Mcrypt
PHP Manual

Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

Mcrypt can operate in four block cipher modes (CBC, OFB, CFB, and ECB). If linked against libmcrypt-2.4.x or higher the functions can also operate in the block cipher mode nOFB and in STREAM mode. Below you find a list with all supported encryption modes together with the constants that are defines for the encryption mode. For a more complete reference and discussion see Applied Cryptography by Schneier (ISBN 0-471-11709-9).

Some other mode and random device constants:

MCRYPT_ENCRYPT ( integer )
MCRYPT_DECRYPT ( integer )
MCRYPT_DEV_RANDOM ( integer )
MCRYPT_DEV_URANDOM ( integer )
MCRYPT_RAND ( integer )


Mcrypt
PHP Manual