Import rand_chacha-0.2.2 am: 79677650b9 am: d3080fd188
Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/rand_chacha/+/1357988
Change-Id: Ic6c06a3217ecaa6e15ccfa1bd13ad9c1a675a303
diff --git a/.cargo_vcs_info.json b/.cargo_vcs_info.json
new file mode 100644
index 0000000..0739f24
--- /dev/null
+++ b/.cargo_vcs_info.json
@@ -0,0 +1,5 @@
+{
+ "git": {
+ "sha1": "e2112c4404c61d3850c0e91f48114db5daf06569"
+ }
+}
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..1273895
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,22 @@
+# Changelog
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [0.2.2] - 2020-03-09
+- Integrate `c2-chacha`, reducing dependency count (#931)
+- Add CryptoRng to ChaChaXCore (#944)
+
+## [0.2.1] - 2019-07-22
+- Force enable the `simd` feature of `c2-chacha` (#845)
+
+## [0.2.0] - 2019-06-06
+- Rewrite based on the much faster `c2-chacha` crate (#789)
+
+## [0.1.1] - 2019-01-04
+- Disable `i128` and `u128` if the `target_os` is `emscripten` (#671: work-around Emscripten limitation)
+- Update readme and doc links
+
+## [0.1.0] - 2018-10-17
+- Pulled out of the Rand crate
diff --git a/COPYRIGHT b/COPYRIGHT
new file mode 100644
index 0000000..468d907
--- /dev/null
+++ b/COPYRIGHT
@@ -0,0 +1,12 @@
+Copyrights in the Rand project are retained by their contributors. No
+copyright assignment is required to contribute to the Rand project.
+
+For full authorship information, see the version control history.
+
+Except as otherwise noted (below and/or in individual files), Rand is
+licensed under the Apache License, Version 2.0 <LICENSE-APACHE> or
+<http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+<LICENSE-MIT> or <http://opensource.org/licenses/MIT>, at your option.
+
+The Rand project includes code from the Rust project
+published under these same licenses.
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..dea94e9
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,42 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies
+#
+# If you believe there's an error in this file please file an
+# issue against the rust-lang/cargo repository. If you're
+# editing this file be aware that the upstream Cargo.toml
+# will likely look very different (and much more reasonable)
+
+[package]
+edition = "2018"
+name = "rand_chacha"
+version = "0.2.2"
+authors = ["The Rand Project Developers", "The Rust Project Developers", "The CryptoCorrosion Contributors"]
+description = "ChaCha random number generator\n"
+homepage = "https://crates.io/crates/rand_chacha"
+documentation = "https://rust-random.github.io/rand/rand_chacha/"
+readme = "README.md"
+keywords = ["random", "rng", "chacha"]
+categories = ["algorithms", "no-std"]
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/rust-random/rand"
+[dependencies.ppv-lite86]
+version = "0.2.6"
+features = ["simd"]
+default-features = false
+
+[dependencies.rand_core]
+version = "0.5"
+
+[features]
+default = ["std", "simd"]
+simd = []
+std = ["ppv-lite86/std"]
+[badges.appveyor]
+repository = "rust-random/rand"
+
+[badges.travis-ci]
+repository = "rust-random/rand"
diff --git a/Cargo.toml.orig b/Cargo.toml.orig
new file mode 100644
index 0000000..601fef9
--- /dev/null
+++ b/Cargo.toml.orig
@@ -0,0 +1,28 @@
+[package]
+name = "rand_chacha"
+version = "0.2.2"
+authors = ["The Rand Project Developers", "The Rust Project Developers", "The CryptoCorrosion Contributors"]
+license = "MIT OR Apache-2.0"
+readme = "README.md"
+repository = "https://github.com/rust-random/rand"
+documentation = "https://rust-random.github.io/rand/rand_chacha/"
+homepage = "https://crates.io/crates/rand_chacha"
+description = """
+ChaCha random number generator
+"""
+keywords = ["random", "rng", "chacha"]
+categories = ["algorithms", "no-std"]
+edition = "2018"
+
+[badges]
+travis-ci = { repository = "rust-random/rand" }
+appveyor = { repository = "rust-random/rand" }
+
+[dependencies]
+rand_core = { path = "../rand_core", version = "0.5" }
+ppv-lite86 = { version = "0.2.6", default-features = false, features = ["simd"] }
+
+[features]
+default = ["std", "simd"]
+std = ["ppv-lite86/std"]
+simd = [] # deprecated
diff --git a/LICENSE-APACHE b/LICENSE-APACHE
new file mode 100644
index 0000000..17d7468
--- /dev/null
+++ b/LICENSE-APACHE
@@ -0,0 +1,201 @@
+ Apache License
+ Version 2.0, January 2004
+ https://www.apache.org/licenses/
+
+TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+1. Definitions.
+
+ "License" shall mean the terms and conditions for use, reproduction,
+ and distribution as defined by Sections 1 through 9 of this document.
+
+ "Licensor" shall mean the copyright owner or entity authorized by
+ the copyright owner that is granting the License.
+
+ "Legal Entity" shall mean the union of the acting entity and all
+ other entities that control, are controlled by, or are under common
+ control with that entity. For the purposes of this definition,
+ "control" means (i) the power, direct or indirect, to cause the
+ direction or management of such entity, whether by contract or
+ otherwise, or (ii) ownership of fifty percent (50%) or more of the
+ outstanding shares, or (iii) beneficial ownership of such entity.
+
+ "You" (or "Your") shall mean an individual or Legal Entity
+ exercising permissions granted by this License.
+
+ "Source" form shall mean the preferred form for making modifications,
+ including but not limited to software source code, documentation
+ source, and configuration files.
+
+ "Object" form shall mean any form resulting from mechanical
+ transformation or translation of a Source form, including but
+ not limited to compiled object code, generated documentation,
+ and conversions to other media types.
+
+ "Work" shall mean the work of authorship, whether in Source or
+ Object form, made available under the License, as indicated by a
+ copyright notice that is included in or attached to the work
+ (an example is provided in the Appendix below).
+
+ "Derivative Works" shall mean any work, whether in Source or Object
+ form, that is based on (or derived from) the Work and for which the
+ editorial revisions, annotations, elaborations, or other modifications
+ represent, as a whole, an original work of authorship. For the purposes
+ of this License, Derivative Works shall not include works that remain
+ separable from, or merely link (or bind by name) to the interfaces of,
+ the Work and Derivative Works thereof.
+
+ "Contribution" shall mean any work of authorship, including
+ the original version of the Work and any modifications or additions
+ to that Work or Derivative Works thereof, that is intentionally
+ submitted to Licensor for inclusion in the Work by the copyright owner
+ or by an individual or Legal Entity authorized to submit on behalf of
+ the copyright owner. For the purposes of this definition, "submitted"
+ means any form of electronic, verbal, or written communication sent
+ to the Licensor or its representatives, including but not limited to
+ communication on electronic mailing lists, source code control systems,
+ and issue tracking systems that are managed by, or on behalf of, the
+ Licensor for the purpose of discussing and improving the Work, but
+ excluding communication that is conspicuously marked or otherwise
+ designated in writing by the copyright owner as "Not a Contribution."
+
+ "Contributor" shall mean Licensor and any individual or Legal Entity
+ on behalf of whom a Contribution has been received by Licensor and
+ subsequently incorporated within the Work.
+
+2. Grant of Copyright License. Subject to the terms and conditions of
+ this License, each Contributor hereby grants to You a perpetual,
+ worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+ copyright license to reproduce, prepare Derivative Works of,
+ publicly display, publicly perform, sublicense, and distribute the
+ Work and such Derivative Works in Source or Object form.
+
+3. Grant of Patent License. Subject to the terms and conditions of
+ this License, each Contributor hereby grants to You a perpetual,
+ worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+ (except as stated in this section) patent license to make, have made,
+ use, offer to sell, sell, import, and otherwise transfer the Work,
+ where such license applies only to those patent claims licensable
+ by such Contributor that are necessarily infringed by their
+ Contribution(s) alone or by combination of their Contribution(s)
+ with the Work to which such Contribution(s) was submitted. If You
+ institute patent litigation against any entity (including a
+ cross-claim or counterclaim in a lawsuit) alleging that the Work
+ or a Contribution incorporated within the Work constitutes direct
+ or contributory patent infringement, then any patent licenses
+ granted to You under this License for that Work shall terminate
+ as of the date such litigation is filed.
+
+4. Redistribution. You may reproduce and distribute copies of the
+ Work or Derivative Works thereof in any medium, with or without
+ modifications, and in Source or Object form, provided that You
+ meet the following conditions:
+
+ (a) You must give any other recipients of the Work or
+ Derivative Works a copy of this License; and
+
+ (b) You must cause any modified files to carry prominent notices
+ stating that You changed the files; and
+
+ (c) You must retain, in the Source form of any Derivative Works
+ that You distribute, all copyright, patent, trademark, and
+ attribution notices from the Source form of the Work,
+ excluding those notices that do not pertain to any part of
+ the Derivative Works; and
+
+ (d) If the Work includes a "NOTICE" text file as part of its
+ distribution, then any Derivative Works that You distribute must
+ include a readable copy of the attribution notices contained
+ within such NOTICE file, excluding those notices that do not
+ pertain to any part of the Derivative Works, in at least one
+ of the following places: within a NOTICE text file distributed
+ as part of the Derivative Works; within the Source form or
+ documentation, if provided along with the Derivative Works; or,
+ within a display generated by the Derivative Works, if and
+ wherever such third-party notices normally appear. The contents
+ of the NOTICE file are for informational purposes only and
+ do not modify the License. You may add Your own attribution
+ notices within Derivative Works that You distribute, alongside
+ or as an addendum to the NOTICE text from the Work, provided
+ that such additional attribution notices cannot be construed
+ as modifying the License.
+
+ You may add Your own copyright statement to Your modifications and
+ may provide additional or different license terms and conditions
+ for use, reproduction, or distribution of Your modifications, or
+ for any such Derivative Works as a whole, provided Your use,
+ reproduction, and distribution of the Work otherwise complies with
+ the conditions stated in this License.
+
+5. Submission of Contributions. Unless You explicitly state otherwise,
+ any Contribution intentionally submitted for inclusion in the Work
+ by You to the Licensor shall be under the terms and conditions of
+ this License, without any additional terms or conditions.
+ Notwithstanding the above, nothing herein shall supersede or modify
+ the terms of any separate license agreement you may have executed
+ with Licensor regarding such Contributions.
+
+6. Trademarks. This License does not grant permission to use the trade
+ names, trademarks, service marks, or product names of the Licensor,
+ except as required for reasonable and customary use in describing the
+ origin of the Work and reproducing the content of the NOTICE file.
+
+7. Disclaimer of Warranty. Unless required by applicable law or
+ agreed to in writing, Licensor provides the Work (and each
+ Contributor provides its Contributions) on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ implied, including, without limitation, any warranties or conditions
+ of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+ PARTICULAR PURPOSE. You are solely responsible for determining the
+ appropriateness of using or redistributing the Work and assume any
+ risks associated with Your exercise of permissions under this License.
+
+8. Limitation of Liability. In no event and under no legal theory,
+ whether in tort (including negligence), contract, or otherwise,
+ unless required by applicable law (such as deliberate and grossly
+ negligent acts) or agreed to in writing, shall any Contributor be
+ liable to You for damages, including any direct, indirect, special,
+ incidental, or consequential damages of any character arising as a
+ result of this License or out of the use or inability to use the
+ Work (including but not limited to damages for loss of goodwill,
+ work stoppage, computer failure or malfunction, or any and all
+ other commercial damages or losses), even if such Contributor
+ has been advised of the possibility of such damages.
+
+9. Accepting Warranty or Additional Liability. While redistributing
+ the Work or Derivative Works thereof, You may choose to offer,
+ and charge a fee for, acceptance of support, warranty, indemnity,
+ or other liability obligations and/or rights consistent with this
+ License. However, in accepting such obligations, You may act only
+ on Your own behalf and on Your sole responsibility, not on behalf
+ of any other Contributor, and only if You agree to indemnify,
+ defend, and hold each Contributor harmless for any liability
+ incurred by, or claims asserted against, such Contributor by reason
+ of your accepting any such warranty or additional liability.
+
+END OF TERMS AND CONDITIONS
+
+APPENDIX: How to apply the Apache License to your work.
+
+ To apply the Apache License to your work, attach the following
+ boilerplate notice, with the fields enclosed by brackets "[]"
+ replaced with your own identifying information. (Don't include
+ the brackets!) The text should be enclosed in the appropriate
+ comment syntax for the file format. We also recommend that a
+ file or class name and description of purpose be included on the
+ same "printed page" as the copyright notice for easier
+ identification within third-party archives.
+
+Copyright [yyyy] [name of copyright owner]
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+ https://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
diff --git a/LICENSE-MIT b/LICENSE-MIT
new file mode 100644
index 0000000..d93b5ba
--- /dev/null
+++ b/LICENSE-MIT
@@ -0,0 +1,26 @@
+Copyright 2018 Developers of the Rand project
+Copyright (c) 2014 The Rust Project Developers
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..69a0ce7
--- /dev/null
+++ b/README.md
@@ -0,0 +1,49 @@
+# rand_chacha
+
+[](https://travis-ci.org/rust-random/rand)
+[](https://ci.appveyor.com/project/rust-random/rand)
+[](https://crates.io/crates/rand_chacha)
+[](https://rust-random.github.io/book/)
+[](https://rust-random.github.io/rand/rand_chacha)
+[](https://docs.rs/rand_chacha)
+[](https://github.com/rust-random/rand#rust-version-requirements)
+
+A cryptographically secure random number generator that uses the ChaCha
+algorithm.
+
+ChaCha is a stream cipher designed by Daniel J. Bernstein[^1], that we use
+as an RNG. It is an improved variant of the Salsa20 cipher family, which was
+selected as one of the "stream ciphers suitable for widespread adoption" by
+eSTREAM[^2].
+
+The RNGs provided by this crate are implemented via the fast stream ciphers of
+the [`c2-chacha`](https://crates.io/crates/c2-chacha) crate.
+
+Links:
+
+- [API documentation (master)](https://rust-random.github.io/rand/rand_chacha)
+- [API documentation (docs.rs)](https://docs.rs/rand_chacha)
+- [Changelog](https://github.com/rust-random/rand/blob/master/rand_chacha/CHANGELOG.md)
+
+[rand]: https://crates.io/crates/rand
+[^1]: D. J. Bernstein, [*ChaCha, a variant of Salsa20*](
+ https://cr.yp.to/chacha.html)
+
+[^2]: [eSTREAM: the ECRYPT Stream Cipher Project](
+ http://www.ecrypt.eu.org/stream/)
+
+
+## Crate Features
+
+`rand_chacha` is `no_std` compatible when disabling default features; the `std`
+feature can be explicitly required to re-enable `std` support. Using `std`
+allows detection of CPU features and thus better optimisation.
+
+
+# License
+
+`rand_chacha` is distributed under the terms of both the MIT license and the
+Apache License (Version 2.0).
+
+See [LICENSE-APACHE](LICENSE-APACHE) and [LICENSE-MIT](LICENSE-MIT), and
+[COPYRIGHT](COPYRIGHT) for details.
diff --git a/src/chacha.rs b/src/chacha.rs
new file mode 100644
index 0000000..cf68c52
--- /dev/null
+++ b/src/chacha.rs
@@ -0,0 +1,459 @@
+// Copyright 2018 Developers of the Rand project.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The ChaCha random number generator.
+
+#[cfg(not(feature = "std"))] use core;
+#[cfg(feature = "std")] use std as core;
+
+use self::core::fmt;
+use crate::guts::ChaCha;
+use rand_core::block::{BlockRng, BlockRngCore};
+use rand_core::{CryptoRng, Error, RngCore, SeedableRng};
+
+const STREAM_PARAM_NONCE: u32 = 1;
+const STREAM_PARAM_BLOCK: u32 = 0;
+
+pub struct Array64<T>([T; 64]);
+impl<T> Default for Array64<T>
+where T: Default
+{
+ #[rustfmt::skip]
+ fn default() -> Self {
+ Self([
+ T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(),
+ T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(),
+ T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(),
+ T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(),
+ T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(),
+ T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(),
+ T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(),
+ T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(), T::default(),
+ ])
+ }
+}
+impl<T> AsRef<[T]> for Array64<T> {
+ fn as_ref(&self) -> &[T] {
+ &self.0
+ }
+}
+impl<T> AsMut<[T]> for Array64<T> {
+ fn as_mut(&mut self) -> &mut [T] {
+ &mut self.0
+ }
+}
+impl<T> Clone for Array64<T>
+where T: Copy + Default
+{
+ fn clone(&self) -> Self {
+ let mut new = Self::default();
+ new.0.copy_from_slice(&self.0);
+ new
+ }
+}
+impl<T> fmt::Debug for Array64<T> {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ write!(f, "Array64 {{}}")
+ }
+}
+
+macro_rules! chacha_impl {
+ ($ChaChaXCore:ident, $ChaChaXRng:ident, $rounds:expr, $doc:expr) => {
+ #[doc=$doc]
+ #[derive(Clone)]
+ pub struct $ChaChaXCore {
+ state: ChaCha,
+ }
+
+ // Custom Debug implementation that does not expose the internal state
+ impl fmt::Debug for $ChaChaXCore {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ write!(f, "ChaChaXCore {{}}")
+ }
+ }
+
+ impl BlockRngCore for $ChaChaXCore {
+ type Item = u32;
+ type Results = Array64<u32>;
+ #[inline]
+ fn generate(&mut self, r: &mut Self::Results) {
+ // Fill slice of words by writing to equivalent slice of bytes, then fixing endianness.
+ self.state.refill4($rounds, unsafe {
+ &mut *(&mut *r as *mut Array64<u32> as *mut [u8; 256])
+ });
+ for x in r.as_mut() {
+ *x = x.to_le();
+ }
+ }
+ }
+
+ impl SeedableRng for $ChaChaXCore {
+ type Seed = [u8; 32];
+ #[inline]
+ fn from_seed(seed: Self::Seed) -> Self {
+ $ChaChaXCore { state: ChaCha::new(&seed, &[0u8; 8]) }
+ }
+ }
+
+ impl CryptoRng for $ChaChaXCore {}
+
+ /// A cryptographically secure random number generator that uses the ChaCha algorithm.
+ ///
+ /// ChaCha is a stream cipher designed by Daniel J. Bernstein[^1], that we use as an RNG. It is
+ /// an improved variant of the Salsa20 cipher family, which was selected as one of the "stream
+ /// ciphers suitable for widespread adoption" by eSTREAM[^2].
+ ///
+ /// ChaCha uses add-rotate-xor (ARX) operations as its basis. These are safe against timing
+ /// attacks, although that is mostly a concern for ciphers and not for RNGs. We provide a SIMD
+ /// implementation to support high throughput on a variety of common hardware platforms.
+ ///
+ /// With the ChaCha algorithm it is possible to choose the number of rounds the core algorithm
+ /// should run. The number of rounds is a tradeoff between performance and security, where 8
+ /// rounds is the minimum potentially secure configuration, and 20 rounds is widely used as a
+ /// conservative choice.
+ ///
+ /// We use a 64-bit counter and 64-bit stream identifier as in Bernstein's implementation[^1]
+ /// except that we use a stream identifier in place of a nonce. A 64-bit counter over 64-byte
+ /// (16 word) blocks allows 1 ZiB of output before cycling, and the stream identifier allows
+ /// 2<sup>64</sup> unique streams of output per seed. Both counter and stream are initialized
+ /// to zero but may be set via the `set_word_pos` and `set_stream` methods.
+ ///
+ /// The word layout is:
+ ///
+ /// ```text
+ /// constant constant constant constant
+ /// seed seed seed seed
+ /// seed seed seed seed
+ /// counter counter stream_id stream_id
+ /// ```
+ ///
+ /// This implementation uses an output buffer of sixteen `u32` words, and uses
+ /// [`BlockRng`] to implement the [`RngCore`] methods.
+ ///
+ /// [^1]: D. J. Bernstein, [*ChaCha, a variant of Salsa20*](
+ /// https://cr.yp.to/chacha.html)
+ ///
+ /// [^2]: [eSTREAM: the ECRYPT Stream Cipher Project](
+ /// http://www.ecrypt.eu.org/stream/)
+ #[derive(Clone, Debug)]
+ pub struct $ChaChaXRng {
+ rng: BlockRng<$ChaChaXCore>,
+ }
+
+ impl SeedableRng for $ChaChaXRng {
+ type Seed = [u8; 32];
+ #[inline]
+ fn from_seed(seed: Self::Seed) -> Self {
+ let core = $ChaChaXCore::from_seed(seed);
+ Self {
+ rng: BlockRng::new(core),
+ }
+ }
+ }
+
+ impl RngCore for $ChaChaXRng {
+ #[inline]
+ fn next_u32(&mut self) -> u32 {
+ self.rng.next_u32()
+ }
+ #[inline]
+ fn next_u64(&mut self) -> u64 {
+ self.rng.next_u64()
+ }
+ #[inline]
+ fn fill_bytes(&mut self, bytes: &mut [u8]) {
+ self.rng.fill_bytes(bytes)
+ }
+ #[inline]
+ fn try_fill_bytes(&mut self, bytes: &mut [u8]) -> Result<(), Error> {
+ self.rng.try_fill_bytes(bytes)
+ }
+ }
+
+ impl $ChaChaXRng {
+ // The buffer is a 4-block window, i.e. it is always at a block-aligned position in the
+ // stream but if the stream has been seeked it may not be self-aligned.
+
+ /// Get the offset from the start of the stream, in 32-bit words.
+ ///
+ /// Since the generated blocks are 16 words (2<sup>4</sup>) long and the
+ /// counter is 64-bits, the offset is a 68-bit number. Sub-word offsets are
+ /// not supported, hence the result can simply be multiplied by 4 to get a
+ /// byte-offset.
+ #[inline]
+ pub fn get_word_pos(&self) -> u128 {
+ let mut block = u128::from(self.rng.core.state.get_stream_param(STREAM_PARAM_BLOCK));
+ // counter is incremented *after* filling buffer
+ block -= 4;
+ (block << 4) + self.rng.index() as u128
+ }
+
+ /// Set the offset from the start of the stream, in 32-bit words.
+ ///
+ /// As with `get_word_pos`, we use a 68-bit number. Since the generator
+ /// simply cycles at the end of its period (1 ZiB), we ignore the upper
+ /// 60 bits.
+ #[inline]
+ pub fn set_word_pos(&mut self, word_offset: u128) {
+ let block = (word_offset >> 4) as u64;
+ self.rng
+ .core
+ .state
+ .set_stream_param(STREAM_PARAM_BLOCK, block);
+ self.rng.generate_and_set((word_offset & 15) as usize);
+ }
+
+ /// Set the stream number.
+ ///
+ /// This is initialized to zero; 2<sup>64</sup> unique streams of output
+ /// are available per seed/key.
+ ///
+ /// Note that in order to reproduce ChaCha output with a specific 64-bit
+ /// nonce, one can convert that nonce to a `u64` in little-endian fashion
+ /// and pass to this function. In theory a 96-bit nonce can be used by
+ /// passing the last 64-bits to this function and using the first 32-bits as
+ /// the most significant half of the 64-bit counter (which may be set
+ /// indirectly via `set_word_pos`), but this is not directly supported.
+ #[inline]
+ pub fn set_stream(&mut self, stream: u64) {
+ self.rng
+ .core
+ .state
+ .set_stream_param(STREAM_PARAM_NONCE, stream);
+ if self.rng.index() != 64 {
+ let wp = self.get_word_pos();
+ self.set_word_pos(wp);
+ }
+ }
+ }
+
+ impl CryptoRng for $ChaChaXRng {}
+
+ impl From<$ChaChaXCore> for $ChaChaXRng {
+ fn from(core: $ChaChaXCore) -> Self {
+ $ChaChaXRng {
+ rng: BlockRng::new(core),
+ }
+ }
+ }
+ }
+}
+
+chacha_impl!(ChaCha20Core, ChaCha20Rng, 10, "ChaCha with 20 rounds");
+chacha_impl!(ChaCha12Core, ChaCha12Rng, 6, "ChaCha with 12 rounds");
+chacha_impl!(ChaCha8Core, ChaCha8Rng, 4, "ChaCha with 8 rounds");
+
+#[cfg(test)]
+mod test {
+ use rand_core::{RngCore, SeedableRng};
+
+ type ChaChaRng = super::ChaCha20Rng;
+
+ #[test]
+ fn test_chacha_construction() {
+ let seed = [
+ 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0,
+ 0, 0, 0,
+ ];
+ let mut rng1 = ChaChaRng::from_seed(seed);
+ assert_eq!(rng1.next_u32(), 137206642);
+
+ let mut rng2 = ChaChaRng::from_rng(rng1).unwrap();
+ assert_eq!(rng2.next_u32(), 1325750369);
+ }
+
+ #[test]
+ fn test_chacha_true_values_a() {
+ // Test vectors 1 and 2 from
+ // https://tools.ietf.org/html/draft-nir-cfrg-chacha20-poly1305-04
+ let seed = [0u8; 32];
+ let mut rng = ChaChaRng::from_seed(seed);
+
+ let mut results = [0u32; 16];
+ for i in results.iter_mut() {
+ *i = rng.next_u32();
+ }
+ let expected = [
+ 0xade0b876, 0x903df1a0, 0xe56a5d40, 0x28bd8653, 0xb819d2bd, 0x1aed8da0, 0xccef36a8,
+ 0xc70d778b, 0x7c5941da, 0x8d485751, 0x3fe02477, 0x374ad8b8, 0xf4b8436a, 0x1ca11815,
+ 0x69b687c3, 0x8665eeb2,
+ ];
+ assert_eq!(results, expected);
+
+ for i in results.iter_mut() {
+ *i = rng.next_u32();
+ }
+ let expected = [
+ 0xbee7079f, 0x7a385155, 0x7c97ba98, 0x0d082d73, 0xa0290fcb, 0x6965e348, 0x3e53c612,
+ 0xed7aee32, 0x7621b729, 0x434ee69c, 0xb03371d5, 0xd539d874, 0x281fed31, 0x45fb0a51,
+ 0x1f0ae1ac, 0x6f4d794b,
+ ];
+ assert_eq!(results, expected);
+ }
+
+ #[test]
+ fn test_chacha_true_values_b() {
+ // Test vector 3 from
+ // https://tools.ietf.org/html/draft-nir-cfrg-chacha20-poly1305-04
+ let seed = [
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 1,
+ ];
+ let mut rng = ChaChaRng::from_seed(seed);
+
+ // Skip block 0
+ for _ in 0..16 {
+ rng.next_u32();
+ }
+
+ let mut results = [0u32; 16];
+ for i in results.iter_mut() {
+ *i = rng.next_u32();
+ }
+ let expected = [
+ 0x2452eb3a, 0x9249f8ec, 0x8d829d9b, 0xddd4ceb1, 0xe8252083, 0x60818b01, 0xf38422b8,
+ 0x5aaa49c9, 0xbb00ca8e, 0xda3ba7b4, 0xc4b592d1, 0xfdf2732f, 0x4436274e, 0x2561b3c8,
+ 0xebdd4aa6, 0xa0136c00,
+ ];
+ assert_eq!(results, expected);
+ }
+
+ #[test]
+ fn test_chacha_true_values_c() {
+ // Test vector 4 from
+ // https://tools.ietf.org/html/draft-nir-cfrg-chacha20-poly1305-04
+ let seed = [
+ 0, 0xff, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0,
+ ];
+ let expected = [
+ 0xfb4dd572, 0x4bc42ef1, 0xdf922636, 0x327f1394, 0xa78dea8f, 0x5e269039, 0xa1bebbc1,
+ 0xcaf09aae, 0xa25ab213, 0x48a6b46c, 0x1b9d9bcb, 0x092c5be6, 0x546ca624, 0x1bec45d5,
+ 0x87f47473, 0x96f0992e,
+ ];
+ let expected_end = 3 * 16;
+ let mut results = [0u32; 16];
+
+ // Test block 2 by skipping block 0 and 1
+ let mut rng1 = ChaChaRng::from_seed(seed);
+ for _ in 0..32 {
+ rng1.next_u32();
+ }
+ for i in results.iter_mut() {
+ *i = rng1.next_u32();
+ }
+ assert_eq!(results, expected);
+ assert_eq!(rng1.get_word_pos(), expected_end);
+
+ // Test block 2 by using `set_word_pos`
+ let mut rng2 = ChaChaRng::from_seed(seed);
+ rng2.set_word_pos(2 * 16);
+ for i in results.iter_mut() {
+ *i = rng2.next_u32();
+ }
+ assert_eq!(results, expected);
+ assert_eq!(rng2.get_word_pos(), expected_end);
+
+ // Test skipping behaviour with other types
+ let mut buf = [0u8; 32];
+ rng2.fill_bytes(&mut buf[..]);
+ assert_eq!(rng2.get_word_pos(), expected_end + 8);
+ rng2.fill_bytes(&mut buf[0..25]);
+ assert_eq!(rng2.get_word_pos(), expected_end + 15);
+ rng2.next_u64();
+ assert_eq!(rng2.get_word_pos(), expected_end + 17);
+ rng2.next_u32();
+ rng2.next_u64();
+ assert_eq!(rng2.get_word_pos(), expected_end + 20);
+ rng2.fill_bytes(&mut buf[0..1]);
+ assert_eq!(rng2.get_word_pos(), expected_end + 21);
+ }
+
+ #[test]
+ fn test_chacha_multiple_blocks() {
+ let seed = [
+ 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0, 4, 0, 0, 0, 5, 0, 0, 0, 6, 0, 0, 0, 7,
+ 0, 0, 0,
+ ];
+ let mut rng = ChaChaRng::from_seed(seed);
+
+ // Store the 17*i-th 32-bit word,
+ // i.e., the i-th word of the i-th 16-word block
+ let mut results = [0u32; 16];
+ for i in results.iter_mut() {
+ *i = rng.next_u32();
+ for _ in 0..16 {
+ rng.next_u32();
+ }
+ }
+ let expected = [
+ 0xf225c81a, 0x6ab1be57, 0x04d42951, 0x70858036, 0x49884684, 0x64efec72, 0x4be2d186,
+ 0x3615b384, 0x11cfa18e, 0xd3c50049, 0x75c775f6, 0x434c6530, 0x2c5bad8f, 0x898881dc,
+ 0x5f1c86d9, 0xc1f8e7f4,
+ ];
+ assert_eq!(results, expected);
+ }
+
+ #[test]
+ fn test_chacha_true_bytes() {
+ let seed = [0u8; 32];
+ let mut rng = ChaChaRng::from_seed(seed);
+ let mut results = [0u8; 32];
+ rng.fill_bytes(&mut results);
+ let expected = [
+ 118, 184, 224, 173, 160, 241, 61, 144, 64, 93, 106, 229, 83, 134, 189, 40, 189, 210,
+ 25, 184, 160, 141, 237, 26, 168, 54, 239, 204, 139, 119, 13, 199,
+ ];
+ assert_eq!(results, expected);
+ }
+
+ #[test]
+ fn test_chacha_nonce() {
+ // Test vector 5 from
+ // https://tools.ietf.org/html/draft-nir-cfrg-chacha20-poly1305-04
+ // Although we do not support setting a nonce, we try it here anyway so
+ // we can use this test vector.
+ let seed = [0u8; 32];
+ let mut rng = ChaChaRng::from_seed(seed);
+ // 96-bit nonce in LE order is: 0,0,0,0, 0,0,0,0, 0,0,0,2
+ rng.set_stream(2u64 << (24 + 32));
+
+ let mut results = [0u32; 16];
+ for i in results.iter_mut() {
+ *i = rng.next_u32();
+ }
+ let expected = [
+ 0x374dc6c2, 0x3736d58c, 0xb904e24a, 0xcd3f93ef, 0x88228b1a, 0x96a4dfb3, 0x5b76ab72,
+ 0xc727ee54, 0x0e0e978a, 0xf3145c95, 0x1b748ea8, 0xf786c297, 0x99c28f5f, 0x628314e8,
+ 0x398a19fa, 0x6ded1b53,
+ ];
+ assert_eq!(results, expected);
+ }
+
+ #[test]
+ fn test_chacha_clone_streams() {
+ let seed = [
+ 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0, 4, 0, 0, 0, 5, 0, 0, 0, 6, 0, 0, 0, 7,
+ 0, 0, 0,
+ ];
+ let mut rng = ChaChaRng::from_seed(seed);
+ let mut clone = rng.clone();
+ for _ in 0..16 {
+ assert_eq!(rng.next_u64(), clone.next_u64());
+ }
+
+ rng.set_stream(51);
+ for _ in 0..7 {
+ assert!(rng.next_u32() != clone.next_u32());
+ }
+ clone.set_stream(51); // switch part way through block
+ for _ in 7..16 {
+ assert_eq!(rng.next_u32(), clone.next_u32());
+ }
+ }
+}
diff --git a/src/guts.rs b/src/guts.rs
new file mode 100644
index 0000000..7561c1b
--- /dev/null
+++ b/src/guts.rs
@@ -0,0 +1,243 @@
+// Copyright 2019 The CryptoCorrosion Contributors
+// Copyright 2020 Developers of the Rand project.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The ChaCha random number generator.
+
+use ppv_lite86::{dispatch, dispatch_light128};
+
+pub use ppv_lite86::Machine;
+use ppv_lite86::{vec128_storage, ArithOps, BitOps32, LaneWords4, MultiLane, StoreBytes, Vec4};
+
+pub(crate) const BLOCK: usize = 64;
+pub(crate) const BLOCK64: u64 = BLOCK as u64;
+const LOG2_BUFBLOCKS: u64 = 2;
+const BUFBLOCKS: u64 = 1 << LOG2_BUFBLOCKS;
+pub(crate) const BUFSZ64: u64 = BLOCK64 * BUFBLOCKS;
+pub(crate) const BUFSZ: usize = BUFSZ64 as usize;
+
+#[derive(Clone)]
+pub struct ChaCha {
+ pub(crate) b: vec128_storage,
+ pub(crate) c: vec128_storage,
+ pub(crate) d: vec128_storage,
+}
+
+#[derive(Clone)]
+pub struct State<V> {
+ pub(crate) a: V,
+ pub(crate) b: V,
+ pub(crate) c: V,
+ pub(crate) d: V,
+}
+
+#[inline(always)]
+pub(crate) fn round<V: ArithOps + BitOps32>(mut x: State<V>) -> State<V> {
+ x.a += x.b;
+ x.d = (x.d ^ x.a).rotate_each_word_right16();
+ x.c += x.d;
+ x.b = (x.b ^ x.c).rotate_each_word_right20();
+ x.a += x.b;
+ x.d = (x.d ^ x.a).rotate_each_word_right24();
+ x.c += x.d;
+ x.b = (x.b ^ x.c).rotate_each_word_right25();
+ x
+}
+
+#[inline(always)]
+pub(crate) fn diagonalize<V: LaneWords4>(mut x: State<V>) -> State<V> {
+ x.b = x.b.shuffle_lane_words3012();
+ x.c = x.c.shuffle_lane_words2301();
+ x.d = x.d.shuffle_lane_words1230();
+ x
+}
+#[inline(always)]
+pub(crate) fn undiagonalize<V: LaneWords4>(mut x: State<V>) -> State<V> {
+ x.b = x.b.shuffle_lane_words1230();
+ x.c = x.c.shuffle_lane_words2301();
+ x.d = x.d.shuffle_lane_words3012();
+ x
+}
+
+impl ChaCha {
+ #[inline(always)]
+ pub fn new(key: &[u8; 32], nonce: &[u8]) -> Self {
+ init_chacha(key, nonce)
+ }
+
+ #[inline(always)]
+ fn pos64<M: Machine>(&self, m: M) -> u64 {
+ let d: M::u32x4 = m.unpack(self.d);
+ ((d.extract(1) as u64) << 32) | d.extract(0) as u64
+ }
+
+ /// Produce 4 blocks of output, advancing the state
+ #[inline(always)]
+ pub fn refill4(&mut self, drounds: u32, out: &mut [u8; BUFSZ]) {
+ refill_wide(self, drounds, out)
+ }
+
+ #[inline(always)]
+ pub fn set_stream_param(&mut self, param: u32, value: u64) {
+ set_stream_param(self, param, value)
+ }
+
+ #[inline(always)]
+ pub fn get_stream_param(&self, param: u32) -> u64 {
+ get_stream_param(self, param)
+ }
+}
+
+#[inline(always)]
+fn refill_wide_impl<Mach: Machine>(
+ m: Mach, state: &mut ChaCha, drounds: u32, out: &mut [u8; BUFSZ],
+) {
+ let k = m.vec([0x6170_7865, 0x3320_646e, 0x7962_2d32, 0x6b20_6574]);
+ let mut pos = state.pos64(m);
+ let d0: Mach::u32x4 = m.unpack(state.d);
+ pos += 1;
+ let d1 = d0.insert((pos >> 32) as u32, 1).insert(pos as u32, 0);
+ pos += 1;
+ let d2 = d0.insert((pos >> 32) as u32, 1).insert(pos as u32, 0);
+ pos += 1;
+ let d3 = d0.insert((pos >> 32) as u32, 1).insert(pos as u32, 0);
+
+ let b = m.unpack(state.b);
+ let c = m.unpack(state.c);
+ let mut x = State {
+ a: Mach::u32x4x4::from_lanes([k, k, k, k]),
+ b: Mach::u32x4x4::from_lanes([b, b, b, b]),
+ c: Mach::u32x4x4::from_lanes([c, c, c, c]),
+ d: m.unpack(Mach::u32x4x4::from_lanes([d0, d1, d2, d3]).into()),
+ };
+ for _ in 0..drounds {
+ x = round(x);
+ x = undiagonalize(round(diagonalize(x)));
+ }
+ let mut pos = state.pos64(m);
+ let d0: Mach::u32x4 = m.unpack(state.d);
+ pos += 1;
+ let d1 = d0.insert((pos >> 32) as u32, 1).insert(pos as u32, 0);
+ pos += 1;
+ let d2 = d0.insert((pos >> 32) as u32, 1).insert(pos as u32, 0);
+ pos += 1;
+ let d3 = d0.insert((pos >> 32) as u32, 1).insert(pos as u32, 0);
+ pos += 1;
+ let d4 = d0.insert((pos >> 32) as u32, 1).insert(pos as u32, 0);
+
+ let (a, b, c, d) = (
+ x.a.to_lanes(),
+ x.b.to_lanes(),
+ x.c.to_lanes(),
+ x.d.to_lanes(),
+ );
+ let sb = m.unpack(state.b);
+ let sc = m.unpack(state.c);
+ let sd = [m.unpack(state.d), d1, d2, d3];
+ state.d = d4.into();
+ let mut words = out.chunks_exact_mut(16);
+ for ((((&a, &b), &c), &d), &sd) in a.iter().zip(&b).zip(&c).zip(&d).zip(&sd) {
+ (a + k).write_le(words.next().unwrap());
+ (b + sb).write_le(words.next().unwrap());
+ (c + sc).write_le(words.next().unwrap());
+ (d + sd).write_le(words.next().unwrap());
+ }
+}
+
+dispatch!(m, Mach, {
+ fn refill_wide(state: &mut ChaCha, drounds: u32, out: &mut [u8; BUFSZ]) {
+ refill_wide_impl(m, state, drounds, out);
+ }
+});
+
+// Single-block, rounds-only; shared by try_apply_keystream for tails shorter than BUFSZ
+// and XChaCha's setup step.
+dispatch!(m, Mach, {
+ fn refill_narrow_rounds(state: &mut ChaCha, drounds: u32) -> State<vec128_storage> {
+ let k: Mach::u32x4 = m.vec([0x6170_7865, 0x3320_646e, 0x7962_2d32, 0x6b20_6574]);
+ let mut x = State {
+ a: k,
+ b: m.unpack(state.b),
+ c: m.unpack(state.c),
+ d: m.unpack(state.d),
+ };
+ for _ in 0..drounds {
+ x = round(x);
+ x = undiagonalize(round(diagonalize(x)));
+ }
+ State {
+ a: x.a.into(),
+ b: x.b.into(),
+ c: x.c.into(),
+ d: x.d.into(),
+ }
+ }
+});
+
+dispatch_light128!(m, Mach, {
+ fn set_stream_param(state: &mut ChaCha, param: u32, value: u64) {
+ let d: Mach::u32x4 = m.unpack(state.d);
+ state.d = d
+ .insert((value >> 32) as u32, (param << 1) | 1)
+ .insert(value as u32, param << 1)
+ .into();
+ }
+});
+
+dispatch_light128!(m, Mach, {
+ fn get_stream_param(state: &ChaCha, param: u32) -> u64 {
+ let d: Mach::u32x4 = m.unpack(state.d);
+ ((d.extract((param << 1) | 1) as u64) << 32) | d.extract(param << 1) as u64
+ }
+});
+
+fn read_u32le(xs: &[u8]) -> u32 {
+ assert_eq!(xs.len(), 4);
+ u32::from(xs[0]) | (u32::from(xs[1]) << 8) | (u32::from(xs[2]) << 16) | (u32::from(xs[3]) << 24)
+}
+
+dispatch_light128!(m, Mach, {
+ fn init_chacha(key: &[u8; 32], nonce: &[u8]) -> ChaCha {
+ let ctr_nonce = [
+ 0,
+ if nonce.len() == 12 {
+ read_u32le(&nonce[0..4])
+ } else {
+ 0
+ },
+ read_u32le(&nonce[nonce.len() - 8..nonce.len() - 4]),
+ read_u32le(&nonce[nonce.len() - 4..]),
+ ];
+ let key0: Mach::u32x4 = m.read_le(&key[..16]);
+ let key1: Mach::u32x4 = m.read_le(&key[16..]);
+ ChaCha {
+ b: key0.into(),
+ c: key1.into(),
+ d: ctr_nonce.into(),
+ }
+ }
+});
+
+dispatch_light128!(m, Mach, {
+ fn init_chacha_x(key: &[u8; 32], nonce: &[u8; 24], rounds: u32) -> ChaCha {
+ let key0: Mach::u32x4 = m.read_le(&key[..16]);
+ let key1: Mach::u32x4 = m.read_le(&key[16..]);
+ let nonce0: Mach::u32x4 = m.read_le(&nonce[..16]);
+ let mut state = ChaCha {
+ b: key0.into(),
+ c: key1.into(),
+ d: nonce0.into(),
+ };
+ let x = refill_narrow_rounds(&mut state, rounds);
+ let ctr_nonce1 = [0, 0, read_u32le(&nonce[16..20]), read_u32le(&nonce[20..24])];
+ state.b = x.a;
+ state.c = x.d;
+ state.d = ctr_nonce1.into();
+ state
+ }
+});
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..24125b4
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,33 @@
+// Copyright 2018 Developers of the Rand project.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! The ChaCha random number generator.
+
+#![doc(
+ html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk.png",
+ html_favicon_url = "https://www.rust-lang.org/favicon.ico",
+ html_root_url = "https://rust-random.github.io/rand/"
+)]
+#![deny(missing_docs)]
+#![deny(missing_debug_implementations)]
+#![doc(test(attr(allow(unused_variables), deny(warnings))))]
+#![cfg_attr(not(feature = "std"), no_std)]
+
+pub use rand_core;
+
+mod chacha;
+mod guts;
+
+pub use crate::chacha::{
+ ChaCha12Core, ChaCha12Rng, ChaCha20Core, ChaCha20Rng, ChaCha8Core, ChaCha8Rng,
+};
+
+/// ChaCha with 20 rounds
+pub type ChaChaRng = ChaCha20Rng;
+/// ChaCha with 20 rounds, low-level interface
+pub type ChaChaCore = ChaCha20Core;
