mcrypt_create_iv
mcrypt_ecb
Mcrypt Functions
PHP Manual

# mcrypt_decrypt

(PHP 4 >= 4.0.2, PHP 5)

mcrypt_decrypt — Decrypts crypttext with given parameters

### Description

string mcrypt_decrypt ( string `$cipher` , string `$key` , string `$data` , string `$mode` [, string `$iv` ] )

Decrypts the `data` and returns the unencrypted data.

### Parameters

`cipher`

  One of the `MCRYPT_ciphername` constants, or the name of the algorithm as string.

`key`

  The key with which the data was encrypted. If the provided key size is not supported by the cipher, the function will emit a warning and return `FALSE`

`data`

  The data that will be decrypted with the given `cipher` and `mode`. If the size of the data is not n * blocksize, the data will be padded with '\0'.

`mode`

  One of the `MCRYPT_MODE_modename` constants, or one of the following strings: "ecb", "cbc", "cfb", "ofb", "nofb" or "stream".

`iv`

  Used for the initialization in CBC, CFB, OFB modes, and in some algorithms in STREAM mode. If the provided IV size is not supported by the chaining mode or no IV was provided, but the chaining mode requires one, the function will emit a warning and return `FALSE`.

### Return Values

Returns the decrypted data as a string or `FALSE` on failure.

### Changelog

Version | Description
--- | ---
5.6.0 | Invalid `key` and `iv` sizes are no longer accepted. mcrypt_decrypt() will now throw a warning and return `FALSE` if the inputs are invalid. Previously keys and IVs were padded with '\0' bytes to the next valid size.

### See Also

- mcrypt_encrypt() - Encrypts plaintext with given parameters

mcrypt_create_iv
mcrypt_ecb
Mcrypt Functions
PHP Manual