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//! BLAKE2bp, a variant of BLAKE2b that uses SIMD more efficiently.
//!
//! The AVX2 implementation of BLAKE2bp is about twice as fast that of BLAKE2b.
//! However, note that it's a different hash function, and it gives a different
//! hash from BLAKE2b for the same input.
//!
//! # Example
//!
//! ```
//! use blake2b_simd::blake2bp;
//!
//! let hash = blake2bp::Params::new()
//! .hash_length(16)
//! .key(b"The Magic Words are Squeamish Ossifrage")
//! .to_state()
//! .update(b"foo")
//! .update(b"bar")
//! .update(b"baz")
//! .finalize();
//! assert_eq!("e69c7d2c42a5ac14948772231c68c552", &hash.to_hex());
//! ```
use crate::guts::{Finalize, Implementation, Job, LastNode, Stride};
use crate::many;
use crate::Count;
use crate::Hash;
use crate::Word;
use crate::BLOCKBYTES;
use crate::KEYBYTES;
use crate::OUTBYTES;
use core::cmp;
use core::fmt;
use core::mem::size_of;
#[cfg(feature = "std")]
use std;
pub(crate) const DEGREE: usize = 4;
/// Compute the BLAKE2bp hash of a slice of bytes all at once, using default
/// parameters.
///
/// # Example
///
/// ```
/// # use blake2b_simd::blake2bp::blake2bp;
/// let expected = "8ca9ccee7946afcb686fe7556628b5ba1bf9a691da37ca58cd049354d99f3704\
/// 2c007427e5f219b9ab5063707ec6823872dee413ee014b4d02f2ebb6abb5f643";
/// let hash = blake2bp(b"foo");
/// assert_eq!(expected, &hash.to_hex());
/// ```
pub fn blake2bp(input: &[u8]) -> Hash {
Params::new().hash(input)
}
/// A parameter builder for BLAKE2bp, just like the [`Params`](../struct.Params.html) type for
/// BLAKE2b.
///
/// This builder only supports configuring the hash length and a secret key. This matches the
/// options provided by the [reference
/// implementation](https://github.com/BLAKE2/BLAKE2/blob/320c325437539ae91091ce62efec1913cd8093c2/ref/blake2.h#L162-L165).
///
/// # Example
///
/// ```
/// use blake2b_simd::blake2bp;
/// let mut state = blake2bp::Params::new().hash_length(32).to_state();
/// ```
#[derive(Clone)]
pub struct Params {
hash_length: u8,
key_length: u8,
key: [u8; KEYBYTES],
implementation: Implementation,
}
impl Params {
/// Equivalent to `Params::default()`.
pub fn new() -> Self {
Self {
hash_length: OUTBYTES as u8,
key_length: 0,
key: [0; KEYBYTES],
implementation: Implementation::detect(),
}
}
fn to_words(&self) -> ([[Word; 8]; DEGREE], [Word; 8]) {
let mut base_params = crate::Params::new();
base_params
.hash_length(self.hash_length as usize)
.key(&self.key[..self.key_length as usize])
.fanout(DEGREE as u8)
.max_depth(2)
.max_leaf_length(0)
// Note that inner_hash_length is always OUTBYTES, regardless of the hash_length
// parameter. This isn't documented in the spec, but it matches the behavior of the
// reference implementation: https://github.com/BLAKE2/BLAKE2/blob/320c325437539ae91091ce62efec1913cd8093c2/ref/blake2bp-ref.c#L55
.inner_hash_length(OUTBYTES);
let leaf_words = |worker_index| {
base_params
.clone()
.node_offset(worker_index)
.node_depth(0)
// Note that setting the last_node flag here has no effect,
// because it isn't included in the state words.
.to_words()
};
let leaf_words = [leaf_words(0), leaf_words(1), leaf_words(2), leaf_words(3)];
let root_words = base_params
.clone()
.node_offset(0)
.node_depth(1)
// Note that setting the last_node flag here has no effect, because
// it isn't included in the state words. Also note that because
// we're only preserving its state words, the root node won't hash
// any key bytes.
.to_words();
(leaf_words, root_words)
}
/// Hash an input all at once with these parameters.
pub fn hash(&self, input: &[u8]) -> Hash {
// If there's a key, just fall back to using the State.
if self.key_length > 0 {
return self.to_state().update(input).finalize();
}
let (mut leaf_words, mut root_words) = self.to_words();
// Hash each leaf in parallel.
let jobs = leaf_words.iter_mut().enumerate().map(|(i, words)| {
let input_start = cmp::min(input.len(), i * BLOCKBYTES);
Job {
input: &input[input_start..],
words,
count: 0,
last_node: if i == DEGREE - 1 {
LastNode::Yes
} else {
LastNode::No
},
}
});
many::compress_many(jobs, self.implementation, Finalize::Yes, Stride::Parallel);
// Hash each leaf into the root.
finalize_root_words(
&leaf_words,
&mut root_words,
self.hash_length,
self.implementation,
)
}
/// Construct a BLAKE2bp `State` object based on these parameters.
pub fn to_state(&self) -> State {
State::with_params(self)
}
/// Set the length of the final hash, from 1 to `OUTBYTES` (64). Apart from controlling the
/// length of the final `Hash`, this is also associated data, and changing it will result in a
/// totally different hash.
pub fn hash_length(&mut self, length: usize) -> &mut Self {
assert!(
1 <= length && length <= OUTBYTES,
"Bad hash length: {}",
length
);
self.hash_length = length as u8;
self
}
/// Use a secret key, so that BLAKE2bp acts as a MAC. The maximum key length is `KEYBYTES`
/// (64). An empty key is equivalent to having no key at all.
pub fn key(&mut self, key: &[u8]) -> &mut Self {
assert!(key.len() <= KEYBYTES, "Bad key length: {}", key.len());
self.key_length = key.len() as u8;
self.key = [0; KEYBYTES];
self.key[..key.len()].copy_from_slice(key);
self
}
}
impl Default for Params {
fn default() -> Self {
Self::new()
}
}
impl fmt::Debug for Params {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(
f,
"Params {{ hash_length: {}, key_length: {} }}",
self.hash_length,
// NB: Don't print the key itself. Debug shouldn't leak secrets.
self.key_length,
)
}
}
/// An incremental hasher for BLAKE2bp, just like the [`State`](../struct.State.html) type for
/// BLAKE2b.
///
/// # Example
///
/// ```
/// use blake2b_simd::blake2bp;
///
/// let mut state = blake2bp::State::new();
/// state.update(b"foo");
/// state.update(b"bar");
/// let hash = state.finalize();
///
/// let expected = "e654427b6ef02949471712263e59071abbb6aa94855674c1daeed6cfaf127c33\
/// dfa3205f7f7f71e4f0673d25fa82a368488911f446bccd323af3ab03f53e56e5";
/// assert_eq!(expected, &hash.to_hex());
/// ```
#[derive(Clone)]
pub struct State {
leaf_words: [[Word; 8]; DEGREE],
root_words: [Word; 8],
// Note that this buffer is twice as large as what compress4 needs. That guarantees that we
// have enough input when we compress to know we don't need to finalize any of the leaves.
buf: [u8; 2 * DEGREE * BLOCKBYTES],
buf_len: u16,
// Note that this is the *per-leaf* count.
count: Count,
hash_length: u8,
implementation: Implementation,
is_keyed: bool,
}
impl State {
/// Equivalent to `State::default()` or `Params::default().to_state()`.
pub fn new() -> Self {
Self::with_params(&Params::default())
}
fn with_params(params: &Params) -> Self {
let (leaf_words, root_words) = params.to_words();
// If a key is set, initalize the buffer to contain the key bytes. Note
// that only the leaves hash key bytes. The root doesn't, even though
// the key length it still set in its parameters. Again this isn't
// documented in the spec, but it matches the behavior of the reference
// implementation:
// https://github.com/BLAKE2/BLAKE2/blob/320c325437539ae91091ce62efec1913cd8093c2/ref/blake2bp-ref.c#L128
// This particular behavior (though not the inner hash length behavior
// above) is also corroborated by the official test vectors; see
// tests/vector_tests.rs.
let mut buf = [0; 2 * DEGREE * BLOCKBYTES];
let mut buf_len = 0;
if params.key_length > 0 {
for i in 0..DEGREE {
let keybytes = ¶ms.key[..params.key_length as usize];
buf[i * BLOCKBYTES..][..keybytes.len()].copy_from_slice(keybytes);
buf_len = BLOCKBYTES * DEGREE;
}
}
Self {
leaf_words,
root_words,
buf,
buf_len: buf_len as u16,
count: 0, // count gets updated in self.compress()
hash_length: params.hash_length,
implementation: params.implementation,
is_keyed: params.key_length > 0,
}
}
fn fill_buf(&mut self, input: &mut &[u8]) {
let take = cmp::min(self.buf.len() - self.buf_len as usize, input.len());
self.buf[self.buf_len as usize..][..take].copy_from_slice(&input[..take]);
self.buf_len += take as u16;
*input = &input[take..];
}
fn compress_to_leaves(
leaves: &mut [[Word; 8]; DEGREE],
input: &[u8],
count: &mut Count,
implementation: Implementation,
) {
// Input is assumed to be an even number of blocks for each leaf. Since
// we're not finilizing, debug asserts will fire otherwise.
let jobs = leaves.iter_mut().enumerate().map(|(i, words)| {
Job {
input: &input[i * BLOCKBYTES..],
words,
count: *count,
last_node: LastNode::No, // irrelevant when not finalizing
}
});
many::compress_many(jobs, implementation, Finalize::No, Stride::Parallel);
// Note that count is the bytes input *per-leaf*.
*count = count.wrapping_add((input.len() / DEGREE) as Count);
}
/// Add input to the hash. You can call `update` any number of times.
pub fn update(&mut self, mut input: &[u8]) -> &mut Self {
// If we have a partial buffer, try to complete it. If we complete it and there's more
// input waiting, we need to compress to make more room. However, because we need to be
// sure that *none* of the leaves would need to be finalized as part of this round of
// compression, we need to buffer more than we would for BLAKE2b.
if self.buf_len > 0 {
self.fill_buf(&mut input);
// The buffer is large enough for two compressions. If we've filled
// the buffer and there's still more input coming, then we have to
// do at least one compression. If there's enough input still
// coming that all the leaves are guaranteed to get more, do both
// compressions in the buffer. Otherwise, do just one and shift the
// back half of the buffer to the front.
if !input.is_empty() {
if input.len() > (DEGREE - 1) * BLOCKBYTES {
// Enough input coming to do both compressions.
Self::compress_to_leaves(
&mut self.leaf_words,
&self.buf,
&mut self.count,
self.implementation,
);
self.buf_len = 0;
} else {
// Only enough input coming for one compression.
Self::compress_to_leaves(
&mut self.leaf_words,
&self.buf[..DEGREE * BLOCKBYTES],
&mut self.count,
self.implementation,
);
self.buf_len = (DEGREE * BLOCKBYTES) as u16;
let (buf_front, buf_back) = self.buf.split_at_mut(DEGREE * BLOCKBYTES);
buf_front.copy_from_slice(buf_back);
}
}
}
// Now we directly compress as much input as possible, without copying
// it into the buffer. We need to make sure we buffer at least one byte
// for each of the leaves, so that we know we don't need to finalize
// them.
let needed_tail = (DEGREE - 1) * BLOCKBYTES + 1;
let mut bulk_bytes = input.len().saturating_sub(needed_tail);
bulk_bytes -= bulk_bytes % (DEGREE * BLOCKBYTES);
if bulk_bytes > 0 {
Self::compress_to_leaves(
&mut self.leaf_words,
&input[..bulk_bytes],
&mut self.count,
self.implementation,
);
input = &input[bulk_bytes..];
}
// Buffer any remaining input, to be either compressed or finalized in
// a subsequent call.
self.fill_buf(&mut input);
debug_assert_eq!(0, input.len());
self
}
/// Finalize the state and return a `Hash`. This method is idempotent, and calling it multiple
/// times will give the same result. It's also possible to `update` with more input in between.
pub fn finalize(&self) -> Hash {
// Hash whatever's remaining in the buffer and finalize the leaves.
let buf_len = self.buf_len as usize;
let mut leaves_copy = self.leaf_words;
let jobs = leaves_copy
.iter_mut()
.enumerate()
.map(|(leaf_index, leaf_words)| {
let input = &self.buf[cmp::min(leaf_index * BLOCKBYTES, buf_len)..buf_len];
Job {
input,
words: leaf_words,
count: self.count,
last_node: if leaf_index == DEGREE - 1 {
LastNode::Yes
} else {
LastNode::No
},
}
});
many::compress_many(jobs, self.implementation, Finalize::Yes, Stride::Parallel);
// Concatenate each leaf into the root and hash that.
let mut root_words_copy = self.root_words;
finalize_root_words(
&leaves_copy,
&mut root_words_copy,
self.hash_length,
self.implementation,
)
}
/// Return the total number of bytes input so far.
///
/// Note that `count` doesn't include the bytes of the key block, if any.
/// It's exactly the total number of input bytes fed to `update`.
pub fn count(&self) -> Count {
// Remember that self.count is *per-leaf*.
let mut ret = self
.count
.wrapping_mul(DEGREE as Count)
.wrapping_add(self.buf_len as Count);
if self.is_keyed {
ret -= (DEGREE * BLOCKBYTES) as Count;
}
ret
}
}
#[cfg(feature = "std")]
impl std::io::Write for State {
fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
self.update(buf);
Ok(buf.len())
}
fn flush(&mut self) -> std::io::Result<()> {
Ok(())
}
}
impl fmt::Debug for State {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(
f,
"State {{ count: {}, hash_length: {} }}",
self.count(),
self.hash_length,
)
}
}
impl Default for State {
fn default() -> Self {
Self::with_params(&Params::default())
}
}
// Compress each of the four finalized hashes into the root words as input,
// using two compressions. Note that even if a future version of this
// implementation supports the hash_length parameter and sets it as associated
// data for all nodes, this step must still use the untruncated output of each
// leaf. Note also that, as mentioned above, the root node doesn't hash any key
// bytes.
fn finalize_root_words(
leaf_words: &[[Word; 8]; DEGREE],
root_words: &mut [Word; 8],
hash_length: u8,
imp: Implementation,
) -> Hash {
debug_assert_eq!(OUTBYTES, 8 * size_of::<Word>());
let mut block = [0; DEGREE * OUTBYTES];
for (word, chunk) in leaf_words
.iter()
.flat_map(|words| words.iter())
.zip(block.chunks_exact_mut(size_of::<Word>()))
{
chunk.copy_from_slice(&word.to_le_bytes());
}
imp.compress1_loop(
&block,
root_words,
0,
LastNode::Yes,
Finalize::Yes,
Stride::Serial,
);
Hash {
bytes: crate::state_words_to_bytes(&root_words),
len: hash_length,
}
}
pub(crate) fn force_portable(params: &mut Params) {
params.implementation = Implementation::portable();
}
#[cfg(test)]
pub(crate) mod test {
use super::*;
use crate::paint_test_input;
// This is a simple reference implementation without the complicated buffering or parameter
// support of the real implementation. We need this because the official test vectors don't
// include any inputs large enough to exercise all the branches in the buffering logic.
fn blake2bp_reference(input: &[u8]) -> Hash {
let mut leaves = arrayvec::ArrayVec::<_, DEGREE>::new();
for leaf_index in 0..DEGREE {
leaves.push(
crate::Params::new()
.fanout(DEGREE as u8)
.max_depth(2)
.node_offset(leaf_index as u64)
.inner_hash_length(OUTBYTES)
.to_state(),
);
}
leaves[DEGREE - 1].set_last_node(true);
for (i, chunk) in input.chunks(BLOCKBYTES).enumerate() {
leaves[i % DEGREE].update(chunk);
}
let mut root = crate::Params::new()
.fanout(DEGREE as u8)
.max_depth(2)
.node_depth(1)
.inner_hash_length(OUTBYTES)
.last_node(true)
.to_state();
for leaf in &mut leaves {
root.update(leaf.finalize().as_bytes());
}
root.finalize()
}
#[test]
fn test_against_reference() {
let mut buf = [0; 21 * BLOCKBYTES];
paint_test_input(&mut buf);
// - 8 blocks is just enought to fill the double buffer.
// - 9 blocks triggers the "perform one compression on the double buffer" case.
// - 11 blocks is the largest input where only one compression may be performed, on the
// first half of the buffer, because there's not enough input to avoid needing to
// finalize the second half.
// - 12 blocks triggers the "perform both compressions in the double buffer" case.
// - 15 blocks is the largest input where, after compressing 8 blocks from the buffer,
// there's not enough input to hash directly from memory.
// - 16 blocks triggers "after emptying the buffer, hash directly from memory".
for num_blocks in 0..=20 {
for &extra in &[0, 1, BLOCKBYTES - 1] {
for &portable in &[false, true] {
// eprintln!("\ncase -----");
// dbg!(num_blocks);
// dbg!(extra);
// dbg!(portable);
// First hash the input all at once, as a sanity check.
let mut params = Params::new();
if portable {
force_portable(&mut params);
}
let input = &buf[..num_blocks * BLOCKBYTES + extra];
let expected = blake2bp_reference(&input);
let mut state = params.to_state();
let found = state.update(input).finalize();
assert_eq!(expected, found);
// Then, do it again, but buffer 1 byte of input first. That causes the buffering
// branch to trigger.
let mut state = params.to_state();
let maybe_one = cmp::min(1, input.len());
state.update(&input[..maybe_one]);
assert_eq!(maybe_one as Count, state.count());
// Do a throwaway finalize here to check for idempotency.
state.finalize();
state.update(&input[maybe_one..]);
assert_eq!(input.len() as Count, state.count());
let found = state.finalize();
assert_eq!(expected, found);
// Finally, do it again with the all-at-once interface.
assert_eq!(expected, blake2bp(input));
}
}
}
}
}