PHP crypt() function is a part of PHP string references whose main function is to return a hashed string using some special algorithms. PHP crypt() function is associated with the algorithms like DES, Blowfish or MD5 algorithms for its overall network and cryptographic encryption and decryption of string being passed from the crypt() function. Crypt() function vary from one function to another function in a way that behavior gets transformed accordingly to different operating system. It checks for all the available algorithms or if any need is there to install new algorithm for encryption.
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Syntax:
crypt(str,salt)
There are following constants for crypt() function which have some values set as 0 or 1 depending on whether the given type of crypt constants is available.
First constant which has a two-character salt parameter passed from the alphabet. Also, supports for the values supporting the digits with numbers of uppercase 0-9 and alphabets with upper case A-Z and lower case alphabets like a-z. crypt function will get failed if some invalid characters will be used while passing the salt parameter.
Example: A program to illustrate CRYPT_STD_DES constant.
Code:
<?php if (CRYPT_STD_DES == 1) { echo "Standard DES: ".crypt('educba','string')."\n"; } else { echo "Do not support standard DES.\n"; } ?>
Output:
This constant is a type of extension to the DES based hashing function. If the salt parameter being passed has a nine character string followed by the parameter of 4 bytes, then only the algorithm will get satisfied.
Example: A program to illustrate CRYPT_EXT_DES constant.
Code:
<?php if (CRYPT_EXT_DES == 1) { echo "Extended DES: ".crypt('anu','_D8..dutta')."\n"; } else { echo "It do not support for Extended DES.\n"; } ?>
Output:
This constant MD5 works with hashing function including crypt parallelly with a character of salt parameter having a length of twelve character.
Example: A program to illustrate CRYPT_MD5 constant.
Code:
<?php if (CRYPT_MD5 == 1) { echo "MD5: ".crypt('mansi','$1$trying$')."\n"; } else { echo "Do not support for MD5.\n"; } ?>
Output:
This constant support for the function with salt parameter containing some cost parameter ranging from “$” to 22. If the parameter value does not lie within the specified range, then it will return a string of zero-length. The cost parameter is considered as twice if the base of logarithmic value for the illustrated blowfish-based hashing algorithm. PHP versions of 5 and above supports for the given constant.
Example: A program to illustrate CRYPT_BLOWFISH constant.
Code:
<?php if (CRYPT_BLOWFISH == 1) { echo "Blowfish: ".crypt('sunrise','$1b$08$mkstringexforsaltparam$')."\n"; } else { echo "It do not support for Blowfish.\n"; } ?>
Output:
SHA-256 is a constant which is part of the algorithm with a hash value of sixteen character. If in case the string gets started with the round of $N hen it indicates number of times hashed function gets called and executes with the optimization and cost factor like Blowfish algorithm. Also, if the selection of numbers does not lie outside the range then the next value of the range will get approximation to the closest value of the range.
Example: A program to illustrate CRYPT_SHA256 constant.
Code:
<?php if (CRYPT_SHA256 == 1) { echo "SHA-256: ".crypt('sunfeast','$8$rounds=8000$examplestringforsaltofsalt$')."\n"; } else { echo "It do not support for CRYPT_SHA256.\n"; } ?>
Output:
This is a constant which is prefixed with some value like 6$. If the round function gets started with the value of taken round of number of salts , then it points for the optimized value same as Blowfish function. Also, it can be said that behavior of the constant is same as SHA-256 constant with just some mere differences.
Example: A program to illustrate CRYPT_SHA512 constant.
Code:
<?php if (CRYPT_SHA512 == 1) { echo "SHA-512: ".crypt('things','$9$rounds=9000$xamplestringof90salt$'); } else { echo " It donot support for CRYPT_SHA512 ."; } ?>
Output:
Note: The system with version of 5.3.0 contains implementation of its own type and will use that implementation if that system lacks the install then it will look for the constant and its related algorithm for self-installation and implementation.PHP crypt() function can encrypt the hashed string and is a one directional cryptographic method supporting the mentioned algorithm and it specifically supports for encryption not for decryption that is why it is named as one-directional algorithm.
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