Heh, no, actually the book that Katherine links to really is very good. Great narrative without getting too technical - excellent holiday reading. Much like In search of Schrodinger’s cat if quantum theory is your thing.

Anyway, the point I was trying to make is that the key itself is not necessarily the weakest link in the chain.

As a trite example, the Caesar Cypher is a simple encryption technique that moves each letter along the alphabet by a set number - that number being the key. So with a key of two, a becomes c, j becomes l, etc. The problem here is that it’s very vulnerable to frequency analysis in that given a large enough body of encrypted text, replacing the most common encrypted letter with e and so on will usually either reveal the plain text or enough of it to guess the rest.

Finding these sorts of shortcuts is usually how encryption methods are broken.

It sounds a bit like burying your treasure deeper and deeper in the ground, only to find out that your enemies are buying bigger and bigger shovels…

: P

Anyway, you don’t necessarily need the key to decrypt the data. A lot of research into breaking encryption targets the actual encryption method rather than trying to figure out what the key is…