense to me - as long as the key is generated from a CSPRNG (such as /dev/urandom) and is large enough (such as 32 bytes). Alexander
