This function initializes all buffers needed for encryption

mcrypt_generic_end
mcrypt_generic
Mcrypt Functions
PHP Manual

# mcrypt_generic_init

(PHP 4 >= 4.0.2, PHP 5)

mcrypt_generic_init — This function initializes all buffers needed for encryption

### Description

int mcrypt_generic_init ( resource `$td` , string `$key` , string `$iv` )

You need to call this function before every call to mcrypt_generic() or mdecrypt_generic().

### Parameters

`td`

  The encryption descriptor.

`key`

  The maximum length of the key should be the one obtained by calling mcrypt_enc_get_key_size() and every value smaller than this is legal.

`iv`

  The IV should normally have the size of the algorithms block size, but you must obtain the size by calling mcrypt_enc_get_iv_size(). IV is ignored in ECB. IV MUST exist in CFB, CBC, STREAM, nOFB and OFB modes. It needs to be random and unique (but not secret). The same IV must be used for encryption/decryption. If you do not want to use it you should set it to zeros, but this is not recommended.

### Return Values

The function returns a negative value on error: -3 when the key length was incorrect, -4 when there was a memory allocation problem and any other return value is an unknown error. If an error occurs a warning will be displayed accordingly. `FALSE` is returned if incorrect parameters were passed.

### See Also

- mcrypt_module_open() - Opens the module of the algorithm and the mode to be used

mcrypt_generic_end
mcrypt_generic
Mcrypt Functions
PHP Manual