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In the examples shown, replace "X.Y" with your app's PHP version [for example, "7.2"].
The mcrypt extension is an interface to the mcrypt cryptography library. This extension is useful for allowing PHP code using mcrypt to run on PHP 7.2+.
The mcrypt extension is included in PHP 5.4 through PHP 7.1. It was removed from PHP 7.2 and moved to an unofficial PECL extension because the mcrypt library is no longer maintained.
For PHP 7.2+, PHP instead uses libsodium as a cryptography library. ServerPilot builds PHP 7.2+ with the official libsodium extension. New PHP code should be written to use libsodium rather than mcrypt.
Installing mcrypt on PHP 5, PHP 7.0, and PHP 7.1
You do not need to install the mcrypt extension on PHP 5, 7.0, or 7.1. ServerPilot builds these PHP versions with the mcrypt extension so it is always available.
Installing mcrypt on PHP 7.2, 7.3, or 7.4
To install this extension on PHP 7.2 through 7.4, run the following commands as your server's root user:
sudo apt-get -y install gcc make autoconf libc-dev pkg-config sudo apt-get -y install libmcrypt-dev sudo pecl7.2-sp install --nodeps mcrypt-snapshot
When you are shown the prompt
libmcrypt prefix? [autodetect] :
Press Enter to autodetect.
Once installed, create a configuration file for the extension and restart PHP by running the following commands as root:
sudo bash -c "echo extension=mcrypt.so > /etc/php7.2-sp/conf.d/mcrypt.ini" sudo service php7.2-fpm-sp restart
Verifying mcrypt Is Installed
You can check that the extension was installed with this command:
php7.2-sp -i | grep mcrypt
The output will look like this:
$ php7.2-sp -i | grep mcrypt /etc/php7.2-sp/conf.d/mcrypt.ini, Registered Stream Filters => zlib.*, convert.iconv.*, bzip2.*, string.rot13, string.toupper, string.tolower, string.strip_tags, convert.*, consumed, dechunk, mcrypt.*, mdecrypt.* mcrypt mcrypt support => enabled mcrypt_filter support => enabled mcrypt.algorithms_dir => no value => no value mcrypt.modes_dir => no value => no value
Uninstalling the Mcrypt Extension
To uninstall this extension, as root run the commands:
sudo rm /etc/phpX.Y-sp/conf.d/mcrypt.ini sudo peclX.Y-sp uninstall mcrypt
Next, restart PHP-FPM with the command:
sudo service phpX.Y-fpm-sp restart
Last updated: October 8, 2018
- Introduction
- Installing/Configuring
- Requirements
- Installation
- Runtime Configuration
- Resource Types
- Predefined Constants
- Mcrypt ciphers
- Mcrypt Functions
- mcrypt_create_iv — Creates an initialization vector [IV] from a random source
- mcrypt_decrypt — Decrypts crypttext with given parameters
- 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 — 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_init — This function initializes all buffers needed for encryption
- mcrypt_generic — This function encrypts data
- mcrypt_get_block_size — Gets the block size of the specified cipher
- mcrypt_get_cipher_name — Gets 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 — Gets the key size of the specified cipher
- mcrypt_list_algorithms — Gets an array of all supported ciphers
- mcrypt_list_modes — Gets an array of all supported modes
- mcrypt_module_close — Closes 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
- mdecrypt_generic — Decrypts data
Kyle T ¶
4 years ago
This was posted before by another user but has been downvoted. I just wanted to confirm that we suffered massive performance issues related to mcrypt on CentOS [PHP 5.6.32] that are not present in other flavors of Linux.
A sampling of 25,000 encrypts/decrypts takes 4-5x longer when running mcrypt on Centos 7 as compared to Ubuntu. Switching out mcrypt for OpenSSL on Centos will result in a massive increase in performance.
For lower traffic website it can be negligible, but when you start seeing significant traffic/load it will quickly bring down a server.
Maarten Malaise ¶
12 years ago
people using phpmyadmin are redirected to this manual if they don't have mcrypt installed. If you want to install mcrypt on debian, first check your php version:
yourserver# php --version
Then install the appropriate version of mcrypt [php5-mcrypt if your php version is 5.x]
yourserver# apt-get install php4-mcrypt
...or...
yourserver# apt-get install php5-mcrypt
Anonymous ¶
10 years ago
These are two simple functions I built for 256-bit encryption/decryption with mcrypt. I've decided to use MCRYPT_RIJNDAEL_128 because it's AES-compliant, and MCRYPT_MODE_CBC. [ECB mode is inadequate for many purposes because it does not use an IV.]
This function stores a hash of the data to verify that the data was decrypted successfully, but this could be easily removed if necessary.