# Cryptographic Hashing

Crypto hashing refers to the process of converting an input (or “message”) into a fixed-size string of bytes using a cryptographic hash function. The output, typically called the “hash value” or “digest,” is unique to each unique input. Even a small change in the input will produce a completely different hash, a property known as the avalanche effect. Cryptographic hashing is a fundamental component of many security protocols and blockchain technologies.

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## **Key Properties of Cryptographic Hash Functions**

A good cryptographic hash function has the following essential properties:

1. **Deterministic**: The same input will always produce the same hash output, ensuring consistency.
2. **Fast Computation**: Hashing should be computationally efficient, allowing quick processing of large amounts of data.
3. **Pre-image Resistance**: Given a hash output, it should be computationally infeasible to find the original input. This property prevents attackers from reversing the hash function.
4. **Small Changes in Input Produce Large Changes in Output**: A tiny change in the input (even a single bit) should produce a drastically different hash output, a property known as the **avalanche effect**.
5. **Collision Resistance**: It should be computationally infeasible to find two different inputs that produce the same hash output. This is crucial for maintaining the integrity of data.
6. **Second Pre-image Resistance**: It should be difficult to find another input that produces the same hash as a given input, even if the first input is known.

## **Popular Cryptographic Hash Algorithms**

Everything explain in Subpages and everything implemting using Golang or Rust&#x20;

* [Secure Hash Algorithms stands for Sha](https://app.gitbook.com/o/XZINBDhIR1gHbqNA63Tp/s/2zO36jFtIGot9FwToN71/)
* [Message Digest ](https://app.gitbook.com/o/XZINBDhIR1gHbqNA63Tp/s/2zO36jFtIGot9FwToN71/~/changes/12/cryptographics/cryptographic-hashing/message-digest-algorithms)
* [Ethash ](https://app.gitbook.com/o/XZINBDhIR1gHbqNA63Tp/s/2zO36jFtIGot9FwToN71/~/changes/12/cryptographics/cryptographic-hashing/ethash)
* [Blake2](https://app.gitbook.com/o/XZINBDhIR1gHbqNA63Tp/s/2zO36jFtIGot9FwToN71/~/changes/12/cryptographics/cryptographic-hashing/blake2)
* [SCrypt](https://app.gitbook.com/o/XZINBDhIR1gHbqNA63Tp/s/2zO36jFtIGot9FwToN71/~/changes/12/cryptographics/cryptographic-hashing/scrypt)
* [RIPEMD-160](https://app.gitbook.com/o/XZINBDhIR1gHbqNA63Tp/s/2zO36jFtIGot9FwToN71/)

## **Applications of Cryptographic Hashing**

1. **Data Integrity Verification**: Hashing is used to ensure data integrity by comparing the hash of original data with the hash of received data. If the hashes match, the data has not been tampered with.
2. **Digital Signatures and Certificates**: Hash functions are used in creating digital signatures, where the hash of a message is encrypted with a private key to ensure authenticity and integrity.
3. **Password Hashing**: When storing passwords, systems store hashes instead of the plaintext passwords. When a user logs in, the system hashes the entered password and compares it to the stored hash.
4. **Blockchain**: Cryptographic hashes are fundamental to blockchain technology, where they link blocks together, ensure data integrity, and provide proof-of-work mechanisms.
5. **Checksum Generation**: Hashes are used to create checksums that help in error detection in data storage and transmission.
6. **Message Authentication Codes (MACs)**: Hash functions are used in MACs, which verify the integrity and authenticity of a message by creating a hash using a secret key.

## **Why Cryptographic Hashing is Important**

* **Security**: Provides a secure way to verify data integrity without revealing the data itself.
* **Speed**: Hash functions are designed to be fast, enabling quick checks and operations on large datasets.
* **Simplicity**: Hashing provides a simple yet powerful tool for verifying data integrity, essential for many cryptographic protocols.

## **Limitations**

* **Collision Vulnerabilities**: Some older algorithms like MD5 and SHA-1 are susceptible to collisions, making them insecure for modern use.
* **No Encryption**: Hashing does not encrypt data; it only provides a unique representation of the data. It is not reversible, unlike encryption.
