It's the same as encryption, except it is in a case where the act of encryption the data does not actually protect anything, but instead prevents people interested in said harmless data from decoding / seeing it. A good example is a case where a satellite signal is enrypted, despite all data being public a few minutes later online.
It is a marge of the word "encryption" and "crap", to reflect the negative effects of said encryption.
As far as it is known, this word was first used by UHF-Satcom, and has stuck in the amateur satellite / radioamateur community since then,
An algorithm used to scramble data which makes it unreadable to everyone except the recipient. This is often used by e-commerce sites to secure credit card data. Secure sites use encryption.
South Park's hilarious send-up of bullshit fictional hacking in movies.
Kyle Broflowski can't log onto a message board, but is able to break through the access code by "rewriting the encryptions". He achieves this by typing furiously until the screen reads "Access Granted".
Kyle: Dammit, they've got an access code! I'll rewrite the encryptions!
(types furiously for 5 seconds)
Got it!
(Cartman and Stan look at him incredulously)