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PHP. Руководство по PHP. 2005

Mcrypt Encryption Functions

Пред.

След.

LXX. Mcrypt Encryption Functions

Введение

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".

Требования

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 PHP5.0.0 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.

Установка

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.

Настройка во время выполнения

-Поведение этих функций зависит от установок в php.ini.

Таблица 1. Mcrypt configuration options

NameDefaultChangeableChangelog
mcrypt.algorithms_dirNULLPHP_INI_ALLAvailable since PHP4.0.2.
mcrypt.modes_dirNULLPHP_INI_ALLAvailable since PHP4.0.2.

Для подробного описания констант

PHP_INI_*, обратитесь к документации функции ini_set().

Типы ресурсов

Данное расширение не определяет никакие типы ресурсов.

Предопределенные константы

-Перечисленные ниже константы определены данным расширением и могут быть

доступны только в том случае, если PHP был собран с

поддержкой этого расширения или же в том случае, если

данное расширение подгружается во время выполнения.

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).

    Примеры

    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.

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

    <?

    $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.

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

    <?

    $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().

    Содержание

    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

    Пред.

    Начало

    След.

    mcal_week_of_year

    Уровень выше

    mcrypt_cbc

  • Отвечу на любые вопросы. С уважением, Дмитрий Владимирович.

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