## Overview#

A Cryptographic Hash Function (One-Way Hash Function OWHF) is a Hash Function with some additional MUST have all Hash Function Security Properties.If a Cryptographic Hash Function can **NOT** meet these requirements, the resulting hash is considered Cryptographically Weak.

### Most Common Cryptographic Hash Function#

The most commonly used Cryptographic Hash Function function today (2015-03-15) is SHA-1, which has output of 160 bits. (see SHAttered and SHA-1 Deprecation)### Strength of Cryptographic Hash Function#

Unlike with Ciphers, the strength of a Cryptographic Hash Function doesn’t equal the Hash length. Because of the Birthday Paradox (a well-known problem in probability theory), the strength of a Cryptographic Hash Function is at most one half of the Hash length.The harder it is to compute raises the Level Of Assurance.

Note that unlike hardness in most of complexity theory (e.g., NP-hardness), "hard" in the context of one-way functions refers to the Computational Hardness Assumption rather than worst-case hardness.

The existence of "pure" one-way functions is an open conjecture. for more information see Wikipedia:One-way_function

### Cryptographic Hash Function and Hash Function properties#

### More Information#

There might be more information for this subject on one of the following:- Bitcoin block
- Certificate Signature
- Crypt
- Cryptographic Hash Function Comparison
- Cryptographic Primitive
- Cryptography
- Digital Signature
- ES256
- Extendable-Output Function
- GOST
- HMAC-MD5
- HMAC-SHA1
- HMAC-SHA2
- Hash
- Hash Function
- JWK-Thumbprint
- Keyed-Hash Message Authentication Code
- MD5
- Master Secret
- Merkle-Damgard construction
- Message Authentication Code
- PBKDF2
- Preimage Resistance
- Record Protocol
- SHA-1
- SHA-2
- SHA-3
- SHAttered
- Second Preimage Resistance
- Secure Hash Algorithm
- TLS 1.3
- Time-based One-time Password Algorithm
- Verifying Certificate Signatures
- Zero-knowledge proof

- [#1] - Cryptographic Hash Functions - based on information obtained 2013-04-10
- [#1] - One-way_function - based on information obtained 2013-04-10