rs_sha256

rs_sha256 is a Rust crate implementing the SHA-256 cryptographic hash algorithm. Configured for compatibility with Rust's libcore within a #![no_std] context, it operates as a standalone crate for specialized use cases and is also compatible with a #![no_std], #![no_alloc] environment, rendering it suitable for systems where dynamic memory allocation is untenable.

This implementation of SHA-256 is compliant with the Federal Information Processing Standards (FIPS) Publication 180-4[^1]. In line with the National Institute of Standards and Technology (NIST) guidelines, SHA-256 is recommended for several use cases:

"SHA-256 provides 128 bits of security against collision attacks and, therefore, is suitable for functions requiring a hash length of 128 bits."

Given this advice, NIST recommendations imply that SHA-256 is suitable for the following contexts:

• Digital signatures that require 128 bits of security.
• Cryptographic hash functions in systems and protocols requiring 128 bits of security.
• Authentication methods that necessitate 128 bits of security.

Beyond these specific recommendations, SHA-256 could also find application in:

• Version control systems for the generation of commit identifiers[^2].
• Hash-based message authentication codes (HMACs), when collision resistance is necessary[^3].
• Data integrity checks in Merkle Trees[^4].
• As a randomized hash function in Bloom filters[^5].

Given your overall security objectives and risk tolerance, these points should be carefully considered.

For access to a comprehensive range of cryptographic functions, rs_sha256 can be utilized as part of the rs_shield library bundle.

How To Use

Below are steps to use the rs_sha256 crate in your Rust projects:

1. Add the following line to your Cargo.toml under the [dependencies] section:

   rs_sha256 = "0.1.*"
   

2. Use the functions provided by the rs_sha256 module in your code. Here's an example of how to create a SHA-256 hash from a string:

   use rs_sha256::{HasherContext, Sha256Hasher};
   
   let mut sha256hasher = Sha256Hasher::default();
   sha256hasher.write(b"your string here");
   
   let u64result = sha256hasher.finish();
   let bytes_result = HasherContext::finish(&mut sha256hasher);
   assert_eq!(u64result, 0xEBEA8483C5B21AE6);
   assert_eq!(format!("{bytes_result:02x}"), "ebea8483c5b21ae61081786be10f9704ce8975e1e5b505c03f6ab8514ecc5c0c");
   assert_eq!(format!("{bytes_result:02X}"), "EBEA8483C5B21AE61081786BE10F9704CE8975E1E5B505C03F6AB8514ECC5C0C");
   assert_eq!(
       bytes_result,
       [
           0xEB, 0xEA, 0x84, 0x83, 0xC5, 0xB2, 0x1A, 0xE6, 0x10, 0x81, 0x78, 0x6B, 0xE1, 0x0F, 0x97, 0x04, 0xCE, 0x89,
           0x75, 0xE1, 0xE5, 0xB5, 0x05, 0xC0, 0x3F, 0x6A, 0xB8, 0x51, 0x4E, 0xCC, 0x5C, 0x0C
       ]
   )
   

More Information

For a more detailed exploration of rs_sha256, an overview of other available cryptographic functions, and an introduction to the broader rs_shield project, please consult the RustyShield project page on crates.io.

Contributions

Potential contributors are encouraged to consult the contribution guidelines on our GitHub page.

License

This project is licensed under GPL-2.0-only.

References

[^1]: National Institute of Standards and Technology. (2015). Secure Hash Standard (SHS). FIPS PUB 180-4

[^2]: Linus Torvalds. (2005). Git: A distributed version control system. Software: Practice and Experience, 41(1), 79-88. DOI:10.1002/spe.1006

[^3]: Krawczyk, H., Bellare, M., & Canetti, R. (1997). HMAC: Keyed-Hashing for Message Authentication. RFC 2104

[^4]: Merkle, R. C. (1988). A Digital Signature Based on a Conventional Encryption Function. Link

[^5]: Bloom, B. H. (1970). Space/time trade-offs in hash coding with allowable errors. Communications of the ACM, 13(7), 422-426. DOI:10.1145/362686.362692

Note: The references have been provided as per the best knowledge as of Jun 02, 2023.