- 2023 Sep 02

**Introduction:**

In today’s world, where we have a vast amount of information with us, the need for methods to manage and secure this information is strongly felt. Hash and hash functions are important tools that help us transform information in a way that can be used as digital signatures for passwords and other purposes. In this article, we will explore this concept and its applications.

**What does hashing mean?**

Hashing is a mathematical process that transforms input data into a unique and constant value. The input data can be characters, numbers, images, and so on, which are converted into encoded output. The resulting hash value is typically a numerical or byte string. In simpler terms, hashing is like an abstract machine that generates a specific output value for each specific input.

As an example, a hashing function for the word “hello” provides you with the following output: “bda1fa48345336618741fd2cbc02809eb099c49a9b02fb5056401ab6ddc3e6”.

**Hashing process**

Hashing refers to the output of a hash function and the use of a hash function to generate a hash. Anyone with expertise in cryptography and mathematics can create their own hash function using these sciences. Currently, there are various types of hash functions, with the most important hashing algorithms being MD5, SHA-1, SHA-256, and SHA-3. These algorithms are widely used and play a crucial role in information security.

**The logic of hash function operation**

-The input is received: an input message (such as text, file, etc.) is passed as an input to the hash function. This input can be a text string, a file, or a data block.

-Processing: The hash function utilizes complex mathematical algorithms to process the input message. These algorithms perform specific computational operations on the input bits and produce the result as the output hash.

-Hаsh output is generated: The processing process results in the generation of a unique and fixed hаsh output. This hаsh output is usually a shorter string than the input message and is commonly used as a representative of the unique message. This hаsh value may be displayed as a string of hexadecimal numbers and letters (from 0 to 9 and A to F).

**The most important feature of a hash function**

The most important feature is that a small change in the input results in a complete change in the hаsh value. In other words, even a minor change in the input will generate a completely different hаsh value. This feature is known as “avalanche effect” and is very useful in applications that require detecting changes in data (such as security checks or data integrity verification).

Please keep in mind that each hаsh function has its own specific algorithm, and its operational logic may vary depending on the type of hаsh function. In addition, hаsh functions such as MD5, SHA-256, and SHA-3 are used in various fields, including encryption, digital signatures, and information security.

** Cryptographic hash function**

The hаsh function is designed for use in encryption and information security. One of its important features is its one-way functionality, meaning that it is not easy to retrieve the original input data from the hаsh output. A cryptographic hаsh function should have important security properties. For example, a small change in the input should result in a drastic change in the generated output. Additionally, the possibility of recovering the original data from the hаsh output using inverse or randomization methods should be extremely low.

**The famous cryptographic hash functions**

SHA-256 (Secure Hаsh Algorithm 256-bit) and MD5 (Message Digest Algorithm 5) are used in many systems and applications. These hаsh functions are widely used due to their security features and strong performance in areas such as data encryption, digital signature, verification, and security systems.

**SHA-256 Hash Function**

SHA-256 (Secure Hash Algorithm 256-bit) is a cryptographic hаsh function that converts an input text into a 256-bit hаsh value. This function is used for generating unique and secure hashes. However, SHA-256 is a one-way function, meaning it is not possible to retrieve the original text from the hаsh.

**MD5 Hash Function**

The MD5 (Message Digest Algorithm 5) hаsh function is used to generate a unique and constant hаsh value from an input. The main objective of MD5 is to create a 128-bit (or 16-byte) hаsh value for each input, which is represented as a recognized string of hexadecimal numbers and characters. MD5 can calculate hаsh values quickly and efficiently, but its security is weak for certain applications. If your program or system requires high security, it is recommended to use stronger hаsh functions such as SHA-256 or SHA-3.

**The SHA (Secure Hash Algorithm) algorithm**

A collection of secure hаsh functions that have been designed and published by the National Institute of Standards and Technology (NIST) in the United States. Different versions of the SHA algorithm include:

-SHA-1: This version of the SHA algorithm generates a 160-bit hаsh value for inputs. Over time, security vulnerabilities have been identified in SHA-1, and it is recommended to refrain from using it as a secure hаsh function.

-SHA-224 and SHA-256: SHA-224 generates a 224-bit hаsh value and SHA-256 generates a 256-bit hаsh value. These versions provide stronger cryptographic properties compared to SHA-1 and have been proposed as better replacements for it.

-SHA-384 and SHA-512: SHA-384 generates a 384-bit hаsh value, and SHA-512 generates a 512-bit hаsh value. These versions of hаsh functions have larger sizes compared to SHA-256 and are used for certain applications such as securing sensitive information.

-SHA-3: SHA-3 is a family of hаsh algorithms that are presented in three different versions with various sizes (SHA-3-224, SHA-3-256, and SHA-3-512). SHA-3 is based on a new structure called Keccak and is used as a replacement for SHA-2. It’s important to note that SHA-2 (including SHA-224, SHA-256, SHA-384, and SHA-512) and SHA-3 are two separate families of hаsh algorithms and they differ from each other. Each of these versions may be suitable for your specific needs and purposes.

**RIPEMD (RACE Integrity Primitives Evaluation Message Digest****)**

A family of hаsh functions is designed for generating hаsh values with a length of 128 bits or 160 bits. The goal of a hаsh function is to take an input, such as a message or file, and produce a fixed output called the hаsh value. Key features of a good hаsh function include unique output generation speed for different inputs and resistance to collisions (the occurrence of two different inputs producing the same output).

RIPEMD obtains its objectives through the combination of bitwise operations, rotation functions, and logical operations such as XOR. It divides the input into blocks and performs a series of operations on each block to obtain the final hаsh value. The specific operations used in RIPEMD are designed to provide output with desired characteristics.

**Whirlpool**

Whirlpool is a strong and resilient hash function algorithm designed to generate 528-bit hash values, which is resistant to attacks. The primary goal of the Whirlpool hash function is to take an input such as a message or file and produce a unique and constant hash value. This hash value can be used for purposes such as verifying data integrity, digital signatures, preventing unauthorized changes, and other security processes.

Whirlpool uses a structure called Merkle-Damgård, which divides the input into smaller blocks and performs a series of operations on each block to obtain the final hash value. This algorithm utilizes bitwise addition, bitwise rotation, S-Box (substitution box) functions, and modular addition and subtraction to perform the hashing operations.

Whirlpool possesses important properties such as resistance against preimage attacks, resistance against second preimage attacks, and resistance against collisions. This algorithm is used as one of the strong and complex hash function algorithms in many security applications and protocols.

**BLAKE**

Blake is a strong and secure hash function algorithm designed to generate hash values with adjustable length. The main goal of the Blake hash function is to take input such as a message or a file and produce a constant and unique hash value. The hash value can be used for information security, data integrity verification, prevention of unauthorized changes, and other cryptographic and security processes.

**Blake (Flower)**

Blake uses a structure called (Flower), which divides the input into smaller blocks and performs a series of operations on each block to obtain the final hash value. These operations include bitwise addition, bitwise rotation, S-Box function, and modular addition and subtraction function.

Blake has desirable security properties and is resistant to preimage attacks, second preimage attacks, and collisions. This algorithm is adjustable and can be used to generate hash values of different lengths.

**Blake and Hash function**

Blake is a well-known hash function algorithm used in many encryption programs, digital signatures, and security systems. However, it is recommended to use the standard and secure versions of Blake and other hash function algorithms, and pay attention to appropriate security testing and evaluation methods.

**Hashing in cryptocurrencies**

-Transaction Verification: When a transaction occurs in a blockchain, its information is passed as input to a hash function. The resulting hash value is considered a “transaction signature.” Using this signature, the authenticity of the transaction can be easily verified, and any changes to the transaction data can be prevented.

-Digital Signature Security: The process of digital signature also utilizes hashing. When an individual wants to sign a transaction, they input the transaction data into a hash function to calculate the hash value. Then, using their private key, they encrypt the hash value and add it to the transaction as a digital signature.

-Hashing Security: Since the hash function is one-to-one, meaning that each input value corresponds to only one hash value, it is very difficult to tamper with or modify the data. Additionally, it is not possible to retrieve the original data from the hash, which means that even if we have the hash of a transaction in a blockchain block, we cannot directly access the transaction data.

-Types of hash functions: In cryptocurrencies, commonly used hash functions such as SHA-256 (Secure Hash Algorithm 256-bit) are employed. This hash function is utilized to generate 256-bit hashes. The large number of bits in the hash ensures a greater emphasis on the security and accuracy of transactions.

**Blockchain immutability**

Blockchain is an advanced technology used in cryptocurrencies like Bitcoin. One of the important features of blockchain is its immutability.

Immutability in the context of blockchain refers to the inability to change data once it has been recorded in a block. Each block in a blockchain contains information such as transactions, signatures, and other relevant data pertaining to that block. The blocks are connected to each other in a continuous manner, with each block referencing its previous block. These references are stored in a transparent and clear manner.

**Factors ensuring the security and integrity of information with immutability in blockchain**

-Hash Function Usage: In blockchain, hash functions are used. These functions convert input data into a numerical string known as a hash. One characteristic of a hash function is that even a small change in the input data completely changes the hash value. This characteristic means that any changes in blocks and transactions can be easily identified.

-Using Blockchain: Blockchain is available to a network of interconnected computers. These computers are known as network nodes, and the presence of many nodes in the network enables the verification and validation of blocks and transactions. Any change in the blockchain must be approved by the majority of nodes in order to be implemented. This ensures high security and prevents unintended changes to the blockchain.

**Mining**

Mining is one of the key elements in the process of creating cryptocurrencies such as Bitcoin.

М**ining Concept**

Mining is an activity in which cryptocurrencies are extracted by computers. Essentially, miners (individuals who perform this activity) use the computational power of their computers to verify transactions occurring on the blockchain network and add them to a record called a “block”. These blocks are continuously linked together, forming a blockchain.

**Mining performance method**

The method of operation in mining is based on an algorithm called “Proof of Work.” In this method, miners compete to solve a complex mathematical problem. The first miner to solve the problem creates a new block and receives a reward in the form of digital currency. This reward is essentially a cost that the network pays to the miners, and it is also used to incentivize miners to continue their activities.

**Earn money from mining**

Мining can help individuals earn income by engaging in the process of mining and extracting cryptocurrencies. If miners successfully solve mathematical problems, they receive rewards in the form of cryptocurrency, which is deposited into their accounts. These cryptocurrencies can be traded on various markets or used as a unit of payment in buying and selling transactions. Additionally, some individuals may choose to rent out their mining equipment to others and generate income.

**Hash rate**

Нash rаtе is one of the important factors in mining and cryptocurrencies. Hash rаtе can be considered as the speed or capability of a device or network in performing computations and solving cryptographic problems. Imagine you are a miner and you are engaged in block extraction and earning cryptocurrencies. In this context, hash rate represents the number of computations you can perform per second. In other words, hash rate indicates how fast your device can solve complex mathematical problems. Hash rаte refers to the number of hashes generated per second by a device or network.

**Hash**

With the increase in hash rate, the speed of block mining and earning cryptocurrencies also increases. Therefore, miners with higher hash rates are likely to solve blocks faster and receive greater rewards. Нash rate can be improved by using more powerful equipment.

**Hash rate measurement standard**

One of the most common measures for measuring hash rate is “hashes per second.” This number indicates the number of hashes computed in one second, based on the algorithm type and network difficulty. It is worth mentioning that hash rates of different algorithms cannot be compared with each other.

The measurement criteria for hash rates, which essentially involve only unit conversions, are as follows:

- 1 KH/s or one thousand hashes per second.
- 1 MH/s or one million hashes per second.
- 1 GH/s or one billion hashes per second.
- 1 TH/s or one trillion hashes per second.
- 1 PH/s or one quadrillion hashes per second.
- 1 EH/s or one quintillion hashes per second.

The above numbers are named in the following order: kilohash, megahash, gigahash, terahash, petahash, and exahash.