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//! `const fn` implementation of the SHA-2 family of hash functions.
//!
//! This crate allows you to use the SHA-2 hash functions as constant
//! expressions in Rust. For all other usages, the [`sha2`] crate includes more
//! optimized implementations of these hash functions.
//!
//! [`sha2`]: https://crates.io/crates/sha2
//!
//! # Examples
//!
//! Compute the SHA-256 hash of the Bitcoin genesis block at compile time:
//!
//! ```rust
//! # use sha2_const::Sha256;
//! const VERSION: u32 = 1;
//! const HASH_PREV_BLOCK: [u8; 32] = [0; 32];
//! const HASH_MERKLE_ROOT: [u8; 32] = [
//! 0x3b, 0xa3, 0xed, 0xfd, 0x7a, 0x7b, 0x12, 0xb2, 0x7a, 0xc7, 0x2c, 0x3e, 0x67, 0x76, 0x8f,
//! 0x61, 0x7f, 0xc8, 0x1b, 0xc3, 0x88, 0x8a, 0x51, 0x32, 0x3a, 0x9f, 0xb8, 0xaa, 0x4b, 0x1e,
//! 0x5e, 0x4a,
//! ];
//! const TIME: u32 = 1231006505;
//! const BITS: u32 = 0x1d00ffff;
//! const NONCE: u32 = 0x7c2bac1d;
//!
//! const BLOCK_HASH: [u8; 32] = Sha256::new()
//! .update(
//! &Sha256::new()
//! .update(&VERSION.to_le_bytes())
//! .update(&HASH_PREV_BLOCK)
//! .update(&HASH_MERKLE_ROOT)
//! .update(&TIME.to_le_bytes())
//! .update(&BITS.to_le_bytes())
//! .update(&NONCE.to_le_bytes())
//! .finalize(),
//! )
//! .finalize();
//!
//! assert_eq!(
//! hex::encode(&BLOCK_HASH[..]),
//! "6fe28c0ab6f1b372c1a6a246ae63f74f931e8365e15a089c68d6190000000000"
//! );
//! ```
#![feature(const_mut_refs)]
#![no_std]
mod constants;
mod sha;
mod util;
use constants::{H224, H256, H384, H512, H512_224, H512_256};
use util::memcpy;
macro_rules! sha {
(
$(#[$doc:meta])* $name:ident,
$size:literal,
$inner:ty,
$iv:ident
) => {
$(#[$doc])*
#[derive(Clone)]
pub struct $name {
inner: $inner,
}
impl $name {
/// The internal block size of the hash function.
pub const BLOCK_SIZE: usize = <$inner>::BLOCK_SIZE;
/// The digest size of the hash function.
pub const DIGEST_SIZE: usize = $size;
/// Construct a new instance.
pub const fn new() -> Self {
Self {
inner: <$inner>::new($iv),
}
}
/// Add input data to the hash context.
#[must_use]
pub const fn update(mut self, input: &[u8]) -> Self {
self.inner.update(&input);
self
}
/// Finalize the context and compute the digest.
#[must_use]
pub const fn finalize(self) -> [u8; Self::DIGEST_SIZE] {
let digest = self.inner.finalize();
let mut truncated = [0; Self::DIGEST_SIZE];
memcpy(&mut truncated, 0, &digest, 0, Self::DIGEST_SIZE);
truncated
}
}
};
}
sha!(
/// The SHA-224 hash function.
///
/// The SHA-256 algorithm with the SHA-224 initialization vector, truncated
/// to 224 bits.
///
/// # Examples
///
/// ```rust
/// # use sha2_const::Sha224;
/// const DIGEST: [u8; 28] = Sha224::new()
/// .update(b"The quick brown fox ")
/// .update(b"jumps over the lazy dog")
/// .finalize();
///
/// assert_eq!(
/// hex::encode(&DIGEST[..]),
/// "730e109bd7a8a32b1cb9d9a09aa2325d2430587ddbc0c38bad911525"
/// );
/// ```
Sha224,
28,
sha::Sha256,
H224
);
sha!(
/// The SHA-256 hash function.
///
/// # Examples
///
/// ```rust
/// # use sha2_const::Sha256;
/// const DIGEST: [u8; 32] = Sha256::new()
/// .update(b"The quick brown fox ")
/// .update(b"jumps over the lazy dog")
/// .finalize();
///
/// assert_eq!(
/// hex::encode(&DIGEST[..]),
/// "d7a8fbb307d7809469ca9abcb0082e4f8d5651e46d3cdb762d02d0bf37c9e592"
/// );
/// ```
Sha256,
32,
sha::Sha256,
H256
);
sha!(
/// The SHA-384 hash function.
///
/// The SHA-512 algorithm with the SHA-384 initialization vector, truncated
/// to 384 bits.
///
/// # Examples
///
/// ```rust
/// # use sha2_const::Sha384;
/// const DIGEST: [u8; 48] = Sha384::new()
/// .update(b"The quick brown fox ")
/// .update(b"jumps over the lazy dog")
/// .finalize();
///
/// assert_eq!(
/// hex::encode(&DIGEST[..]),
/// concat!(
/// "ca737f1014a48f4c0b6dd43cb177b0afd9e5169367544c49",
/// "4011e3317dbf9a509cb1e5dc1e85a941bbee3d7f2afbc9b1"
/// )
/// );
/// ```
Sha384,
48,
sha::Sha512,
H384
);
sha!(
/// The SHA-512 hash function.
///
/// # Examples
///
/// ```rust
/// # use sha2_const::Sha512;
/// const DIGEST: [u8; 64] = Sha512::new()
/// .update(b"The quick brown fox ")
/// .update(b"jumps over the lazy dog")
/// .finalize();
///
/// assert_eq!(
/// hex::encode(&DIGEST[..]),
/// concat!(
/// "07e547d9586f6a73f73fbac0435ed76951218fb7d0c8d788a309d785436bbb64",
/// "2e93a252a954f23912547d1e8a3b5ed6e1bfd7097821233fa0538f3db854fee6"
/// )
/// );
/// ```
Sha512,
64,
sha::Sha512,
H512
);
sha!(
/// The SHA-512/224 hash function.
///
/// The SHA-512 algorithm with the SHA-512/224 initialization vector,
/// truncated to 224 bits.
///
/// # Examples
///
/// ```rust
/// # use sha2_const::Sha512_224;
/// const DIGEST: [u8; 28] = Sha512_224::new()
/// .update(b"The quick brown fox ")
/// .update(b"jumps over the lazy dog")
/// .finalize();
///
/// assert_eq!(
/// hex::encode(&DIGEST[..]),
/// "944cd2847fb54558d4775db0485a50003111c8e5daa63fe722c6aa37"
/// );
/// ```
Sha512_224,
28,
sha::Sha512,
H512_224
);
sha!(
/// The SHA-512/256 hash function.
///
/// The SHA-512 algorithm with the SHA-512/256 initialization vector,
/// truncated to 256 bits.
///
/// # Examples
///
/// ```rust
/// # use sha2_const::Sha512_256;
/// const DIGEST: [u8; 32] = Sha512_256::new()
/// .update(b"The quick brown fox ")
/// .update(b"jumps over the lazy dog")
/// .finalize();
///
/// assert_eq!(
/// hex::encode(&DIGEST[..]),
/// "dd9d67b371519c339ed8dbd25af90e976a1eeefd4ad3d889005e532fc5bef04d"
/// );
/// ```
Sha512_256,
32,
sha::Sha512,
H512_256
);