In the Flickr API docs, you need to find the MD5 sum of a string to generate the [api_sig] value.
How does one go about generating an MD5 sum from a string?
Flickr's example:
string: 000005fab4534d05api_key9a0554259914a86fb9e7eb014e4e5d52permswrite
MD5 sum: a02506b31c1cd46c2e0b6380fb94eb3d