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How to use PHP's password_hash to hash and verify passwords
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Every now and then I hear the advice "Use bcrypt for storing passwords in PHP, bcrypt rules".
But what is bcrypt? PHP doesn't offer any such functions, Wikipedia babbles about a file-encryption utility and Web searches just reveal a few implementations of Blowfish in different languages. Now Blowfish is also available in PHP via mcrypt, but how does that help with storing passwords? Blowfish is a general purpose cipher, it works two ways. If it could be encrypted, it can be decrypted. Passwords need a one-way hashing function.
What is the explanation?
bcrypt is a hashing algorithm which is scalable with hardware (via a configurable number of rounds). Its slowness and multiple rounds ensures that an attacker must deploy massive funds and hardware to be able to crack your passwords. Add to that per-password salts (bcrypt REQUIRES salts) and you can be sure that an attack is virtually unfeasible without either ludicrous amount of funds or hardware.
bcrypt uses the Eksblowfish algorithm to hash passwords. While the encryption phase of Eksblowfish and Blowfish are exactly the same, the key schedule phase of Eksblowfish ensures that any subsequent state depends on both salt and key (user password), and no state can be precomputed without the knowledge of both. Because of this key difference, bcrypt is a one-way hashing algorithm. You cannot retrieve the plain text password without already knowing the salt, rounds and key (password). [Source]
How to use bcrypt:
Using PHP >= 5.5-DEV
Password hashing functions have now been built directly into PHP >= 5.5. You may now use password_hash() to create a bcrypt hash of any password:
<?php
// Usage 1:
echo password_hash('rasmuslerdorf', PASSWORD_DEFAULT)."\n";
// $2y$10$xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
// For example:
// $2y$10$.vGA1O9wmRjrwAVXD98HNOgsNpDczlqm3Jq7KnEd1rVAGv3Fykk1a
// Usage 2:
$options = [
'cost' => 11
];
echo password_hash('rasmuslerdorf', PASSWORD_BCRYPT, $options)."\n";
// $2y$11$6DP.V0nO7YI3iSki4qog6OQI5eiO6Jnjsqg7vdnb.JgGIsxniOn4C
To verify a user provided password against an existing hash, you may use the password_verify() as such:
<?php
// See the password_hash() example to see where this came from.
$hash = '$2y$07$BCryptRequires22Chrcte/VlQH0piJtjXl.0t1XkA8pw9dMXTpOq';
if (password_verify('rasmuslerdorf', $hash)) {
echo 'Password is valid!';
} else {
echo 'Invalid password.';
}
Using PHP >= 5.3.7, < 5.5-DEV (also RedHat PHP >= 5.3.3)
There is a compatibility library on GitHub created based on the source code of the above functions originally written in C, which provides the same functionality. Once the compatibility library is installed, usage is the same as above (minus the shorthand array notation if you are still on the 5.3.x branch).
Using PHP < 5.3.7 (DEPRECATED)
You can use crypt() function to generate bcrypt hashes of input strings. This class can automatically generate salts and verify existing hashes against an input. If you are using a version of PHP higher or equal to 5.3.7, it is highly recommended you use the built-in function or the compat library. This alternative is provided only for historical purposes.
class Bcrypt{
private $rounds;
public function __construct($rounds = 12) {
if (CRYPT_BLOWFISH != 1) {
throw new Exception("bcrypt not supported in this installation. See http://php.net/crypt");
}
$this->rounds = $rounds;
}
public function hash($input){
$hash = crypt($input, $this->getSalt());
if (strlen($hash) > 13)
return $hash;
return false;
}
public function verify($input, $existingHash){
$hash = crypt($input, $existingHash);
return $hash === $existingHash;
}
private function getSalt(){
$salt = sprintf('$2a$%02d$', $this->rounds);
$bytes = $this->getRandomBytes(16);
$salt .= $this->encodeBytes($bytes);
return $salt;
}
private $randomState;
private function getRandomBytes($count){
$bytes = '';
if (function_exists('openssl_random_pseudo_bytes') &&
(strtoupper(substr(PHP_OS, 0, 3)) !== 'WIN')) { // OpenSSL is slow on Windows
$bytes = openssl_random_pseudo_bytes($count);
}
if ($bytes === '' && is_readable('/dev/urandom') &&
($hRand = #fopen('/dev/urandom', 'rb')) !== FALSE) {
$bytes = fread($hRand, $count);
fclose($hRand);
}
if (strlen($bytes) < $count) {
$bytes = '';
if ($this->randomState === null) {
$this->randomState = microtime();
if (function_exists('getmypid')) {
$this->randomState .= getmypid();
}
}
for ($i = 0; $i < $count; $i += 16) {
$this->randomState = md5(microtime() . $this->randomState);
if (PHP_VERSION >= '5') {
$bytes .= md5($this->randomState, true);
} else {
$bytes .= pack('H*', md5($this->randomState));
}
}
$bytes = substr($bytes, 0, $count);
}
return $bytes;
}
private function encodeBytes($input){
// The following is code from the PHP Password Hashing Framework
$itoa64 = './ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
$output = '';
$i = 0;
do {
$c1 = ord($input[$i++]);
$output .= $itoa64[$c1 >> 2];
$c1 = ($c1 & 0x03) << 4;
if ($i >= 16) {
$output .= $itoa64[$c1];
break;
}
$c2 = ord($input[$i++]);
$c1 |= $c2 >> 4;
$output .= $itoa64[$c1];
$c1 = ($c2 & 0x0f) << 2;
$c2 = ord($input[$i++]);
$c1 |= $c2 >> 6;
$output .= $itoa64[$c1];
$output .= $itoa64[$c2 & 0x3f];
} while (true);
return $output;
}
}
You can use this code like this:
$bcrypt = new Bcrypt(15);
$hash = $bcrypt->hash('password');
$isGood = $bcrypt->verify('password', $hash);
Alternatively, you may also use the Portable PHP Hashing Framework.
So, you want to use bcrypt? Awesome! However, like other areas of cryptography, you shouldn't be doing it yourself. If you need to worry about anything like managing keys, or storing salts or generating random numbers, you're doing it wrong.
The reason is simple: it's so trivially easy to screw up bcrypt. In fact, if you look at almost every piece of code on this page, you'll notice that it's violating at least one of these common problems.
Face It, Cryptography is hard.
Leave it for the experts. Leave it for people whose job it is to maintain these libraries. If you need to make a decision, you're doing it wrong.
Instead, just use a library. Several exist depending on your requirements.
Libraries
Here is a breakdown of some of the more common APIs.
PHP 5.5 API - (Available for 5.3.7+)
Starting in PHP 5.5, a new API for hashing passwords is being introduced. There is also a shim compatibility library maintained (by me) for 5.3.7+. This has the benefit of being a peer-reviewed and simple to use implementation.
function register($username, $password) {
$hash = password_hash($password, PASSWORD_BCRYPT);
save($username, $hash);
}
function login($username, $password) {
$hash = loadHashByUsername($username);
if (password_verify($password, $hash)) {
//login
} else {
// failure
}
}
Really, it's aimed to be extremely simple.
Resources:
Documentation: on PHP.net
Compatibility Library: on GitHub
PHP's RFC: on wiki.php.net
Zend\Crypt\Password\Bcrypt (5.3.2+)
This is another API that's similar to the PHP 5.5 one, and does a similar purpose.
function register($username, $password) {
$bcrypt = new Zend\Crypt\Password\Bcrypt();
$hash = $bcrypt->create($password);
save($user, $hash);
}
function login($username, $password) {
$hash = loadHashByUsername($username);
$bcrypt = new Zend\Crypt\Password\Bcrypt();
if ($bcrypt->verify($password, $hash)) {
//login
} else {
// failure
}
}
Resources:
Documentation: on Zend
Blog Post: Password Hashing With Zend Crypt
PasswordLib
This is a slightly different approach to password hashing. Rather than simply supporting bcrypt, PasswordLib supports a large number of hashing algorithms. It's mainly useful in contexts where you need to support compatibility with legacy and disparate systems that may be outside of your control. It supports a large number of hashing algorithms. And is supported 5.3.2+
function register($username, $password) {
$lib = new PasswordLib\PasswordLib();
$hash = $lib->createPasswordHash($password, '$2y$', array('cost' => 12));
save($user, $hash);
}
function login($username, $password) {
$hash = loadHashByUsername($username);
$lib = new PasswordLib\PasswordLib();
if ($lib->verifyPasswordHash($password, $hash)) {
//login
} else {
// failure
}
}
References:
Source Code / Documentation: GitHub
PHPASS
This is a layer that does support bcrypt, but also supports a fairly strong algorithm that's useful if you do not have access to PHP >= 5.3.2... It actually supports PHP 3.0+ (although not with bcrypt).
function register($username, $password) {
$phpass = new PasswordHash(12, false);
$hash = $phpass->HashPassword($password);
save($user, $hash);
}
function login($username, $password) {
$hash = loadHashByUsername($username);
$phpass = new PasswordHash(12, false);
if ($phpass->CheckPassword($password, $hash)) {
//login
} else {
// failure
}
}
Resources
Code: cvsweb
Project Site: on OpenWall
A review of the < 5.3.0 algorithm: on StackOverflow
Note: Don't use the PHPASS alternatives that are not hosted on openwall, they are different projects!!!
About BCrypt
If you notice, every one of these libraries returns a single string. That's because of how BCrypt works internally. And there are a TON of answers about that. Here are a selection that I've written, that I won't copy/paste here, but link to:
Fundamental Difference Between Hashing And Encryption Algorithms - Explaining the terminology and some basic information about them.
About reversing hashes without rainbow tables - Basically why we should use bcrypt in the first place...
Storing bcrypt Hashes - basically why is the salt and algorithm included in the hash result.
How to update the cost of bcrypt hashes - basically how to choose and then maintain the cost of the bcrypt hash.
How to hash long passwords with bcrypt - explaining the 72 character password limit of bcrypt.
How bcrypt uses salts
Best practices of salting and peppering passwords - Basically, don't use a "pepper"
Migrating old md5 passwords to bcrypt
Wrap Up
There are many different choices. Which you choose is up to you. However, I would HIGHLY recommend that you use one of the above libraries for handling this for you.
Again, if you're using crypt() directly, you're probably doing something wrong. If your code is using hash() (or md5() or sha1()) directly, you're almost definitely doing something wrong.
Just use a library...
You'll get a lot of information in Enough With The Rainbow Tables: What You Need To Know About Secure Password Schemes or Portable PHP password hashing framework.
The goal is to hash the password with something slow, so someone getting your password database will die trying to brute force it (a 10 ms delay to check a password is nothing for you, a lot for someone trying to brute force it). Bcrypt is slow and can be used with a parameter to choose how slow it is.
You can create a one-way hash with bcrypt using PHP's crypt() function and passing in an appropriate Blowfish salt. The most important of the whole equation is that A) the algorithm hasn't been compromised and B) you properly salt each password. Don't use an application-wide salt; that opens up your entire application to attack from a single set of Rainbow tables.
PHP - Crypt Function
Edit: 2013.01.15 - If your server will support it, use martinstoeckli's solution instead.
Everyone wants to make this more complicated than it is. The crypt() function does most of the work.
function blowfishCrypt($password,$cost)
{
$chars='./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
$salt=sprintf('$2y$%02d$',$cost);
//For PHP < PHP 5.3.7 use this instead
// $salt=sprintf('$2a$%02d$',$cost);
//Create a 22 character salt -edit- 2013.01.15 - replaced rand with mt_rand
mt_srand();
for($i=0;$i<22;$i++) $salt.=$chars[mt_rand(0,63)];
return crypt($password,$salt);
}
Example:
$hash=blowfishCrypt('password',10); //This creates the hash
$hash=blowfishCrypt('password',12); //This creates a more secure hash
if(crypt('password',$hash)==$hash){ /*ok*/ } //This checks a password
I know it should be obvious, but please don't use 'password' as your password.
Version 5.5 of PHP will have built-in support for BCrypt, the functions password_hash() and password_verify(). Actually these are just wrappers around the function crypt(), and shall make it easier to use it correctly. It takes care of the generation of a safe random salt, and provides good default values.
The easiest way to use this functions will be:
$hashToStoreInDb = password_hash($password, PASSWORD_BCRYPT);
$isPasswordCorrect = password_verify($password, $existingHashFromDb);
This code will hash the password with BCrypt (algorithm 2y), generates a random salt from the OS random source, and uses the default cost parameter (at the moment this is 10). The second line checks, if the user entered password matches an already stored hash-value.
Should you want to change the cost parameter, you can do it like this, increasing the cost parameter by 1, doubles the needed time to calculate the hash value:
$hash = password_hash($password, PASSWORD_BCRYPT, array("cost" => 11));
In contrast to the "cost" parameter, it is best to omit the "salt" parameter, because the function already does its best to create a cryptographically safe salt.
For PHP version 5.3.7 and later, there exists a compatibility pack, from the same author that made the password_hash() function. For PHP versions before 5.3.7 there is no support for crypt() with 2y, the unicode safe BCrypt algorithm. One could replace it instead with 2a, which is the best alternative for earlier PHP versions.
Current thinking: hashes should be the slowest available, not the fastest possible. This suppresses rainbow table attacks.
Also related, but precautionary: An attacker should never have unlimited access to your login screen. To prevent that: Set up an IP address tracking table that records every hit along with the URI. If more than 5 attempts to login come from the same IP address in any five minute period, block with explanation. A secondary approach is to have a two-tiered password scheme, like banks do. Putting a lock-out for failures on the second pass boosts security.
Summary: slow down the attacker by using time-consuming hash functions. Also, block on too many accesses to your login, and add a second password tier.
Here's an updated answer to this old question!
The right way to hash passwords in PHP since 5.5 is with password_hash(), and the right way to verify them is with password_verify(), and this is still true in PHP 8.0. These functions use bcrypt hashes by default, but other stronger algorithms have been added. You can alter the work factor (effectively how "strong" the encryption is) via the password_hash parameters.
However, while it's still plenty strong enough, bcrypt is no longer considered state-of-the-art; a better set of password hash algorithms has arrived called Argon2, with Argon2i, Argon2d, and Argon2id variants. The difference between them (as described here):
Argon2 has one primary variant: Argon2id, and two supplementary variants: Argon2d and Argon2i. Argon2d uses data-depending memory access, which makes it suitable for cryptocurrencies and proof-of-work applications with no threats from side-channel timing attacks. Argon2i uses data-independent memory access, which is preferred for password hashing and password-based key derivation. Argon2id works as Argon2i for the first half of the first iteration over the memory, and as Argon2d for the rest, thus providing both side-channel attack protection and brute-force cost savings due to time-memory tradeoffs.
Argon2i support was added in PHP 7.2, and you request it like this:
$hash = password_hash('mypassword', PASSWORD_ARGON2I);
and Argon2id support was added in PHP 7.3:
$hash = password_hash('mypassword', PASSWORD_ARGON2ID);
No changes are required for verifying passwords since the resulting hash string contains information about what algorithm, salt, and work factors were used when it was created.
Quite separately (and somewhat redundantly), libsodium (added in PHP 7.2) also provides Argon2 hashing via the sodium_crypto_pwhash_str () and sodium_crypto_pwhash_str_verify() functions, which work much the same way as the PHP built-ins. One possible reason for using these is that PHP may sometimes be compiled without libargon2, which makes the Argon2 algorithms unavailable to the password_hash function; PHP 7.2 and higher should always have libsodium enabled, but it may not - but at least there are two ways you can get at that algorithm. Here's how you can create an Argon2id hash with libsodium (even in PHP 7.2, which otherwise lacks Argon2id support)):
$hash = sodium_crypto_pwhash_str(
'mypassword',
SODIUM_CRYPTO_PWHASH_OPSLIMIT_INTERACTIVE,
SODIUM_CRYPTO_PWHASH_MEMLIMIT_INTERACTIVE
);
Note that it doesn't allow you to specify a salt manually; this is part of libsodium's ethos – don't allow users to set params to values that might compromise security – for example there is nothing preventing you from passing an empty salt string to PHP's password_hash function; libsodium doesn't let you do anything so silly!
For OAuth 2 passwords:
$bcrypt = new \Zend\Crypt\Password\Bcrypt;
$bcrypt->create("youpasswordhere", 10)
As we all know storing password in clear text in database is not secure.
the bcrypt is a hashing password technique.It is used to built password security. One of the amazing function of bcrypt is it save us from hackers it is used to protect the password from hacking attacks because the password is stored in bcrypted form.
The password_hash() function is used to create a new password hash. It uses a strong & robust hashing algorithm. The password_hash() function is very much compatible with the crypt() function. Therefore, password hashes created by crypt() may be used with password_hash() and vice-versa. The functions password_verify() and password_hash() just the wrappers around the function crypt(), and they make it much easier to use it accurately.
SYNTAX
string password_hash($password, $algo, $options)
The following algorithms are currently supported by password_hash() function:
PASSWORD_DEFAULT
PASSWORD_BCRYPT
PASSWORD_ARGON2I
PASSWORD_ARGON2ID
Parameters: This function accepts three parameters as mentioned above and described below:
$password: It stores the password of the user.
$algo: It is the password algorithm constant that is used continuously while denoting the algorithm which is to be used when the hashing of password takes place.
$options: It is an associative array, which contains the options. If this is removed and doesn’t include, a random salt is going to be used, and the utilization of a default cost will happen.
Return Value: It returns the hashed password on success or False on failure.
Example:
Input:
echo password_hash("GFG#123", PASSWORD_DEFAULT);
Output:
$2y$10$.vGA19Jh8YrwSJFDodbfoHJIOFH)DfhuofGv3Fykk1a
Below programs illustrate the password_hash() function in PHP:
<?php echo password_hash("GFG#123", PASSWORD_DEFAULT); ?>
OUTPUT
$2y$10$Z166W1fBdsLcXPVQVfPw/uRq1ueWMA6sLt9bmdUFz9AmOGLdM393G
The password_hash() function in PHP is a built-in function, used to create a new password hash with different algorithms and options. The function uses a strong hashing algorithm.
The function take 2 mandatory parameters: $password and $algorithm, and 1 optional parameter $options.
$strongPassword = password_hash( $password, $algorithm, $options );
Algorithms allowed right now for password_hash() are:
PASSWORD_DEFAULT
PASSWORD_BCRYPT
PASSWORD_ARGON2I
PASSWORD_ARGON2ID
Example:
echo password_hash("abcDEF", PASSWORD_DEFAULT);
Answer:
$2y$10$KwKceUaG84WInAif5ehdZOkE4kHPWTLp0ZK5a5OU2EbtdwQ9YIcGy
Example:
echo password_hash("abcDEF", PASSWORD_BCRYPT);
Answer:
$2y$10$SNly5bFzB/R6OVbBMq1bj.yiOZdsk6Mwgqi4BLR2sqdCvMyv/AyL2
To use the BCRYPT, set option cost=12 in an $options, also change first parameter $password to some strong password like "wgt167yuWBGY##1987__".
Example:
echo password_hash("wgt167yuWBGY##1987__", PASSWORD_BCRYPT, ['cost' => 12]);
Answer:
$2y$12$TjSggXiFSidD63E.QP8PJOds2texJfsk/82VaNU8XRZ/niZhzkJ6S
I modified my old post. I tried the crypt() function and now trying to work with password_hash() and password_verify() to verify the encrypted password coming from database but on each call, password_hash() function retuns a different encrypted string and password_verify() cannot match it.
This is how I am doing this.
//please ignore the syntax error if any
$data = '11';
$dbpass = password_hash($data, PASSWORD_BCRYPT);
echo $dbpass; // displays the random strings on each page refresh.
Once password is saved into database does not get match during the login process. Below is my actual function.
private function process_data($password){
$password = __STR.$password.__STR;
return password_hash($password, PASSWORD_BCRYPT);
}
private function processed($login_password, $dbpassword){
$login_password = __STR.$login_password.__STR;
return password_verify($login_password, $dbpassword);
}
On each function call for creating a hashed string for password, the function returns the different string next time.
Ok, Let's go through this one by one.
First, it's hashing, not encryption. Encryption is two-way, hashing is one way. We want to hash. We never want to encrypt. Yes, terminology matters. Please use the correct terminology.
Next, each call to password_hash is supposed to return a different hash. That's because it's generating a strong random salt. This is how it was designed, and how you really should be using it.
Further, DO NOT do the "pepper" thing of adding __STR before and after the password. You're doing nothing but potentially weakening the users password (which is not good). If you want more information around why that's a bad idea: Read This Answer.
Continuing, I would highly recommend that you do not use crypt directly. It is actually surprisingly easy to screw up and generate extremely weak hashes. This is why the password_* api was designed. crypt is a low level library, you want to use a high level library in your code. For more information on ways to screw up bcrypt, check out my blog: Seven Ways To Screw Up Bcrypt.
The Password API was designed to be a simple, one-stop shop. If it's not working for you check the following things:
Are you using PHP >= 5.5.0? Or are you using PHP >= 5.3.7 with password_compat?
Is your database column wide enough?
It needs to be at least 60 characters long.
Are you checking that the result of the function is a string, and not bool(false)?
If there is an internal error, it will return a non-string from password_hash.
Are you getting any errors?
Have you turned on error_reporting to its maximum setting (I recommend -1 to catch everything) and checked that the code isn't throwing any errors?
Are you sure you are using it correctly?
function saveUser($username, $password) {
$hash = password_hash($password, PASSWORD_BCRYPT);
// save $username and $hash to db
}
function login($username, $password) {
// fetch $hash from db
return password_verify($password, $hash);
}
Note that each one should be called only once.
Are you using PHP < 5.3.7 with password_compat? If so, this is your problem. You are using the compatability library on an unsupported version of PHP. You may get it to work (certain RedHat distributions have backported the necessary fixes), but you are using an unsupported version. Please upgrade to a reasonable release.
If all else fails, please try running this code and reporting back the output:
$hash = '$2y$04$usesomesillystringfore7hnbRJHxXVLeakoG8K30oukPsA.ztMG';
$test = crypt("password", $hash);
$pass = $test == $hash;
echo "Test for functionality of compat library: " . ($pass ? "Pass" : "Fail");
echo "\n";
If that returns Fail, you are running an unsupported version of PHP and should upgrade. If it returns pass, than the error is somewhere in your logic (the library is functioning fine).
The best way to store passwords is to use PHP's function password_hash(). It automatically generates a cryptographically safe salt for each password and includes it in the resulting 60-character string. You won't have to worry about the salt at all!
// Hash a new password for storing in the database.
// The function automatically generates a cryptographically safe salt.
$hashToStoreInDb = password_hash($password, PASSWORD_BCRYPT);
// Check if the hash of the entered login password, matches the stored hash.
// The salt and the cost factor will be extracted from $existingHashFromDb.
$isPasswordCorrect = password_verify($password, $existingHashFromDb);
Your own scheme is very weak, first you are using MD5 which is ways too fast for generating password hashes, then you use a static salt, which defeats the purpose of a salt. Maybe you want to have a look at my tutorial about safely storing passwords.
Edit to answer updated question:
It is not necessary to add the __STR to the password (if you want to add a pepper there are better ways), but your example functions should actually work. The returned value of password_hash() will be different each time because of the random salt. This is correct, the function password_verify() is able to extract this salt for the verification. In your case the database field is probably the problem. Make sure it can hold a 60 character string.
I'm trying to generate salt using Mcrypt's mcrypt_create_iv(), but it doesn't seems to work and I'm getting errors.
Here is my code:
<?php
$salt= substr(mcrypt_create_iv(16, MCRYPT_DEV_URANDOM))(mt_rand()),0,22);
echo $salt;
?>
$salt = substr( mcrypt_create_iv(16, MCRYPT_DEV_URANDOM), mt_rand( 0, 22 ) );
you have some syntax errors
This cannot work, you use mcrypt_create_iv() to get random bytes, but those cannot be used for hashing with BCrypt. The problem is, that mcrypt_create_iv returns binary data, while BCrypt expects a salt with characters of a given alphabet. You would have to encode your salt to this alphabet: ./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz. The function mt_rand() is of no use here.
PHP 5.5 will have it's own functions password_hash() and password_verify() ready, to simplify generating BCrypt password hashes. I strongly recommend to use this excellent api, or it's compatibility pack for earlier PHP versions. The usage is very straightforward:
// Hash a new password for storing in the database.
// The function automatically generates a cryptographically safe salt.
$hashToStoreInDb = password_hash($password, PASSWORD_BCRYPT);
// Check if the hash of the entered login password, matches the stored hash.
// The salt and the cost factor will be extracted from $existingHashFromDb.
$isPasswordCorrect = password_verify($password, $existingHashFromDb);
This is my first time using the crypt() function in PHP, and I can't figure out why it isn't working. My code is based on this article: http://www.techrepublic.com/blog/australia/securing-passwords-with-blowfish/1274
function blowfishHash ($pw) {
//generate random salt
$salt = "$2y$10$";
for ($i = 0; $i < 22; $i++) {
$salt .= substr("./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789", mt_rand(0, 63), 1);
}
$hash = crypt($pw, $salt);
//printout to file
$file = fopen("debug.txt", "w+");
fwrite($file, "\n\n\n".$pw);
fwrite($file, "\n\n\n".$salt);
fwrite($file, "\n\n\n".$hash);
fclose($file);
return $hash;
}
I called the function with the sample password "password".
The resultant salt was: $2y$10$NzRQNjTRfP4jXKvb4TCO.G
But the password was "$2mV0NZp92R3g" – which seems far too short.
Could someone please help me figure out what I'm doing wrong?
As you stated in your comment, you are using PHP 5.2.x.
The Blowfish implementation is only available in PHP >= 5.3.x. If for any reason it is not possible to install a newer PHP version, you could check here on more information on how to make Blowfish work with older PHP versions.
Since crypt in PHP 5.2 doesn't support CRYPT_BLOWFISH, it is instead defaulting to interpreting the salt as a CRYPT_DES style salt. Notice that the output starts with "$2", which is the two character salt that CRYPT_DES chose from the salt input and prepended to the hash, and the output length matches the exact CRYPT_DES output length.
Interestingly, you can achieve the same result in later PHP versions with CRYPT_BLOWFISH support by simply truncating the salt to two characters. Ie:
crypt('password', '$2y$10$NzRQNjTRfP4jXKvb4TCO.G') /* in PHP 5.2 */
==
crypt('password', '$2') /* in PHP 5.4 */
In theory, this might come in handy for backwards-compatibility if a CRYPT_BLOWFISH style salt was used in error on PHP 5.2.
This actually caused me a bit of confusion recently because the "$" character isn't valid salt input for CRYPT_DES as per the PHP crypt documentation, which says:
Standard DES-based hash with a two character salt from the alphabet "./0-9A-Za-z". Using invalid characters in the salt will cause crypt() to fail.
But here the "$" character clearly seems to be accepted by crypt() in both v5.2 and v5.4.
It would be both clearer and safer if crypt actually returned a failure like the documentation says it's supposed to, rather than accepting the "$" and defaulting to CRYPT_DES.
here is my blowfish encryption function ....
<?php
function bcrypt($input, $salt=null, $rounds=12) {
if($rounds < 4 || $rounds > 31) $rounds = 12;
if(is_null($salt)) $salt = sprintf('$2a$%02d$', $rounds).substr(str_replace('+', '.', base64_encode(pack('N4', mt_rand(), mt_rand(), mt_rand(), mt_rand()))), 0, 22);
return crypt($input, $salt);
}
$hash = bcrypt('password');
if($hash = bcrypt('password', $hash)) {
// password ok
}
?>
Initially only blowfish hashing with a salt starting with $2a$ was supported.
$2x$ and $2y$ Blowfish modes were added in PHP 5.3.7 to deal with potential high-bit attacks.
Your PHP 5.2.17 does not support $2y$ Blowfish mode.
This why your code is not working.
This question already has answers here:
How to use PHP's password_hash to hash and verify passwords
(5 answers)
Closed 9 months ago.
Every now and then I hear the advice "Use bcrypt for storing passwords in PHP, bcrypt rules".
But what is bcrypt? PHP doesn't offer any such functions, Wikipedia babbles about a file-encryption utility and Web searches just reveal a few implementations of Blowfish in different languages. Now Blowfish is also available in PHP via mcrypt, but how does that help with storing passwords? Blowfish is a general purpose cipher, it works two ways. If it could be encrypted, it can be decrypted. Passwords need a one-way hashing function.
What is the explanation?
bcrypt is a hashing algorithm which is scalable with hardware (via a configurable number of rounds). Its slowness and multiple rounds ensures that an attacker must deploy massive funds and hardware to be able to crack your passwords. Add to that per-password salts (bcrypt REQUIRES salts) and you can be sure that an attack is virtually unfeasible without either ludicrous amount of funds or hardware.
bcrypt uses the Eksblowfish algorithm to hash passwords. While the encryption phase of Eksblowfish and Blowfish are exactly the same, the key schedule phase of Eksblowfish ensures that any subsequent state depends on both salt and key (user password), and no state can be precomputed without the knowledge of both. Because of this key difference, bcrypt is a one-way hashing algorithm. You cannot retrieve the plain text password without already knowing the salt, rounds and key (password). [Source]
How to use bcrypt:
Using PHP >= 5.5-DEV
Password hashing functions have now been built directly into PHP >= 5.5. You may now use password_hash() to create a bcrypt hash of any password:
<?php
// Usage 1:
echo password_hash('rasmuslerdorf', PASSWORD_DEFAULT)."\n";
// $2y$10$xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
// For example:
// $2y$10$.vGA1O9wmRjrwAVXD98HNOgsNpDczlqm3Jq7KnEd1rVAGv3Fykk1a
// Usage 2:
$options = [
'cost' => 11
];
echo password_hash('rasmuslerdorf', PASSWORD_BCRYPT, $options)."\n";
// $2y$11$6DP.V0nO7YI3iSki4qog6OQI5eiO6Jnjsqg7vdnb.JgGIsxniOn4C
To verify a user provided password against an existing hash, you may use the password_verify() as such:
<?php
// See the password_hash() example to see where this came from.
$hash = '$2y$07$BCryptRequires22Chrcte/VlQH0piJtjXl.0t1XkA8pw9dMXTpOq';
if (password_verify('rasmuslerdorf', $hash)) {
echo 'Password is valid!';
} else {
echo 'Invalid password.';
}
Using PHP >= 5.3.7, < 5.5-DEV (also RedHat PHP >= 5.3.3)
There is a compatibility library on GitHub created based on the source code of the above functions originally written in C, which provides the same functionality. Once the compatibility library is installed, usage is the same as above (minus the shorthand array notation if you are still on the 5.3.x branch).
Using PHP < 5.3.7 (DEPRECATED)
You can use crypt() function to generate bcrypt hashes of input strings. This class can automatically generate salts and verify existing hashes against an input. If you are using a version of PHP higher or equal to 5.3.7, it is highly recommended you use the built-in function or the compat library. This alternative is provided only for historical purposes.
class Bcrypt{
private $rounds;
public function __construct($rounds = 12) {
if (CRYPT_BLOWFISH != 1) {
throw new Exception("bcrypt not supported in this installation. See http://php.net/crypt");
}
$this->rounds = $rounds;
}
public function hash($input){
$hash = crypt($input, $this->getSalt());
if (strlen($hash) > 13)
return $hash;
return false;
}
public function verify($input, $existingHash){
$hash = crypt($input, $existingHash);
return $hash === $existingHash;
}
private function getSalt(){
$salt = sprintf('$2a$%02d$', $this->rounds);
$bytes = $this->getRandomBytes(16);
$salt .= $this->encodeBytes($bytes);
return $salt;
}
private $randomState;
private function getRandomBytes($count){
$bytes = '';
if (function_exists('openssl_random_pseudo_bytes') &&
(strtoupper(substr(PHP_OS, 0, 3)) !== 'WIN')) { // OpenSSL is slow on Windows
$bytes = openssl_random_pseudo_bytes($count);
}
if ($bytes === '' && is_readable('/dev/urandom') &&
($hRand = #fopen('/dev/urandom', 'rb')) !== FALSE) {
$bytes = fread($hRand, $count);
fclose($hRand);
}
if (strlen($bytes) < $count) {
$bytes = '';
if ($this->randomState === null) {
$this->randomState = microtime();
if (function_exists('getmypid')) {
$this->randomState .= getmypid();
}
}
for ($i = 0; $i < $count; $i += 16) {
$this->randomState = md5(microtime() . $this->randomState);
if (PHP_VERSION >= '5') {
$bytes .= md5($this->randomState, true);
} else {
$bytes .= pack('H*', md5($this->randomState));
}
}
$bytes = substr($bytes, 0, $count);
}
return $bytes;
}
private function encodeBytes($input){
// The following is code from the PHP Password Hashing Framework
$itoa64 = './ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
$output = '';
$i = 0;
do {
$c1 = ord($input[$i++]);
$output .= $itoa64[$c1 >> 2];
$c1 = ($c1 & 0x03) << 4;
if ($i >= 16) {
$output .= $itoa64[$c1];
break;
}
$c2 = ord($input[$i++]);
$c1 |= $c2 >> 4;
$output .= $itoa64[$c1];
$c1 = ($c2 & 0x0f) << 2;
$c2 = ord($input[$i++]);
$c1 |= $c2 >> 6;
$output .= $itoa64[$c1];
$output .= $itoa64[$c2 & 0x3f];
} while (true);
return $output;
}
}
You can use this code like this:
$bcrypt = new Bcrypt(15);
$hash = $bcrypt->hash('password');
$isGood = $bcrypt->verify('password', $hash);
Alternatively, you may also use the Portable PHP Hashing Framework.
So, you want to use bcrypt? Awesome! However, like other areas of cryptography, you shouldn't be doing it yourself. If you need to worry about anything like managing keys, or storing salts or generating random numbers, you're doing it wrong.
The reason is simple: it's so trivially easy to screw up bcrypt. In fact, if you look at almost every piece of code on this page, you'll notice that it's violating at least one of these common problems.
Face It, Cryptography is hard.
Leave it for the experts. Leave it for people whose job it is to maintain these libraries. If you need to make a decision, you're doing it wrong.
Instead, just use a library. Several exist depending on your requirements.
Libraries
Here is a breakdown of some of the more common APIs.
PHP 5.5 API - (Available for 5.3.7+)
Starting in PHP 5.5, a new API for hashing passwords is being introduced. There is also a shim compatibility library maintained (by me) for 5.3.7+. This has the benefit of being a peer-reviewed and simple to use implementation.
function register($username, $password) {
$hash = password_hash($password, PASSWORD_BCRYPT);
save($username, $hash);
}
function login($username, $password) {
$hash = loadHashByUsername($username);
if (password_verify($password, $hash)) {
//login
} else {
// failure
}
}
Really, it's aimed to be extremely simple.
Resources:
Documentation: on PHP.net
Compatibility Library: on GitHub
PHP's RFC: on wiki.php.net
Zend\Crypt\Password\Bcrypt (5.3.2+)
This is another API that's similar to the PHP 5.5 one, and does a similar purpose.
function register($username, $password) {
$bcrypt = new Zend\Crypt\Password\Bcrypt();
$hash = $bcrypt->create($password);
save($user, $hash);
}
function login($username, $password) {
$hash = loadHashByUsername($username);
$bcrypt = new Zend\Crypt\Password\Bcrypt();
if ($bcrypt->verify($password, $hash)) {
//login
} else {
// failure
}
}
Resources:
Documentation: on Zend
Blog Post: Password Hashing With Zend Crypt
PasswordLib
This is a slightly different approach to password hashing. Rather than simply supporting bcrypt, PasswordLib supports a large number of hashing algorithms. It's mainly useful in contexts where you need to support compatibility with legacy and disparate systems that may be outside of your control. It supports a large number of hashing algorithms. And is supported 5.3.2+
function register($username, $password) {
$lib = new PasswordLib\PasswordLib();
$hash = $lib->createPasswordHash($password, '$2y$', array('cost' => 12));
save($user, $hash);
}
function login($username, $password) {
$hash = loadHashByUsername($username);
$lib = new PasswordLib\PasswordLib();
if ($lib->verifyPasswordHash($password, $hash)) {
//login
} else {
// failure
}
}
References:
Source Code / Documentation: GitHub
PHPASS
This is a layer that does support bcrypt, but also supports a fairly strong algorithm that's useful if you do not have access to PHP >= 5.3.2... It actually supports PHP 3.0+ (although not with bcrypt).
function register($username, $password) {
$phpass = new PasswordHash(12, false);
$hash = $phpass->HashPassword($password);
save($user, $hash);
}
function login($username, $password) {
$hash = loadHashByUsername($username);
$phpass = new PasswordHash(12, false);
if ($phpass->CheckPassword($password, $hash)) {
//login
} else {
// failure
}
}
Resources
Code: cvsweb
Project Site: on OpenWall
A review of the < 5.3.0 algorithm: on StackOverflow
Note: Don't use the PHPASS alternatives that are not hosted on openwall, they are different projects!!!
About BCrypt
If you notice, every one of these libraries returns a single string. That's because of how BCrypt works internally. And there are a TON of answers about that. Here are a selection that I've written, that I won't copy/paste here, but link to:
Fundamental Difference Between Hashing And Encryption Algorithms - Explaining the terminology and some basic information about them.
About reversing hashes without rainbow tables - Basically why we should use bcrypt in the first place...
Storing bcrypt Hashes - basically why is the salt and algorithm included in the hash result.
How to update the cost of bcrypt hashes - basically how to choose and then maintain the cost of the bcrypt hash.
How to hash long passwords with bcrypt - explaining the 72 character password limit of bcrypt.
How bcrypt uses salts
Best practices of salting and peppering passwords - Basically, don't use a "pepper"
Migrating old md5 passwords to bcrypt
Wrap Up
There are many different choices. Which you choose is up to you. However, I would HIGHLY recommend that you use one of the above libraries for handling this for you.
Again, if you're using crypt() directly, you're probably doing something wrong. If your code is using hash() (or md5() or sha1()) directly, you're almost definitely doing something wrong.
Just use a library...
You'll get a lot of information in Enough With The Rainbow Tables: What You Need To Know About Secure Password Schemes or Portable PHP password hashing framework.
The goal is to hash the password with something slow, so someone getting your password database will die trying to brute force it (a 10 ms delay to check a password is nothing for you, a lot for someone trying to brute force it). Bcrypt is slow and can be used with a parameter to choose how slow it is.
You can create a one-way hash with bcrypt using PHP's crypt() function and passing in an appropriate Blowfish salt. The most important of the whole equation is that A) the algorithm hasn't been compromised and B) you properly salt each password. Don't use an application-wide salt; that opens up your entire application to attack from a single set of Rainbow tables.
PHP - Crypt Function
Edit: 2013.01.15 - If your server will support it, use martinstoeckli's solution instead.
Everyone wants to make this more complicated than it is. The crypt() function does most of the work.
function blowfishCrypt($password,$cost)
{
$chars='./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
$salt=sprintf('$2y$%02d$',$cost);
//For PHP < PHP 5.3.7 use this instead
// $salt=sprintf('$2a$%02d$',$cost);
//Create a 22 character salt -edit- 2013.01.15 - replaced rand with mt_rand
mt_srand();
for($i=0;$i<22;$i++) $salt.=$chars[mt_rand(0,63)];
return crypt($password,$salt);
}
Example:
$hash=blowfishCrypt('password',10); //This creates the hash
$hash=blowfishCrypt('password',12); //This creates a more secure hash
if(crypt('password',$hash)==$hash){ /*ok*/ } //This checks a password
I know it should be obvious, but please don't use 'password' as your password.
Version 5.5 of PHP will have built-in support for BCrypt, the functions password_hash() and password_verify(). Actually these are just wrappers around the function crypt(), and shall make it easier to use it correctly. It takes care of the generation of a safe random salt, and provides good default values.
The easiest way to use this functions will be:
$hashToStoreInDb = password_hash($password, PASSWORD_BCRYPT);
$isPasswordCorrect = password_verify($password, $existingHashFromDb);
This code will hash the password with BCrypt (algorithm 2y), generates a random salt from the OS random source, and uses the default cost parameter (at the moment this is 10). The second line checks, if the user entered password matches an already stored hash-value.
Should you want to change the cost parameter, you can do it like this, increasing the cost parameter by 1, doubles the needed time to calculate the hash value:
$hash = password_hash($password, PASSWORD_BCRYPT, array("cost" => 11));
In contrast to the "cost" parameter, it is best to omit the "salt" parameter, because the function already does its best to create a cryptographically safe salt.
For PHP version 5.3.7 and later, there exists a compatibility pack, from the same author that made the password_hash() function. For PHP versions before 5.3.7 there is no support for crypt() with 2y, the unicode safe BCrypt algorithm. One could replace it instead with 2a, which is the best alternative for earlier PHP versions.
Current thinking: hashes should be the slowest available, not the fastest possible. This suppresses rainbow table attacks.
Also related, but precautionary: An attacker should never have unlimited access to your login screen. To prevent that: Set up an IP address tracking table that records every hit along with the URI. If more than 5 attempts to login come from the same IP address in any five minute period, block with explanation. A secondary approach is to have a two-tiered password scheme, like banks do. Putting a lock-out for failures on the second pass boosts security.
Summary: slow down the attacker by using time-consuming hash functions. Also, block on too many accesses to your login, and add a second password tier.
Here's an updated answer to this old question!
The right way to hash passwords in PHP since 5.5 is with password_hash(), and the right way to verify them is with password_verify(), and this is still true in PHP 8.0. These functions use bcrypt hashes by default, but other stronger algorithms have been added. You can alter the work factor (effectively how "strong" the encryption is) via the password_hash parameters.
However, while it's still plenty strong enough, bcrypt is no longer considered state-of-the-art; a better set of password hash algorithms has arrived called Argon2, with Argon2i, Argon2d, and Argon2id variants. The difference between them (as described here):
Argon2 has one primary variant: Argon2id, and two supplementary variants: Argon2d and Argon2i. Argon2d uses data-depending memory access, which makes it suitable for cryptocurrencies and proof-of-work applications with no threats from side-channel timing attacks. Argon2i uses data-independent memory access, which is preferred for password hashing and password-based key derivation. Argon2id works as Argon2i for the first half of the first iteration over the memory, and as Argon2d for the rest, thus providing both side-channel attack protection and brute-force cost savings due to time-memory tradeoffs.
Argon2i support was added in PHP 7.2, and you request it like this:
$hash = password_hash('mypassword', PASSWORD_ARGON2I);
and Argon2id support was added in PHP 7.3:
$hash = password_hash('mypassword', PASSWORD_ARGON2ID);
No changes are required for verifying passwords since the resulting hash string contains information about what algorithm, salt, and work factors were used when it was created.
Quite separately (and somewhat redundantly), libsodium (added in PHP 7.2) also provides Argon2 hashing via the sodium_crypto_pwhash_str () and sodium_crypto_pwhash_str_verify() functions, which work much the same way as the PHP built-ins. One possible reason for using these is that PHP may sometimes be compiled without libargon2, which makes the Argon2 algorithms unavailable to the password_hash function; PHP 7.2 and higher should always have libsodium enabled, but it may not - but at least there are two ways you can get at that algorithm. Here's how you can create an Argon2id hash with libsodium (even in PHP 7.2, which otherwise lacks Argon2id support)):
$hash = sodium_crypto_pwhash_str(
'mypassword',
SODIUM_CRYPTO_PWHASH_OPSLIMIT_INTERACTIVE,
SODIUM_CRYPTO_PWHASH_MEMLIMIT_INTERACTIVE
);
Note that it doesn't allow you to specify a salt manually; this is part of libsodium's ethos – don't allow users to set params to values that might compromise security – for example there is nothing preventing you from passing an empty salt string to PHP's password_hash function; libsodium doesn't let you do anything so silly!
For OAuth 2 passwords:
$bcrypt = new \Zend\Crypt\Password\Bcrypt;
$bcrypt->create("youpasswordhere", 10)
As we all know storing password in clear text in database is not secure.
the bcrypt is a hashing password technique.It is used to built password security. One of the amazing function of bcrypt is it save us from hackers it is used to protect the password from hacking attacks because the password is stored in bcrypted form.
The password_hash() function is used to create a new password hash. It uses a strong & robust hashing algorithm. The password_hash() function is very much compatible with the crypt() function. Therefore, password hashes created by crypt() may be used with password_hash() and vice-versa. The functions password_verify() and password_hash() just the wrappers around the function crypt(), and they make it much easier to use it accurately.
SYNTAX
string password_hash($password, $algo, $options)
The following algorithms are currently supported by password_hash() function:
PASSWORD_DEFAULT
PASSWORD_BCRYPT
PASSWORD_ARGON2I
PASSWORD_ARGON2ID
Parameters: This function accepts three parameters as mentioned above and described below:
$password: It stores the password of the user.
$algo: It is the password algorithm constant that is used continuously while denoting the algorithm which is to be used when the hashing of password takes place.
$options: It is an associative array, which contains the options. If this is removed and doesn’t include, a random salt is going to be used, and the utilization of a default cost will happen.
Return Value: It returns the hashed password on success or False on failure.
Example:
Input:
echo password_hash("GFG#123", PASSWORD_DEFAULT);
Output:
$2y$10$.vGA19Jh8YrwSJFDodbfoHJIOFH)DfhuofGv3Fykk1a
Below programs illustrate the password_hash() function in PHP:
<?php echo password_hash("GFG#123", PASSWORD_DEFAULT); ?>
OUTPUT
$2y$10$Z166W1fBdsLcXPVQVfPw/uRq1ueWMA6sLt9bmdUFz9AmOGLdM393G
The password_hash() function in PHP is a built-in function, used to create a new password hash with different algorithms and options. The function uses a strong hashing algorithm.
The function take 2 mandatory parameters: $password and $algorithm, and 1 optional parameter $options.
$strongPassword = password_hash( $password, $algorithm, $options );
Algorithms allowed right now for password_hash() are:
PASSWORD_DEFAULT
PASSWORD_BCRYPT
PASSWORD_ARGON2I
PASSWORD_ARGON2ID
Example:
echo password_hash("abcDEF", PASSWORD_DEFAULT);
Answer:
$2y$10$KwKceUaG84WInAif5ehdZOkE4kHPWTLp0ZK5a5OU2EbtdwQ9YIcGy
Example:
echo password_hash("abcDEF", PASSWORD_BCRYPT);
Answer:
$2y$10$SNly5bFzB/R6OVbBMq1bj.yiOZdsk6Mwgqi4BLR2sqdCvMyv/AyL2
To use the BCRYPT, set option cost=12 in an $options, also change first parameter $password to some strong password like "wgt167yuWBGY##1987__".
Example:
echo password_hash("wgt167yuWBGY##1987__", PASSWORD_BCRYPT, ['cost' => 12]);
Answer:
$2y$12$TjSggXiFSidD63E.QP8PJOds2texJfsk/82VaNU8XRZ/niZhzkJ6S