This module implements TEA, the Tiny Encryption Algorithm, and some Modes of Use, in Perl and JavaScript. The $key is a sufficiently longish string; at least 17 random 8-bit bytes for single encryption. Crypt::Tea_JS can be used for secret-key encryption in general, or, in particular, to communicate securely between browser and web-host. In this case, the simplest arrangement is for the user to enter the key into a JavaScript variable, and for the host to retrieve that user's key from a database. Or, for extra security, the first message (or even each message) between browser and host could contain a random challenge-string, which each end would then turn into a signature, and use that signature as the encryption-key for the session (or the reply).