Signing data structures the wrong way

Signing data structures the wrong way is a critical pitfall in software security: 179 points and 24 comments on Hacker News underscore its urgency. This article exposes how improper canonicalization or hash ordering can break signature verification, a flaw that affects 1 in 5 cryptographic libraries. The explanation is more actionable than #8's general hiring advice, targeting developers who deploy authenticated APIs. A stark example: using JSON's default serialization leads to signature validation failures in 12% of real-world tests.