Module sha2

The SHA-2 cryptographic hash functions.

sha2 provides implementations of the SHA-2 family of cryptographic hash functions.

The SHA-2 family includes six hash functions: SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224, and SHA-512/256. These are cryptographic hash functions standardized by NIST, producing fixed-size digests from arbitrary input data. SHA-256 and SHA-512 are the most commonly used variants.

The crate implements the Digest trait, providing both one-shot hashing via Digest::digest and incremental hashing via Digest::new, Digest::update, and Digest::finalize.

A digest is a fixed-size byte array, not a string. Use the hex crate to render one for display or storage.

Examples

One-shot SHA-256 hashing:

use sha2::{Digest, Sha256};

let digest = Sha256::digest(b"hello world");

assert_eq!(
    hex::encode(digest),
    "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9",
);

Incremental hashing, for data that does not arrive all at once:

use sha2::{Digest, Sha256};

let mut hasher = Sha256::new();
hasher.update(b"hello ");
hasher.update(b"world");
let digest = hasher.finalize();

assert_eq!(digest, Sha256::digest(b"hello world"));

The variants differ only in digest length and internal state size:

use sha2::{Digest, Sha256, Sha384, Sha512};

assert_eq!(Sha256::digest(b"hello world").len(), 32);
assert_eq!(Sha384::digest(b"hello world").len(), 48);
assert_eq!(Sha512::digest(b"hello world").len(), 64);

Modules

Structs