In PHP, what is the difference between hash and mhash?

I'm wondering what is the difference between the hash extension and the mhash extension?

When should I choose one ov开发者_运维技巧er another and why?

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Never mind, I just saw this on the mhash Introduction.

Note: This extension is obsoleted by Hash.

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Mhash manual:

This extension is obsoleted by Hash.