Simon Willison's Weblog: hashes

Redis weekly update #1 - Hashes and... many more!

2010-03-13T00:06:22+00:00

Redis weekly update #1 - Hashes and... many more!

Hashes were the big missing data type in Redis—support is only partial at the moment (no ability to list all keys in a hash or delete a specific key) but at the rate Redis is developed I expect that to be fixed within a week or two.

Tags: hashes, keyvaluestores, nosql, redis

Researchers Show How to Forge Site Certificates

2008-12-30T15:27:33+00:00

Researchers Show How to Forge Site Certificates

Use an MD5 collision to create two certificates with the same hash, one for a domain you own and another for amazon.com. Get Equifax CA to sign your domain’s certificate using the outdated “MD5 with RSA” signing method. Copy that signature on to your home-made amazon.com certificate to create a fake certificate for Amazon that will be accepted by any browser.

Tags: collisions, ed-felten, equifaxca, hashes, md5, security, ssl

Django snippets: Sign a string using SHA1, then shrink it using url-safe base65

2008-08-27T22:18:49+00:00

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.

Tags: base65, cookies, cryptography, django, django-snippets, hashes, python, security, sha1, signedcookies, urls