手册中加密类的翻译

lsok

Enables you to re-encode data that was originally encrypted with CodeIgniter 1.x to be compatible with the Encryption library in CodeIgniter 2.x. It is only necessary to use this method if you have encrypted data stored permanently such as in a file or database and are on a server that supports Mcrypt. "Light" use encryption such as encrypted session data or transitory encrypted flashdata require no intervention on your part. However, existing encrypted Sessions will be destroyed since data encrypted prior to 2.x will not be decoded.

Why only a method to re-encode the data instead of maintaining legacy methods for both encoding and decoding? The algorithms in the Encryption library have improved in CodeIgniter 2.x both for performance and security, and we do not wish to encourage continued use of the older methods. You can of course extend the Encryption library if you wish and replace the new methods with the old and retain seamless compatibility with CodeIgniter 1.x encrypted data, but this a decision that a developer should make cautiously and deliberately, if at all.

求达人翻译一下,多谢. 另外,其中的"Light"是什么意思?