Django snippets: Sign a string using SHA1, then shrink it using url-safe base65. I needed a way to create tamper-proof URLs and cookies by signing them, but didn’t want the overhead of a full 40 character SHA1 hash. After some experimentation, it turns out you can knock a 40 char hash down to 27 characters by encoding it using a custom base65 encoding which only uses URL-safe characters.
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That could be useful. Thanks!
Julian - 28th August 2008 00:17 - #
Oh, and you are sure you don't mean base64?
Julian - 28th August 2008 00:20 - #
Julian: nope, it's base65, and it's something I made up (though I'm sure it's been made up by lots of other people before). It uses all 65 characters that don't need to be encoded to pass in a URL - that's a-z, A-Z, 0-9 and the underscore, hyphen and full-stop.
If you just need some low-security obfuscation to prevent guessability, you could even XOR some of the bytes of your checksum together to shorten it first.
Obviously not recommended for real security needs, though.
dmc - 28th August 2008 09:49 - #
Perhaps you are interested in a reverse SHA-1 search? http://www.sha1-lookup.com
Jens Hafelmeier - 30th August 2008 11:13 - #