MD5Calc Guides & Examples
Practical, no-fluff documentation for MD5Calc — written by people who hit the problems first.
About MD5Calc
What md5calc computes, which algorithms run in pure JavaScript and which use the Web Crypto API, and what a checksum can and cannot prove.
MD5Calc Changelog
Dated changes to md5calc: the move to the shared site template, and the new HMAC, file hash and comparison tools that its description had promised.
HMAC vs a Plain Hash: Webhook Signatures and Length-Extension
Why signing a message needs HMAC rather than hash(key + message), how webhook signatures are verified, the exact-bytes rule, and which algorithms the calculator supports.
Verify a Download Checksum: What a Match Does and Does Not Prove
How to check a file against a published SHA-256, which tool to use, the three reasons a correct file fails the check, and why a checksum from the same page is weak evidence.
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