// SPDX-License-Identifier: CC0-1.0 //! SipHash 2-4 implementation. //! use core::ops::Index; use core::slice::SliceIndex; use core::{cmp, mem, ptr, str}; use crate::{FromSliceError, Hash as _, HashEngine as _}; crate::internal_macros::hash_type! { 64, false, "Output of the SipHash24 hash function.", "crate::util::json_hex_string::len_8" } #[cfg(not(hashes_fuzz))] fn from_engine(e: HashEngine) -> Hash { Hash::from_u64(Hash::from_engine_to_u64(e)) } #[cfg(hashes_fuzz)] fn from_engine(e: HashEngine) -> Hash { let state = e.midstate(); Hash::from_u64(state.v0 ^ state.v1 ^ state.v2 ^ state.v3) } macro_rules! compress { ($state:expr) => {{ compress!($state.v0, $state.v1, $state.v2, $state.v3) }}; ($v0:expr, $v1:expr, $v2:expr, $v3:expr) => {{ $v0 = $v0.wrapping_add($v1); $v1 = $v1.rotate_left(13); $v1 ^= $v0; $v0 = $v0.rotate_left(32); $v2 = $v2.wrapping_add($v3); $v3 = $v3.rotate_left(16); $v3 ^= $v2; $v0 = $v0.wrapping_add($v3); $v3 = $v3.rotate_left(21); $v3 ^= $v0; $v2 = $v2.wrapping_add($v1); $v1 = $v1.rotate_left(17); $v1 ^= $v2; $v2 = $v2.rotate_left(32); }}; } /// Load an integer of the desired type from a byte stream, in LE order. Uses /// `copy_nonoverlapping` to let the compiler generate the most efficient way /// to load it from a possibly unaligned address. /// /// Unsafe because: unchecked indexing at `i..i+size_of(int_ty)`. macro_rules! load_int_le { ($buf:expr, $i:expr, $int_ty:ident) => {{ debug_assert!($i + mem::size_of::<$int_ty>() <= $buf.len()); let mut data = 0 as $int_ty; ptr::copy_nonoverlapping( $buf.get_unchecked($i), &mut data as *mut _ as *mut u8, mem::size_of::<$int_ty>(), ); data.to_le() }}; } /// Internal state of the [`HashEngine`]. #[derive(Debug, Clone)] pub struct State { // v0, v2 and v1, v3 show up in pairs in the algorithm, // and simd implementations of SipHash will use vectors // of v02 and v13. By placing them in this order in the struct, // the compiler can pick up on just a few simd optimizations by itself. v0: u64, v2: u64, v1: u64, v3: u64, } /// Engine to compute the SipHash24 hash function. #[derive(Debug, Clone)] pub struct HashEngine { k0: u64, k1: u64, length: usize, // how many bytes we've processed state: State, // hash State tail: u64, // unprocessed bytes le ntail: usize, // how many bytes in tail are valid } impl HashEngine { /// Creates a new SipHash24 engine with keys. pub fn with_keys(k0: u64, k1: u64) -> HashEngine { HashEngine { k0, k1, length: 0, state: State { v0: k0 ^ 0x736f6d6570736575, v1: k1 ^ 0x646f72616e646f6d, v2: k0 ^ 0x6c7967656e657261, v3: k1 ^ 0x7465646279746573, }, tail: 0, ntail: 0, } } /// Creates a new SipHash24 engine. pub fn new() -> HashEngine { HashEngine::with_keys(0, 0) } /// Retrieves the keys of this engine. pub fn keys(&self) -> (u64, u64) { (self.k0, self.k1) } #[inline] fn c_rounds(state: &mut State) { compress!(state); compress!(state); } #[inline] fn d_rounds(state: &mut State) { compress!(state); compress!(state); compress!(state); compress!(state); } } impl Default for HashEngine { fn default() -> Self { HashEngine::new() } } impl crate::HashEngine for HashEngine { type MidState = State; fn midstate(&self) -> State { self.state.clone() } const BLOCK_SIZE: usize = 8; #[inline] fn input(&mut self, msg: &[u8]) { let length = msg.len(); self.length += length; let mut needed = 0; if self.ntail != 0 { needed = 8 - self.ntail; self.tail |= unsafe { u8to64_le(msg, 0, cmp::min(length, needed)) } << (8 * self.ntail); if length < needed { self.ntail += length; return; } else { self.state.v3 ^= self.tail; HashEngine::c_rounds(&mut self.state); self.state.v0 ^= self.tail; self.ntail = 0; } } // Buffered tail is now flushed, process new input. let len = length - needed; let left = len & 0x7; let mut i = needed; while i < len - left { let mi = unsafe { load_int_le!(msg, i, u64) }; self.state.v3 ^= mi; HashEngine::c_rounds(&mut self.state); self.state.v0 ^= mi; i += 8; } self.tail = unsafe { u8to64_le(msg, i, left) }; self.ntail = left; } fn n_bytes_hashed(&self) -> usize { self.length } } impl Hash { /// Hashes the given data with an engine with the provided keys. pub fn hash_with_keys(k0: u64, k1: u64, data: &[u8]) -> Hash { let mut engine = HashEngine::with_keys(k0, k1); engine.input(data); Hash::from_engine(engine) } /// Hashes the given data directly to u64 with an engine with the provided keys. pub fn hash_to_u64_with_keys(k0: u64, k1: u64, data: &[u8]) -> u64 { let mut engine = HashEngine::with_keys(k0, k1); engine.input(data); Hash::from_engine_to_u64(engine) } /// Produces a hash as `u64` from the current state of a given engine. #[inline] pub fn from_engine_to_u64(e: HashEngine) -> u64 { let mut state = e.state; let b: u64 = ((e.length as u64 & 0xff) << 56) | e.tail; state.v3 ^= b; HashEngine::c_rounds(&mut state); state.v0 ^= b; state.v2 ^= 0xff; HashEngine::d_rounds(&mut state); state.v0 ^ state.v1 ^ state.v2 ^ state.v3 } /// Returns the (little endian) 64-bit integer representation of the hash value. pub fn as_u64(&self) -> u64 { u64::from_le_bytes(self.0) } /// Creates a hash from its (little endian) 64-bit integer representation. pub fn from_u64(hash: u64) -> Hash { Hash(hash.to_le_bytes()) } } /// Load an u64 using up to 7 bytes of a byte slice. /// /// Unsafe because: unchecked indexing at `start..start+len`. #[inline] unsafe fn u8to64_le(buf: &[u8], start: usize, len: usize) -> u64 { debug_assert!(len < 8); let mut i = 0; // current byte index (from LSB) in the output u64 let mut out = 0; if i + 3 < len { out = u64::from(load_int_le!(buf, start + i, u32)); i += 4; } if i + 1 < len { out |= u64::from(load_int_le!(buf, start + i, u16)) << (i * 8); i += 2 } if i < len { out |= u64::from(*buf.get_unchecked(start + i)) << (i * 8); i += 1; } debug_assert_eq!(i, len); out } #[cfg(test)] mod tests { use super::*; #[test] fn test_siphash_2_4() { #[rustfmt::skip] let vecs: [[u8; 8]; 64] = [ [0x31, 0x0e, 0x0e, 0xdd, 0x47, 0xdb, 0x6f, 0x72], [0xfd, 0x67, 0xdc, 0x93, 0xc5, 0x39, 0xf8, 0x74], [0x5a, 0x4f, 0xa9, 0xd9, 0x09, 0x80, 0x6c, 0x0d], [0x2d, 0x7e, 0xfb, 0xd7, 0x96, 0x66, 0x67, 0x85], [0xb7, 0x87, 0x71, 0x27, 0xe0, 0x94, 0x27, 0xcf], [0x8d, 0xa6, 0x99, 0xcd, 0x64, 0x55, 0x76, 0x18], [0xce, 0xe3, 0xfe, 0x58, 0x6e, 0x46, 0xc9, 0xcb], [0x37, 0xd1, 0x01, 0x8b, 0xf5, 0x00, 0x02, 0xab], [0x62, 0x24, 0x93, 0x9a, 0x79, 0xf5, 0xf5, 0x93], [0xb0, 0xe4, 0xa9, 0x0b, 0xdf, 0x82, 0x00, 0x9e], [0xf3, 0xb9, 0xdd, 0x94, 0xc5, 0xbb, 0x5d, 0x7a], [0xa7, 0xad, 0x6b, 0x22, 0x46, 0x2f, 0xb3, 0xf4], [0xfb, 0xe5, 0x0e, 0x86, 0xbc, 0x8f, 0x1e, 0x75], [0x90, 0x3d, 0x84, 0xc0, 0x27, 0x56, 0xea, 0x14], [0xee, 0xf2, 0x7a, 0x8e, 0x90, 0xca, 0x23, 0xf7], [0xe5, 0x45, 0xbe, 0x49, 0x61, 0xca, 0x29, 0xa1], [0xdb, 0x9b, 0xc2, 0x57, 0x7f, 0xcc, 0x2a, 0x3f], [0x94, 0x47, 0xbe, 0x2c, 0xf5, 0xe9, 0x9a, 0x69], [0x9c, 0xd3, 0x8d, 0x96, 0xf0, 0xb3, 0xc1, 0x4b], [0xbd, 0x61, 0x79, 0xa7, 0x1d, 0xc9, 0x6d, 0xbb], [0x98, 0xee, 0xa2, 0x1a, 0xf2, 0x5c, 0xd6, 0xbe], [0xc7, 0x67, 0x3b, 0x2e, 0xb0, 0xcb, 0xf2, 0xd0], [0x88, 0x3e, 0xa3, 0xe3, 0x95, 0x67, 0x53, 0x93], [0xc8, 0xce, 0x5c, 0xcd, 0x8c, 0x03, 0x0c, 0xa8], [0x94, 0xaf, 0x49, 0xf6, 0xc6, 0x50, 0xad, 0xb8], [0xea, 0xb8, 0x85, 0x8a, 0xde, 0x92, 0xe1, 0xbc], [0xf3, 0x15, 0xbb, 0x5b, 0xb8, 0x35, 0xd8, 0x17], [0xad, 0xcf, 0x6b, 0x07, 0x63, 0x61, 0x2e, 0x2f], [0xa5, 0xc9, 0x1d, 0xa7, 0xac, 0xaa, 0x4d, 0xde], [0x71, 0x65, 0x95, 0x87, 0x66, 0x50, 0xa2, 0xa6], [0x28, 0xef, 0x49, 0x5c, 0x53, 0xa3, 0x87, 0xad], [0x42, 0xc3, 0x41, 0xd8, 0xfa, 0x92, 0xd8, 0x32], [0xce, 0x7c, 0xf2, 0x72, 0x2f, 0x51, 0x27, 0x71], [0xe3, 0x78, 0x59, 0xf9, 0x46, 0x23, 0xf3, 0xa7], [0x38, 0x12, 0x05, 0xbb, 0x1a, 0xb0, 0xe0, 0x12], [0xae, 0x97, 0xa1, 0x0f, 0xd4, 0x34, 0xe0, 0x15], [0xb4, 0xa3, 0x15, 0x08, 0xbe, 0xff, 0x4d, 0x31], [0x81, 0x39, 0x62, 0x29, 0xf0, 0x90, 0x79, 0x02], [0x4d, 0x0c, 0xf4, 0x9e, 0xe5, 0xd4, 0xdc, 0xca], [0x5c, 0x73, 0x33, 0x6a, 0x76, 0xd8, 0xbf, 0x9a], [0xd0, 0xa7, 0x04, 0x53, 0x6b, 0xa9, 0x3e, 0x0e], [0x92, 0x59, 0x58, 0xfc, 0xd6, 0x42, 0x0c, 0xad], [0xa9, 0x15, 0xc2, 0x9b, 0xc8, 0x06, 0x73, 0x18], [0x95, 0x2b, 0x79, 0xf3, 0xbc, 0x0a, 0xa6, 0xd4], [0xf2, 0x1d, 0xf2, 0xe4, 0x1d, 0x45, 0x35, 0xf9], [0x87, 0x57, 0x75, 0x19, 0x04, 0x8f, 0x53, 0xa9], [0x10, 0xa5, 0x6c, 0xf5, 0xdf, 0xcd, 0x9a, 0xdb], [0xeb, 0x75, 0x09, 0x5c, 0xcd, 0x98, 0x6c, 0xd0], [0x51, 0xa9, 0xcb, 0x9e, 0xcb, 0xa3, 0x12, 0xe6], [0x96, 0xaf, 0xad, 0xfc, 0x2c, 0xe6, 0x66, 0xc7], [0x72, 0xfe, 0x52, 0x97, 0x5a, 0x43, 0x64, 0xee], [0x5a, 0x16, 0x45, 0xb2, 0x76, 0xd5, 0x92, 0xa1], [0xb2, 0x74, 0xcb, 0x8e, 0xbf, 0x87, 0x87, 0x0a], [0x6f, 0x9b, 0xb4, 0x20, 0x3d, 0xe7, 0xb3, 0x81], [0xea, 0xec, 0xb2, 0xa3, 0x0b, 0x22, 0xa8, 0x7f], [0x99, 0x24, 0xa4, 0x3c, 0xc1, 0x31, 0x57, 0x24], [0xbd, 0x83, 0x8d, 0x3a, 0xaf, 0xbf, 0x8d, 0xb7], [0x0b, 0x1a, 0x2a, 0x32, 0x65, 0xd5, 0x1a, 0xea], [0x13, 0x50, 0x79, 0xa3, 0x23, 0x1c, 0xe6, 0x60], [0x93, 0x2b, 0x28, 0x46, 0xe4, 0xd7, 0x06, 0x66], [0xe1, 0x91, 0x5f, 0x5c, 0xb1, 0xec, 0xa4, 0x6c], [0xf3, 0x25, 0x96, 0x5c, 0xa1, 0x6d, 0x62, 0x9f], [0x57, 0x5f, 0xf2, 0x8e, 0x60, 0x38, 0x1b, 0xe5], [0x72, 0x45, 0x06, 0xeb, 0x4c, 0x32, 0x8a, 0x95], ]; let k0 = 0x_07_06_05_04_03_02_01_00; let k1 = 0x_0f_0e_0d_0c_0b_0a_09_08; let mut vin = [0u8; 64]; let mut state_inc = HashEngine::with_keys(k0, k1); for i in 0..64 { vin[i] = i as u8; let vec = Hash::from_slice(&vecs[i][..]).unwrap(); let out = Hash::hash_with_keys(k0, k1, &vin[0..i]); assert_eq!(vec, out, "vec #{}", i); let inc = Hash::from_engine(state_inc.clone()); assert_eq!(vec, inc, "vec #{}", i); state_inc.input(&[i as u8]); } } } #[cfg(bench)] mod benches { use test::Bencher; use crate::{siphash24, Hash, HashEngine}; #[bench] pub fn siphash24_1ki(bh: &mut Bencher) { let mut engine = siphash24::Hash::engine(); let bytes = [1u8; 1024]; bh.iter(|| { engine.input(&bytes); }); bh.bytes = bytes.len() as u64; } #[bench] pub fn siphash24_64ki(bh: &mut Bencher) { let mut engine = siphash24::Hash::engine(); let bytes = [1u8; 65536]; bh.iter(|| { engine.input(&bytes); }); bh.bytes = bytes.len() as u64; } #[bench] pub fn siphash24_1ki_hash(bh: &mut Bencher) { let k0 = 0x_07_06_05_04_03_02_01_00; let k1 = 0x_0f_0e_0d_0c_0b_0a_09_08; let bytes = [1u8; 1024]; bh.iter(|| { let _ = siphash24::Hash::hash_with_keys(k0, k1, &bytes); }); bh.bytes = bytes.len() as u64; } #[bench] pub fn siphash24_1ki_hash_u64(bh: &mut Bencher) { let k0 = 0x_07_06_05_04_03_02_01_00; let k1 = 0x_0f_0e_0d_0c_0b_0a_09_08; let bytes = [1u8; 1024]; bh.iter(|| { let _ = siphash24::Hash::hash_to_u64_with_keys(k0, k1, &bytes); }); bh.bytes = bytes.len() as u64; } }