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Looks awesome, so long as its easy to ensure attackers can't quietly make you use a weak hash. Some JWT implementations quietly allowed the "none" algorithm whi

Looks awesome, so long as its easy to ensure attackers can't quietly make you use a weak hash. Some JWT implementations quietly allowed the "none" algorithm which allowed an attacker to forge creds [1]. Any similar "pluggable" system needs to learn fro this and be careful to avoid letting attackers pick weak algorithms. [1] https://auth0.com/blog/critical-vulnerabilities-in-json-web-token-libraries/ https://auth0.com/blog/critical-vulnerabilities-in-json-web-...

_prometheus 10y ago
That's right. It's really important to make sure there is restrictions on what hashes to use if your system is receiving hashes and only checking them for self-consistency. Particularly relevant is "Crypto Extensibility" (formats and protocols to be able to extend a protocol), vs "Crypto Agility" (the use of Crypto Extensibility to use simultaneously a large variety of algorithms, with the key feature that one can be downgraded to an old/possibly broken hash. AGL describes it well here: https://www.imperialviolet.org/2016/05/16/agility.html https://www.imperialviolet.org/2016/05/16/agility.html --- I've filed https://github.com/multiformats/multihash/issues/70 https://github.com/multiformats/multihash/issues/70 to track this.