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You would have probably heard the four-letter word “hash” while going through mathematical codes. Hence, in cryptography **hash function** is related to the mathematical process. We will discuss hash which relates to cryptography here.

A **hash function** plays a captious role in public-key cryptography because it helps you to in the following ways;

- It is securing the data in different applications that indicate the altered data.
- Ensure possible authentication security
- Store passwords in the information section or database, and
- Create and manage files and content with greater efficiency.

Moreover, in daily life, you can find several hash functions. For instance, you can easily sign in to the software applications while using your cell phones. Another **hash function example** is it can help you find secure internet connections to transmit information online.

Above all, have you got any idea what a **hash function is in cryptography**? Where will you find hashes in use? and what does a **hash function** do? Stay with us to know more about the** hash function.**

**What is a Hash Function?**

**A fixed-length text hash function in cryptography** is an algorithm that gains input data and gives a fixed output. The output is known as a hash or a hash value. This value can be used instead of a password and can be used for verification of users.

Another definition of a hash function is, it is a distinct symbol for any content. Furthermore, it takes variable text datasets, a mathematical algorithm, and changes into a fixed-length text.

While hashing data, the resulting text can be smaller than input text except for hashing passwords. When you are doing hashing, it doesn’t matter whether it is one-sentence text or a whole book.

Hence, the output will still be of a specific length of 1s and 0s bits. That will prevent the unknown parties from figuring out how small or big the input message was.

**Properties of Strong Hash Algorithms**

If you are dealing with hashing, you must know a strong hashing algorithm. There are some properties of strong hash algorithms, and these explain the below pages.

**Determinism**

A strong hash algorithm must be deterministic. It means that when you are giving input, you will always get an identical size output.

For example, if you are hashing a piece of a sentence, the output must be of the same size. You will get the same size of that sentence if you are hashing a whole book.

**Pre-image Resistance**

Pre-image resistance is the set of values that make a specific hash. Consequently, if you want to reverse the hash value to get the input plain text, it will not be possible. Hence, you can say that a strong hash algorithm must be pre-image resistance. On the other hand, you can say that hashes are one-way functions or irreversible.

By looking at the given output, an attacker will try to guess the given input. Hence, pre-image resistance is the property that protects valuable data because any small change in the message can determine authenticity.

**Collision Resistance**

It is stated that when two objects collide, a collision occurs. The **hash function in cryptography** contains the concept of collision resistance in hash values. If you give input of two different samples and the result is a similar output, it is a collision.

If you are hashing to similar encoded text, you cannot determine two passwords easily. The hash algorithm will be strong if there is resistance to any collisions that occur there.

Subsequently, one of compressing functions is the **hash function** with a fixed length. It is the chance of having collisions in the hash function. Hence, the Collision resistance property of the hash function confirms that it is hard to find collisions in the hash function.

**Avalanche Effect**

The name avalanche effect is used in hash algorithms as there is a slight change in output always. It is also named diffusion. For example, if you change a password slightly, there is a significant and erratic change in output. You can also state it as a slight change in output if any change is made to input, whether small or large.

In the hash value algorithm, a minor alteration in input can cause drastic changes in the hash value. If you flip a single bit in input, you will get a half-flip in the hash value as well.

If a keyword is changed minimally, there will be a significant change in ciphertext. For instance, if this property exists in a hash function, an attacker cannot predict the plain text easily.

**What Does a Hash Function Do?**

**The hash function in cryptography** is based on the primary purpose. That is, it gains input of plain text and gives output as a specific sized hashed value. In the field of cryptography, hash functions perform the best role. Some of the main functions of hash functions are:

**Ensure Data Integrity**

Hash functions play a vital role in cryptography to ensure data integrity. It means that the hash function identifies the data that is a tamper. For verification processes, hash functions serve the central part. It generates checksums on the data files. However, there isn’t any assurance of originality of data.

The checksum or integrity check will help you to detect the changes if made in an original file. For example, somebody can easily change the entire file instead of modifying data. They may also calculate overall data to a new hash and then send it to the receiver. Hence, this application of the **hash function** is used to assure the user about the originality of the file.

**Secure Against Unauthorized Modifications**

**Hash function** in cryptography is based on another aspect that is it helps in ensuring data integrity. However, if somebody applies a hash to data, it doesn’t mean that message can not change.

The **hash function** informs the recipient of the message that there has been a change in the messages; it will create a new hash value. Hence, the **hash function** secures users against unauthorized modifications.

**Enable You to Verify and Securely Store Passwords**

Hash functions secure you from storing passwords and verifying them. For example, many websites permit you to keep your passwords. You do this because you don’t have to remember the passwords when you sign in somewhere.

Consequently, storing passwords on various websites can be dangerous. These plain text passwords in public servers create issues because these servers leave information openly. Typically, these websites hash the passwords to create new hash values to store.

The trespasser is the person who can hash passwords only, even if he/she approached the password. Since **hash function** algorithms possess the pre-image resistance property, somebody can’t log in after hashing. Even he cannot get the passwords using hash values.

**Where You’ll Find Hashes in Use**

You have gained the idea of hashes and hash functions, but do you know where you find hash functions? You are surrounded by unlimited technology, so you can easily imagine hash functions around you. They are broadly used in the hash table to store the data and then retrieve them.

Hashing is utilized for verifying the data integrity of emails, documents, and other software. It also verifies the passwords and also stores hashes of passwords. Hashing also verifies data blocks in various technologies, i.e., in blockchain and cryptocurrencies.

For instance, the largest cryptocurrency is bitcoin; it uses the hash function SHA-256 in the algorithm. Moreover, hash functions are broadly found in cryptography. You will find hash functions in various fields, for example in:

- Code signing certificates,
- Email signing certificates,
- TLS certificates,
- SSL certificates, and
- Document signing certificates

**Frequently Asked Questions (FAQs)**

**What you meant by hash function?**

A hash function is used to produce new values according to the given input with specific algorithms. The result generated from the hash function is a hash value or hash.

**What is a hash function example?**

An example of the hash function is, if the output is 0-9 hash range, you can interpret the input as a base-ten integer.

**What is hashing used for?**

Hashing is used in various encryption algorithms. Hashing helps you to index and regain database items. Hence, by using hash code, you can more easily find the item than using the original one.

**What is the best hash function?**

Most likely, one of the best hash functions commonly used is SHA 256 algorithm. That is recommended by the National Institute of Standards and Technology.

**Conclusion**

As we have seen, the **hash function** performs various functions. When you are dealing with a considerable amount of data, Hash functions are used. Mainly mathematicians use these hash functions with broad properties—for example, determinism, preimage resistance, collision resistance, and the avalanche effect.

Maybe cryptography will be the most anxious field in science. The hash functions will ensure your security in electronic networking. Consequently, hackers are aware of these hash functions and are creating advanced hacking techniques continuously.

If you are interested in blockchain technology, you must understand the properties and work of cryptographic hash functions.