SSL/SSH protects data travelling from the client to the server: SSL/SSH does not protect persistent data stored in a database. SSL is an on-the-wire protocol.
Once an attacker gains access to your database directly (bypassing the webserver), stored sensitive data may be exposed or misused, unless the information is protected by the database itself. Encrypting the data is a good way to mitigate this threat, but very few databases offer this type of data encryption.
The easiest way to work around this problem is to first create your own encryption package, and then use it from within your PHP scripts. PHP can assist you in this with several extensions, such as Mcrypt and Mhash, covering a wide variety of encryption algorithms. The script encrypts the data before inserting it into the database, and decrypts it when retrieving. See the references for further examples of how encryption works.
In the case of truly hidden data, if its raw representation is not needed (i.e. will not be displayed), hashing should be taken into consideration. The well-known example for hashing is storing the cryptographic hash of a password in a database, instead of the password itself.
In PHP 5.5 or newer password functions provide convinient way to hash sensitive data and work with these hashes. In PHP 5.3.7+ ยป password_compat library can also be used.
password_hash() is used to hash given string using strongest algorithm currently available and password_verify() checks whether given password matches the hash stored in database.
Example #1 Hashing password field
<?php
// storing password hash
$query = sprintf("INSERT INTO users(name,pwd) VALUES('%s','%s');",
pg_escape_string($username),
password_hash($password, PASSWORD_DEFAULT));
$result = pg_query($connection, $query);
// querying if user submitted the right password
$query = sprintf("SELECT pwd FROM users WHERE name='%s';",
pg_escape_string($username));
$row = pg_fetch_assoc(pg_query($connection, $query));
if ($row && password_verify($password, $row['pwd'])) {
echo 'Welcome, ' . htmlspecialchars($username) . '!';
} else {
echo 'Authentication failed for ' . htmlspecialchars($username) . '.';
}
?>
In older versions of PHP this can be achieved using crypt() function.
Example #2 Hashing password using crypt()s
<?php
// storing password hash
// $random_chars retrieved e.g. using /dev/random
$query = sprintf("INSERT INTO users(name,pwd) VALUES('%s','%s');",
pg_escape_string($username),
pg_escape_string(crypt($password, '$2a$07$' . $random_chars . '$')));
$result = pg_query($connection, $query);
// querying if user submitted the right password
$query = sprintf("SELECT pwd FROM users WHERE name='%s';",
pg_escape_string($username));
$row = pg_fetch_assoc(pg_query($connection, $query));
if ($row && crypt($password, $row['pwd']) == $row['pwd']) {
echo 'Welcome, ' . htmlspecialchars($username) . '!';
} else {
echo 'Authentication failed for ' . htmlspecialchars($username) . '.';
}
?>
I would strongly recommend using SHA-2 or better the new SHA-3 hash algorithm. MD5 is practically unusable, since there are very well working rainbow tables around the whole web. Almost the same for SHA-1. Of course you should never do a hash without salting!
Using functions to obfuscate the hash generation does not increase security. This is security by obscurity. The algorithm used to hash the data needs to be secure by itself.
I would not suggest to use other data as salt. For example if you use the username, you won't be able to change the values without rehashing the password.
I would use a dedicated salt value stored in the same database table.
Why? Because a lot of users use the same login credentials on different web services. And in case another service also uses the username as salt, the resulting hashed password might be the same!
Also an attacker may prepare a rainbow table with prehashed passwords using the username and other known data as salt. Using random data would easily prevent this with little programming effort.
A better way to hash would be to use a separate salt for each user. Changing the salt upon each password update will ensure the hashes do not become stale.
It's difficult to post scripts here for all to view on the subject of best security practices. But i would wish to point out that using a salt with a randomized and odd numbered long length salt value is do_able with two Php functions while retrieving and separating the salt when it comes out using simple math functions. But with everything we add we also have to think of the constant standardized login systems we stay behind with.
For one,,, adding and validating two to four passwords is not a bad idea. Also having no username or email going in. They can be stored after the user logs in after the validation process. It is possible to store the email on the first signup and only at that time. And if the user loses his passwords then validate by email only upon request within a contact form by a validated phone number stored in the database,, and then via their email account.
I think the best way to have a salt is not to randomly generate one or store a fixed one. Often more than just a password is saved, so use the extra data. Use things like the username, signup date, user ID, anything which is saved in the same table. That way you save on space used by not storing the salt for each user.
Although your method can always be broken if the hacker gets access to your database AND your file, you can make it more difficult. Use different user data depending on random things, the code doesn't need to make sense, just produce the same result each time. For example:
if ((asc(username character 5) > asc(username character 2))
{
if (month the account created > 6)
salt = ddmmyyyy of account created date
else
salt = yyyyddmm of account created date
}
else
{
if (day of account created > 15)
salt = user id * asc(username character 3)
else
salt = user id + asc(username character 1) + asc(username character 4)
}
This wont prevent them from reading passwords when they have both database and file access, but it will confuse them and slow them up without much more processing power required to create a random salt
I am not sure if this method is secure but i encrypt a users password with mcrypt and save the random character salt to a file that is protected by the web server. The filename is there unique id + date registered encrypted with standard md5.
For extra security if the ip address is not the normal ip address i send a little notification to there email.
