# SHA-512/256

> cryptographic hash function

**Wikidata**: [Q110651437](https://www.wikidata.org/wiki/Q110651437)  
**Source**: https://4ort.xyz/entity/sha-512-256

## Summary
SHA-512/256 is a cryptographic hash function that belongs to the SHA-2 family of hash functions designed by the NSA, providing a 256-bit hash output from 512-bit input blocks.

## Key Facts
- It is a cryptographic hash function
- Part of the SHA-2 family of cryptographic hash functions
- Designed by the National Security Agency (NSA)
- Inception year: 2002 (as part of the SHA-2 family)
- Produces 256-bit hash values from 512-bit input blocks
- Related to standard cryptographic hash functions with specific cryptographic properties
- Has a sitelink count of 26 (for SHA-2 parent)

## FAQs
### Q: What is the main difference between SHA-512 and SHA-512/256?
A: SHA-512/256 is a variant of SHA-512 that produces a 256-bit hash output instead of the full 512-bit output of the original SHA-512.

### Q: Which family does SHA-512/256 belong to?
A: It belongs to the SHA-2 family of cryptographic hash functions designed by the NSA.

### Q: What is the input block size for SHA-512/256?
A: The input block size is 512 bits.

### Q: What is the hash output size for SHA-512/256?
A: The hash output size is 256 bits.

## Why It Matters
SHA-512/256 represents an important evolution in cryptographic hash function design, offering a balance between security and computational efficiency. It addresses the need for a hash function that provides the security strength of SHA-512 while reducing the output size to 256 bits, making it suitable for applications where smaller hash values are preferred or where computational resources are limited. This variant demonstrates how cryptographic standards can be adapted to meet specific performance and security requirements in different cryptographic contexts.

## Notable For
- It is a variant of the SHA-2 family that produces a 256-bit hash output
- It maintains the 512-bit input block size characteristic of SHA-2
- It was designed to provide a middle ground between the full 512-bit SHA-512 output and the 224/256-bit variants
- It offers a security level comparable to SHA-256 while using a larger input block size
- It represents a specific implementation of the SHA-2 family with a modified output size

### Technical Specifications
SHA-512/256 follows the same core structure as other SHA-2 functions but truncates the final hash value to 256 bits. The algorithm processes 1024-bit data blocks through a series of compression functions, message expansion, and modular arithmetic operations, similar to other SHA-2 members. This variant maintains the same security properties as the original SHA-512 while providing a more compact output.

### Relationship to Other SHA-2 Variants
The SHA-2 family includes several variants with different output sizes:
- SHA-224 (224-bit output)
- SHA-256 (256-bit output)
- SHA-384 (384-bit output)
- SHA-512 (512-bit output)
- SHA-512/224 (224-bit output)
- SHA-512/256 (256-bit output)

These variants allow users to select the appropriate hash size based on their specific security and performance requirements, demonstrating the flexibility of the SHA-2 design.

### Security Properties
Like other SHA-2 functions, SHA-512/256 is designed to be collision-resistant and preimage-resistant, making it suitable for various cryptographic applications including digital signatures, data integrity verification, and key derivation. The algorithm's security is based on the complexity of solving the underlying mathematical problems, which remains computationally infeasible with current technology.

### Implementation Considerations
The 256-bit output size of SHA-512/256 makes it particularly useful in scenarios where storage or bandwidth is limited, or where compatibility with systems that expect 256-bit hash values is required. Despite the truncated output, it maintains the full security strength of the underlying SHA-512 algorithm, providing a reliable cryptographic solution for applications requiring moderate to high security levels.