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PHP Functions

Function: mcal_week_of_year

(PHP 4, PECL)

mcal_week_of_year --  Returns the week number of the given date

Description

int mcal_week_of_year ( int day, int month, int year )

mcal_week_of_year() returns the week number of the given date.

LXX. Mcrypt Encryption Functions

Introduction

This is an interface to the mcrypt library, which supports a wide variety of block algorithms such as DES, TripleDES, Blowfish (default), 3-WAY, SAFER-SK64, SAFER-SK128, TWOFISH, TEA, RC2 and GOST in CBC, OFB, CFB and ECB cipher modes. Additionally, it supports RC6 and IDEA which are considered "non-free".

Requirements

These functions work using mcrypt . To use it, download libmcrypt-x.x.tar.gz from http://mcrypt.sourceforge.net/ and follow the included installation instructions. Windows users will find all the needed compiled mcrypt binaries at http://ftp.emini.dk/pub/php/win32/mcrypt/ .

As of PHP 5.0.0 you will need libmcrypt Version 2.5.6 or greater.

If you linked against libmcrypt 2.4.x or higher, the following additional block algorithms are supported: CAST, LOKI97, RIJNDAEL, SAFERPLUS, SERPENT and the following stream ciphers: ENIGMA (crypt), PANAMA, RC4 and WAKE. With libmcrypt 2.4.x or higher another cipher mode is also available; nOFB.

Installation

You need to compile PHP with the --with-mcrypt[=DIR] parameter to enable this extension. DIR is the mcrypt install directory. Make sure you compile libmcrypt with the option --disable-posix-threads .

Runtime Configuration

The behaviour of these functions is affected by settings in php.ini .

Table 1. Mcrypt configuration options

Name Default Changeable Changelog mcrypt.algorithms_dir NULL PHP_INI_ALL Available since PHP 4.0.2. mcrypt.modes_dir NULL PHP_INI_ALL Available since PHP 4.0.2. For further details and definitions of the PHP_INI_* constants, see the Appendix H .

Resource Types

This extension has no resource types defined.

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).

MCRYPT_MODE_ECB (electronic codebook) is suitable for random data, such as encrypting other keys. Since data there is short and random, the disadvantages of ECB have a favorable negative effect.

MCRYPT_MODE_CBC (cipher block chaining) is especially suitable for encrypting files where the security is increased over ECB significantly.

MCRYPT_MODE_CFB (cipher feedback) is the best mode for encrypting byte streams where single bytes must be encrypted.

MCRYPT_MODE_OFB (output feedback, in 8bit) is comparable to CFB, but can be used in applications where error propagation cannot be tolerated. It's insecure (because it operates in 8bit mode) so it is not recommended to use it.

MCRYPT_MODE_NOFB (output feedback, in nbit) is comparable to OFB, but more secure because it operates on the block size of the algorithm.

MCRYPT_MODE_STREAM is an extra mode to include some stream algorithms like WAKE or RC4.

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 ciphers

Here is a list of ciphers which are currently supported by the mcrypt extension. For a complete list of supported ciphers, see the defines at the end of mcrypt.h . The general rule with the mcrypt-2.2.x API is that you can access the cipher from PHP with MCRYPT_ciphername. With the libmcrypt-2.4.x and libmcrypt-2.5.x API these constants also work, but it is possible to specify the name of the cipher as a string with a call to mcrypt_module_open() .

MCRYPT_3DES

MCRYPT_ARCFOUR_IV (libmcrypt > 2.4.x only)

MCRYPT_ARCFOUR (libmcrypt > 2.4.x only)

MCRYPT_BLOWFISH

MCRYPT_CAST_128

MCRYPT_CAST_256

MCRYPT_CRYPT

MCRYPT_DES

MCRYPT_DES_COMPAT (libmcrypt 2.2.x only)

MCRYPT_ENIGMA (libmcrypt > 2.4.x only, alias for MCRYPT_CRYPT)

MCRYPT_GOST

MCRYPT_IDEA (non-free)

MCRYPT_LOKI97 (libmcrypt > 2.4.x only)

MCRYPT_MARS (libmcrypt > 2.4.x only, non-free)

MCRYPT_PANAMA (libmcrypt > 2.4.x only)

MCRYPT_RIJNDAEL_128 (libmcrypt > 2.4.x only)

MCRYPT_RIJNDAEL_192 (libmcrypt > 2.4.x only)

MCRYPT_RIJNDAEL_256 (libmcrypt > 2.4.x only)

MCRYPT_RC2

MCRYPT_RC4 (libmcrypt 2.2.x only)

MCRYPT_RC6 (libmcrypt > 2.4.x only)

MCRYPT_RC6_128 (libmcrypt 2.2.x only)

MCRYPT_RC6_192 (libmcrypt 2.2.x only)

MCRYPT_RC6_256 (libmcrypt 2.2.x only)

MCRYPT_SAFER64

MCRYPT_SAFER128

MCRYPT_SAFERPLUS (libmcrypt > 2.4.x only)

MCRYPT_SERPENT(libmcrypt > 2.4.x only)

MCRYPT_SERPENT_128 (libmcrypt 2.2.x only)

MCRYPT_SERPENT_192 (libmcrypt 2.2.x only)

MCRYPT_SERPENT_256 (libmcrypt 2.2.x only)

MCRYPT_SKIPJACK (libmcrypt > 2.4.x only)

MCRYPT_TEAN (libmcrypt 2.2.x only)

MCRYPT_THREEWAY

MCRYPT_TRIPLEDES (libmcrypt > 2.4.x only)

MCRYPT_TWOFISH (for older mcrypt 2.x versions, or mcrypt > 2.4.x )

MCRYPT_TWOFISH128 (TWOFISHxxx are available in newer 2.x versions, but not in the 2.4.x versions)

MCRYPT_TWOFISH192

MCRYPT_TWOFISH256

MCRYPT_WAKE (libmcrypt > 2.4.x only)

MCRYPT_XTEA (libmcrypt > 2.4.x only)

You must (in CFB and OFB mode) or can (in CBC mode) supply an initialization vector (IV) to the respective cipher function. The IV must be unique and must be the same when decrypting/encrypting. With data which is stored encrypted, you can take the output of a function of the index under which the data is stored (e.g. the MD5 key of the filename). Alternatively, you can transmit the IV together with the encrypted data (see chapter 9.3 of Applied Cryptography by Schneier (ISBN 0-471-11709-9) for a discussion of this topic).

Examples

Mcrypt can be used to encrypt and decrypt using the above mentioned ciphers. If you linked against libmcrypt-2.2.x, the four important mcrypt commands ( mcrypt_cfb() , mcrypt_cbc() , mcrypt_ecb() , and mcrypt_ofb() ) can operate in both modes which are named MCRYPT_ENCRYPT and MCRYPT_DECRYPT, respectively.

Example 1. Encrypt an input value with TripleDES under 2.2.x in ECB mode

<?php
$key = "this is a secret key";
$input = "Let us meet at 9 o'clock at the secret place.";

$encrypted_data = mcrypt_ecb (MCRYPT_3DES, $key, $input, MCRYPT_ENCRYPT);
?>
This example will give you the encrypted data as a string in $encrypted_data .

If you linked against libmcrypt 2.4.x or 2.5.x, these functions are still available, but it is recommended that you use the advanced functions.

Example 2. Encrypt an input value with TripleDES under 2.4.x and higher in ECB mode

<?php
    $key = "this is a secret key";
    $input = "Let us meet at 9 o'clock at the secret place.";

    $td = mcrypt_module_open('tripledes', '', 'ecb', '');
    $iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
    mcrypt_generic_init($td, $key, $iv);
    $encrypted_data = mcrypt_generic($td, $input);
    mcrypt_generic_deinit($td);
    mcrypt_module_close($td);
?>
This example will give you the encrypted data as a string in $encrypted_data . For a full example see mcrypt_module_open() .

Table of Contents mcrypt_cbc  -- Encrypt/decrypt data in CBC mode mcrypt_cfb  -- Encrypt/decrypt data in CFB mode mcrypt_create_iv  --  Create an initialization vector (IV) from a random source mcrypt_decrypt  -- Decrypts crypttext with given parameters mcrypt_ecb  -- Deprecated: Encrypt/decrypt data in ECB mode mcrypt_enc_get_algorithms_name  -- Returns the name of the opened algorithm mcrypt_enc_get_block_size  -- Returns the blocksize of the opened algorithm mcrypt_enc_get_iv_size  -- Returns the size of the IV of the opened algorithm mcrypt_enc_get_key_size  -- Returns the maximum supported keysize of the opened mode mcrypt_enc_get_modes_name  -- Returns the name of the opened mode mcrypt_enc_get_supported_key_sizes  -- Returns an array with the supported keysizes of the opened algorithm mcrypt_enc_is_block_algorithm_mode  -- Checks whether the encryption of the opened mode works on blocks mcrypt_enc_is_block_algorithm  -- Checks whether the algorithm of the opened mode is a block algorithm mcrypt_enc_is_block_mode  -- Checks whether the opened mode outputs blocks mcrypt_enc_self_test  -- This function runs a self test on the opened module mcrypt_encrypt  -- Encrypts plaintext with given parameters mcrypt_generic_deinit  --  This function deinitializes an encryption module mcrypt_generic_end  -- This function terminates encryption mcrypt_generic_init  -- This function initializes all buffers needed for encryption mcrypt_generic  -- This function encrypts data mcrypt_get_block_size  -- Get the block size of the specified cipher mcrypt_get_cipher_name  -- Get the name of the specified cipher mcrypt_get_iv_size  --  Returns the size of the IV belonging to a specific cipher/mode combination mcrypt_get_key_size  -- Get the key size of the specified cipher mcrypt_list_algorithms  -- Get an array of all supported ciphers mcrypt_list_modes  -- Get an array of all supported modes mcrypt_module_close  --  Close the mcrypt module mcrypt_module_get_algo_block_size  -- Returns the blocksize of the specified algorithm mcrypt_module_get_algo_key_size  -- Returns the maximum supported keysize of the opened mode mcrypt_module_get_supported_key_sizes  -- Returns an array with the supported keysizes of the opened algorithm mcrypt_module_is_block_algorithm_mode  -- Returns if the specified module is a block algorithm or not mcrypt_module_is_block_algorithm  -- This function checks whether the specified algorithm is a block algorithm mcrypt_module_is_block_mode  -- Returns if the specified mode outputs blocks or not mcrypt_module_open  -- Opens the module of the algorithm and the mode to be used mcrypt_module_self_test  -- This function runs a self test on the specified module mcrypt_ofb  -- Encrypt/decrypt data in OFB mode mdecrypt_generic  -- Decrypt data

Related Function(s)

  • mcrypt_module_open()
  • mcrypt_cfb()
  • mcrypt_cbc()
  • mcrypt_ecb()
  • mcrypt_ofb()
  • mcrypt_create_iv()
  • mcrypt_decrypt()
  • mcrypt_enc_get_algorithms_name()
  • mcrypt_enc_get_block_size()
  • mcrypt_enc_get_iv_size()
  • mcrypt_enc_get_key_size()
  • mcrypt_enc_get_modes_name()
  • mcrypt_enc_get_supported_key_sizes()
  • mcrypt_enc_is_block_algorithm_mode()
  • mcrypt_enc_is_block_algorithm()
  • mcrypt_enc_is_block_mode()
  • mcrypt_enc_self_test()
  • mcrypt_encrypt()
  • mcrypt_generic_deinit()
  • mcrypt_generic_end()
  • mcrypt_generic_init()
  • mcrypt_generic()
  • mcrypt_get_block_size()
  • mcrypt_get_cipher_name()
  • mcrypt_get_iv_size()
  • mcrypt_get_key_size()
  • mcrypt_list_algorithms()
  • mcrypt_list_modes()
  • mcrypt_module_close()
  • mcrypt_module_get_algo_block_size()
  • mcrypt_module_get_algo_key_size()
  • mcrypt_module_get_supported_key_sizes()
  • mcrypt_module_is_block_algorithm_mode()
  • mcrypt_module_is_block_algorithm()
  • mcrypt_module_is_block_mode()
  • mcrypt_module_self_test()
  • mdecrypt_generic()
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