What is encryption salt

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By clicking sign up, you agree to receive emails from Techopedia and agree to our Terms of Use and Privacy Policy. Password salting is a form of password encryption that involves appending a password to a given username and then hashing the new string of characters. This is usually done via an MD5 hashing algorithm. Password-salting is most commonly found within Linux operating systems, and it is generally considered a more secure password encryption model than any of the models used within the various Microsoft distributions.

Because hash functions map arbitrary amounts of data to fixed-length strings, there must be some inputs that hash into the same string. Cryptographic hash functions are designed to make these collisions incredibly difficult to find. From time to time, cryptographers find "attacks" on hash functions that make finding collisions easier. A recent example is the MD5 hash function, for which collisions have actually been found. Collision attacks are a sign that it may be more likely for a string other than the user's password to have the same hash.

However, finding collisions in even a weak hash function like MD5 requires a lot of dedicated computing power, so it is very unlikely that these collisions will happen "by accident" in practice. A password hashed using MD5 and salt is, for all practical purposes, just as secure as if it were hashed with SHA and salt. This section describes exactly how passwords should be hashed. The first subsection covers the basics—everything that is absolutely necessary. The following subsections explain how the basics can be augmented to make the hashes even harder to crack.

Warning: Do not just read this section. We've seen how malicious hackers can crack plain hashes very quickly using lookup tables and rainbow tables. We've learned that randomizing the hashing using salt is the solution to the problem. But how do we generate the salt, and how do we apply it to the password?

As the name suggests, CSPRNGs are designed to be cryptographically secure, meaning they provide a high level of randomness and are completely unpredictable. The salt needs to be unique per-user per-password. Every time a user creates an account or changes their password, the password should be hashed using a new random salt.

Never reuse a salt. The salt also needs to be long, so that there are many possible salts. As a rule of thumb, make your salt is at least as long as the hash function's output. The salt should be stored in the user account table alongside the hash. If you are writing a web application, you might wonder where to hash. Should the password be hashed in the user's browser with JavaScript, or should it be sent to the server "in the clear" and hashed there?

Even if you are hashing the user's passwords in JavaScript, you still have to hash the hashes on the server. Consider a website that hashes users' passwords in the user's browser without hashing the hashes on the server. To authenticate a user, this website will accept a hash from the browser and check if that hash exactly matches the one in the database. This seems more secure than just hashing on the server, since the users' passwords are never sent to the server, but it's not.

The problem is that the client-side hash logically becomes the user's password. All the user needs to do to authenticate is tell the server the hash of their password.

If a bad guy got a user's hash they could use it to authenticate to the server, without knowing the user's password! So, if the bad guy somehow steals the database of hashes from this hypothetical website, they'll have immediate access to everyone's accounts without having to guess any passwords.

This isn't to say that you shouldn't hash in the browser, but if you do, you absolutely have to hash on the server too. Hashing in the browser is certainly a good idea, but consider the following points for your implementation:.

If the connection between the browser and the server is insecure, a man-in-the-middle can modify the JavaScript code as it is downloaded to remove the hashing functionality and get the user's password. Some web browsers don't support JavaScript, and some users disable JavaScript in their browser. So for maximum compatibility, your app should detect whether or not the browser supports JavaScript and emulate the client-side hash on the server if it doesn't.

You need to salt the client-side hashes too. The obvious solution is to make the client-side script ask the server for the user's salt. Don't do that, because it lets the bad guys check if a username is valid without knowing the password. Since you're hashing and salting with a good salt on the server too, it's OK to use the username or email concatenated with a site-specific string e.

Salt ensures that attackers can't use specialized attacks like lookup tables and rainbow tables to crack large collections of hashes quickly, but it doesn't prevent them from running dictionary or brute-force attacks on each hash individually.

High-end graphics cards GPUs and custom hardware can compute billions of hashes per second, so these attacks are still very effective. To make these attacks less effective, we can use a technique known as key stretching. The idea is to make the hash function very slow, so that even with a fast GPU or custom hardware, dictionary and brute-force attacks are too slow to be worthwhile. The goal is to make the hash function slow enough to impede attacks, but still fast enough to not cause a noticeable delay for the user.

Key stretching is implemented using a special type of CPU-intensive hash function. Don't try to invent your own—simply iteratively hashing the hash of the password isn't enough as it can be parallelized in hardware and executed as fast as a normal hash.

These algorithms take a security factor or iteration count as an argument. This value determines how slow the hash function will be. For desktop software or smartphone apps, the best way to choose this parameter is to run a short benchmark on the device to find the value that makes the hash take about half a second. This way, your program can be as secure as possible without affecting the user experience.

If you use a key stretching hash in a web application, be aware that you will need extra computational resources to process large volumes of authentication requests, and that key stretching may make it easier to run a Denial of Service DoS attack on your website. I still recommend using key stretching, but with a lower iteration count. You should calculate the iteration count based on your computational resources and the expected maximum authentication request rate.

Always design your system so that the iteration count can be increased or decreased in the future. If you are worried about the computational burden, but still want to use key stretching in a web application, consider running the key stretching algorithm in the user's browser with JavaScript. The iteration count should be set low enough that the system is usable with slower clients like mobile devices, and the system should fall back to server-side computation if the user's browser doesn't support JavaScript.

Client-side key stretching does not remove the need for server-side hashing. You must hash the hash generated by the client the same way you would hash a normal password. As long as an attacker can use a hash to check whether a password guess is right or wrong, they can run a dictionary or brute-force attack on the hash.

The next step is to add a secret key to the hash so that only someone who knows the key can use the hash to validate a password. This can be accomplished two ways. Either the hash can be encrypted using a cipher like AES, or the secret key can be included in the hash using a keyed hash algorithm like HMAC.

This is not as easy as it sounds. The key has to be kept secret from an attacker even in the event of a breach. If an attacker gains full access to the system, they'll be able to steal the key no matter where it is stored. The key must be stored in an external system, such as a physically separate server dedicated to password validation, or a special hardware device attached to the server such as the YubiHSM. I highly recommend this approach for any large scale more than , users service.

I consider it necessary for any service hosting more than 1,, user accounts. If you can't afford multiple dedicated servers or special hardware devices, you can still get some of the benefits of keyed hashes on a standard web server. Most databases are breached using SQL Injection Attacks , which, in most cases, don't give attackers access to the local filesystem disable local filesystem access in your SQL server if it has this feature.

If you generate a random key and store it in a file that isn't accessible from the web, and include it into the salted hashes, then the hashes won't be vulnerable if your database is breached using a simple SQL injection attack. Don't hard-code a key into the source code, generate it randomly when the application is installed. This isn't as secure as using a separate system to do the password hashing, because if there are SQL injection vulnerabilities in a web application, there are probably other types, such as Local File Inclusion, that an attacker could use to read the secret key file.

But, it's better than nothing. Please note that keyed hashes do not remove the need for salt. Clever attackers will eventually find ways to compromise the keys, so it is important that hashes are still protected by salt and key stretching.

Password hashing protects passwords in the event of a security breach. It does not make the application as a whole more secure. Much more must be done to prevent the password hashes and other user data from being stolen in the first place. Even experienced developers must be educated in security in order to write secure applications. Unless you understand all the vulnerabilities on the list, do not attempt to write a web application that deals with sensitive data.

It is the employer's responsibility to ensure all developers are adequately trained in secure application development. Having a third party "penetration test" your application is a good idea. Even the best programmers make mistakes, so it always makes sense to have a security expert review the code for potential vulnerabilities.

Find a trustworthy organization or hire staff to review your code on a regular basis. The security review process should begin early in an application's life and continue throughout its development. It is also important to monitor your website to detect a breach if one does occur.

I recommend hiring at least one person whose full time job is detecting and responding to security breaches. If a breach goes undetected, the attacker can make your website infect visitors with malware, so it is extremely important that breaches are detected and responded to promptly. Even though there are no cryptographic attacks on MD5 or SHA1 that make their hashes easier to crack, they are old and are widely considered somewhat incorrectly to be inadequate for password storage.

So I don't recommend using them. It is my personal opinion that all password reset mechanisms in widespread use today are insecure. If you have high security requirements, such as an encryption service would, do not let the user reset their password.

Most websites use an email loop to authenticate users who have forgotten their password. To do this, generate a random single-use token that is strongly tied to the account.

Include it in a password reset link sent to the user's email address. When the user clicks a password reset link containing a valid token, prompt them for a new password.

Be sure that the token is strongly tied to the user account so that an attacker can't use a token sent to his own email address to reset a different user's password. The token must be set to expire in 15 minutes or after it is used, whichever comes first.

It is also a good idea to expire any existing password tokens when the user logs in they remembered their password or requests another reset token.

Hashes are inherently unidirectional, so this makes hashing an excellent way to store passwords in the database. It is very difficult to access the raw data or to invert it into its original form. As the stored passwords in hash format, to access raw data to invert it into its original form. If you own a website and want your users to sign in. At first, you should hash the passwords for your users while they are signing up.

Later when your user attempts to login then compare it with your stored hash. As both, the password matches the user gets to access his account.

If you change a single position of a single character or add a new character of the hash key, it changes the entire hash drastically. While examining Hashing vs Encryption, you cannot use the above-hashed key via reverse function to retain the original input again.

Hashing also proves to be very convenient while monetizing your website or app data. It is the most secured way to protect your data while you are sharing your valuable information for data monetization or data exchanges. The prime difference between encryption and hashing is that the entire process is based upon a key system.

If decrypting the resulting data is necessary, then encryption should only be employed instead of hashing. Let us assume that if you want to send a piece of secure information to someone in a discreet manner. Encryption is the best way to secure your data compared to hashing. As the transmitted data is of no use to the recipient if they cannot decrypt it.

If the information you sent is restricted to be identified for any application to work on. At that instant hashing should be chosen over encryption.

While weighing hashing vs encryption, hashing is more reliable and secure. A hash is a number that generates from a text through a hash algorithm. This number is smaller than the original text. If you understand what hashing is, this will make it much easier for you to understand salting.

Salting is generally related to hashing and making passwords more secure in the process of hashing. It is a unique value that may be a text, numerals, symbols or combinations of them, which are added to the end of the password before it is hashed to generate a different hash value. This certainly adds an additional layer of protection to the hashing method, particularly against cyber brute force intrusions. A computer network or botnet generates a brute force attack to crack the passwords.

It is a trial or error which runs in every imaginable combination of letters and numbers to recognize the right combination by the attacker. Salt can be anything letters or numerals. A salt is used so that the same password does not always generate the same key; however, because the recipient must be able to generate the correct key, the salt must be transmitted along with the encrypted data.

In this case, it used to ensure that the same plaintext data under the same key does not always encrypt to the same ciphertext. Again, the IV is required by the recipient to correctly decrypt the data, so it must be transmitted along with the encrypted data. View all posts by Bay D. You are commenting using your WordPress. You are commenting using your Google account.