From: Matt Corallo <git@bluematt.me>
Date: Thu, 13 Dec 2018 22:18:31 +0000 (-0500)
Subject: Steal rust-crypto's ChaCha20 implementation wholesale
X-Git-Tag: v0.0.12~253^2~4
X-Git-Url: http://git.bitcoin.ninja/?a=commitdiff_plain;h=09c7f2f641d2496c2a6280b032f62b6249298a0f;p=rust-lightning

Steal rust-crypto's ChaCha20 implementation wholesale
---

diff --git a/src/ln/channelmanager.rs b/src/ln/channelmanager.rs
index 28bf4fd7f..ae931538d 100644
--- a/src/ln/channelmanager.rs
+++ b/src/ln/channelmanager.rs
@@ -34,7 +34,7 @@ use chain::keysinterface::KeysInterface;
 use util::config::UserConfig;
 use util::{byte_utils, events, internal_traits, rng};
 use util::ser::{Readable, ReadableArgs, Writeable, Writer};
-use util::chacha20poly1305rfc::ChaCha20;
+use util::chacha20::ChaCha20;
 use util::logger::Logger;
 use util::errors::APIError;
 use util::errors;
diff --git a/src/util/byte_utils.rs b/src/util/byte_utils.rs
index b9ca3f6b6..7230a4e1c 100644
--- a/src/util/byte_utils.rs
+++ b/src/util/byte_utils.rs
@@ -11,6 +11,13 @@ pub fn slice_to_be32(v: &[u8]) -> u32 {
 	((v[3] as u32) << 8*0)
 }
 #[inline]
+pub fn slice_to_le32(v: &[u8]) -> u32 {
+	((v[0] as u32) << 8*0) |
+	((v[1] as u32) << 8*1) |
+	((v[2] as u32) << 8*2) |
+	((v[3] as u32) << 8*3)
+}
+#[inline]
 pub fn slice_to_be48(v: &[u8]) -> u64 {
 	((v[0] as u64) << 8*5) |
 	((v[1] as u64) << 8*4) |
@@ -48,6 +55,15 @@ pub fn be32_to_array(u: u32) -> [u8; 4] {
 	v
 }
 #[inline]
+pub fn le32_to_array(u: u32) -> [u8; 4] {
+	let mut v = [0; 4];
+	v[0] = ((u >> 8*0) & 0xff) as u8;
+	v[1] = ((u >> 8*1) & 0xff) as u8;
+	v[2] = ((u >> 8*2) & 0xff) as u8;
+	v[3] = ((u >> 8*3) & 0xff) as u8;
+	v
+}
+#[inline]
 pub fn be48_to_array(u: u64) -> [u8; 6] {
 	assert!(u & 0xffff_0000_0000_0000 == 0);
 	let mut v = [0; 6];
diff --git a/src/util/chacha20.rs b/src/util/chacha20.rs
new file mode 100644
index 000000000..7bab9c1e3
--- /dev/null
+++ b/src/util/chacha20.rs
@@ -0,0 +1,558 @@
+// This file was stolen from rust-crypto.
+// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+
+// 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. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[cfg(not(feature = "fuzztarget"))]
+mod real_chacha {
+	use std::cmp;
+	use util::byte_utils::{slice_to_le32, le32_to_array};
+	use crypto::symmetriccipher::SynchronousStreamCipher;
+
+	#[derive(Clone, Copy, PartialEq, Eq)]
+	#[allow(non_camel_case_types)]
+	struct u32x4(pub u32, pub u32, pub u32, pub u32);
+	impl ::std::ops::Add for u32x4 {
+		type Output = u32x4;
+		fn add(self, rhs: u32x4) -> u32x4 {
+			u32x4(self.0.wrapping_add(rhs.0),
+			      self.1.wrapping_add(rhs.1),
+			      self.2.wrapping_add(rhs.2),
+			      self.3.wrapping_add(rhs.3))
+		}
+	}
+	impl ::std::ops::Sub for u32x4 {
+		type Output = u32x4;
+		fn sub(self, rhs: u32x4) -> u32x4 {
+			u32x4(self.0.wrapping_sub(rhs.0),
+			      self.1.wrapping_sub(rhs.1),
+			      self.2.wrapping_sub(rhs.2),
+			      self.3.wrapping_sub(rhs.3))
+		}
+	}
+	impl ::std::ops::BitXor for u32x4 {
+		type Output = u32x4;
+		fn bitxor(self, rhs: u32x4) -> u32x4 {
+			u32x4(self.0 ^ rhs.0, self.1 ^ rhs.1, self.2 ^ rhs.2, self.3 ^ rhs.3)
+		}
+	}
+	impl ::std::ops::Shr<u32x4> for u32x4 {
+		type Output = u32x4;
+		fn shr(self, rhs: u32x4) -> u32x4 {
+			u32x4(self.0 >> rhs.0, self.1 >> rhs.1, self.2 >> rhs.2, self.3 >> rhs.3)
+		}
+	}
+	impl ::std::ops::Shl<u32x4> for u32x4 {
+		type Output = u32x4;
+		fn shl(self, rhs: u32x4) -> u32x4 {
+			u32x4(self.0 << rhs.0, self.1 << rhs.1, self.2 << rhs.2, self.3 << rhs.3)
+		}
+	}
+
+	#[derive(Clone,Copy)]
+	struct ChaChaState {
+		a: u32x4,
+		b: u32x4,
+		c: u32x4,
+		d: u32x4
+	}
+
+	#[derive(Copy)]
+	pub struct ChaCha20 {
+		state  : ChaChaState,
+		output : [u8; 64],
+		offset : usize,
+	}
+
+	impl Clone for ChaCha20 { fn clone(&self) -> ChaCha20 { *self } }
+
+	macro_rules! swizzle {
+		($b: expr, $c: expr, $d: expr) => {{
+			let u32x4(b10, b11, b12, b13) = $b;
+			$b = u32x4(b11, b12, b13, b10);
+			let u32x4(c10, c11, c12, c13) = $c;
+			$c = u32x4(c12, c13,c10, c11);
+			let u32x4(d10, d11, d12, d13) = $d;
+			$d = u32x4(d13, d10, d11, d12);
+		}}
+	}
+
+	macro_rules! state_to_buffer {
+		($state: expr, $output: expr) => {{
+			let u32x4(a1, a2, a3, a4) = $state.a;
+			let u32x4(b1, b2, b3, b4) = $state.b;
+			let u32x4(c1, c2, c3, c4) = $state.c;
+			let u32x4(d1, d2, d3, d4) = $state.d;
+			let lens = [
+				a1,a2,a3,a4,
+				b1,b2,b3,b4,
+				c1,c2,c3,c4,
+				d1,d2,d3,d4
+			];
+			for i in 0..lens.len() {
+				$output[i*4..(i+1)*4].copy_from_slice(&le32_to_array(lens[i]));
+			}
+		}}
+	}
+
+	macro_rules! round{
+		($state: expr) => {{
+			$state.a = $state.a + $state.b;
+			rotate!($state.d, $state.a, S16);
+			$state.c = $state.c + $state.d;
+			rotate!($state.b, $state.c, S12);
+			$state.a = $state.a + $state.b;
+			rotate!($state.d, $state.a, S8);
+			$state.c = $state.c + $state.d;
+			rotate!($state.b, $state.c, S7);
+		}}
+	}
+
+	macro_rules! rotate {
+		($a: expr, $b: expr, $c:expr) => {{
+			let v = $a ^ $b;
+			let r = S32 - $c;
+			let right = v >> r;
+			$a = (v << $c) ^ right
+		}}
+	}
+
+	const S32:u32x4 = u32x4(32, 32, 32, 32);
+	const S16:u32x4 = u32x4(16, 16, 16, 16);
+	const S12:u32x4 = u32x4(12, 12, 12, 12);
+	const S8:u32x4 = u32x4(8, 8, 8, 8);
+	const S7:u32x4 = u32x4(7, 7, 7, 7);
+
+	impl ChaCha20 {
+		pub fn new(key: &[u8], nonce: &[u8]) -> ChaCha20 {
+			assert!(key.len() == 16 || key.len() == 32);
+			assert!(nonce.len() == 8 || nonce.len() == 12);
+
+			ChaCha20{ state: ChaCha20::expand(key, nonce), output: [0u8; 64], offset: 64 }
+		}
+
+		fn expand(key: &[u8], nonce: &[u8]) -> ChaChaState {
+			let constant = match key.len() {
+				16 => b"expand 16-byte k",
+				32 => b"expand 32-byte k",
+				_  => unreachable!(),
+			};
+			ChaChaState {
+				a: u32x4(
+					slice_to_le32(&constant[0..4]),
+					slice_to_le32(&constant[4..8]),
+					slice_to_le32(&constant[8..12]),
+					slice_to_le32(&constant[12..16])
+				),
+				b: u32x4(
+					slice_to_le32(&key[0..4]),
+					slice_to_le32(&key[4..8]),
+					slice_to_le32(&key[8..12]),
+					slice_to_le32(&key[12..16])
+				),
+				c: if key.len() == 16 {
+					u32x4(
+						slice_to_le32(&key[0..4]),
+						slice_to_le32(&key[4..8]),
+						slice_to_le32(&key[8..12]),
+						slice_to_le32(&key[12..16])
+					)
+				} else {
+					u32x4(
+						slice_to_le32(&key[16..20]),
+						slice_to_le32(&key[20..24]),
+						slice_to_le32(&key[24..28]),
+						slice_to_le32(&key[28..32])
+					)
+				},
+				d: if nonce.len() == 16 {
+					u32x4(
+						slice_to_le32(&nonce[0..4]),
+						slice_to_le32(&nonce[4..8]),
+						slice_to_le32(&nonce[8..12]),
+						slice_to_le32(&nonce[12..16])
+					)
+				} else if nonce.len() == 12 {
+					u32x4(
+						0,
+						slice_to_le32(&nonce[0..4]),
+						slice_to_le32(&nonce[4..8]),
+						slice_to_le32(&nonce[8..12])
+					)
+				} else {
+					u32x4(
+						0,
+						0,
+						slice_to_le32(&nonce[0..4]),
+						slice_to_le32(&nonce[4..8])
+					)
+				}
+			}
+		}
+
+		// put the the next 64 keystream bytes into self.output
+		fn update(&mut self) {
+			let mut state = self.state;
+
+			for _ in 0..10 {
+				round!(state);
+				swizzle!(state.b, state.c, state.d);
+				round!(state);
+				swizzle!(state.d, state.c, state.b);
+			}
+			state.a = state.a + self.state.a;
+			state.b = state.b + self.state.b;
+			state.c = state.c + self.state.c;
+			state.d = state.d + self.state.d;
+
+			state_to_buffer!(state, self.output);
+
+			self.state.d = self.state.d + u32x4(1, 0, 0, 0);
+			let u32x4(c12, _, _, _) = self.state.d;
+			if c12 == 0 {
+				// we could increment the other counter word with an 8 byte nonce
+				// but other implementations like boringssl have this same
+				// limitation
+				panic!("counter is exhausted");
+			}
+
+			self.offset = 0;
+		}
+	}
+
+	impl SynchronousStreamCipher for ChaCha20 {
+		fn process(&mut self, input: &[u8], output: &mut [u8]) {
+			assert!(input.len() == output.len());
+			let len = input.len();
+			let mut i = 0;
+			while i < len {
+				// If there is no keystream available in the output buffer,
+				// generate the next block.
+				if self.offset == 64 {
+					self.update();
+				}
+
+				// Process the min(available keystream, remaining input length).
+				let count = cmp::min(64 - self.offset, len - i);
+				// explicitly assert lengths to avoid bounds checks:
+				assert!(output.len() >= i + count);
+				assert!(input.len() >= i + count);
+				assert!(self.output.len() >= self.offset + count);
+				for j in 0..count {
+					output[i + j] = input[i + j] ^ self.output[self.offset + j];
+				}
+				i += count;
+				self.offset += count;
+			}
+		}
+	}
+}
+#[cfg(not(feature = "fuzztarget"))]
+pub use self::real_chacha::ChaCha20;
+
+#[cfg(feature = "fuzztarget")]
+mod fuzzy_chacha {
+	use crypto::symmetriccipher::SynchronousStreamCipher;
+
+	pub struct ChaCha20 {}
+
+	impl ChaCha20 {
+		pub fn new(key: &[u8], nonce: &[u8]) -> ChaCha20 {
+			assert!(key.len() == 16 || key.len() == 32);
+			assert!(nonce.len() == 8 || nonce.len() == 12);
+			Self {}
+		}
+	}
+
+	impl SynchronousStreamCipher for ChaCha20 {
+		fn process(&mut self, input: &[u8], output: &mut [u8]) {
+			output.copy_from_slice(input);
+		}
+	}
+}
+#[cfg(feature = "fuzztarget")]
+pub use self::fuzzy_chacha::ChaCha20;
+
+#[cfg(test)]
+mod test {
+	use std::iter::repeat;
+
+	use super::ChaCha20;
+	use crypto::symmetriccipher::SynchronousStreamCipher;
+
+	#[test]
+	fn test_chacha20_256_tls_vectors() {
+		struct TestVector {
+			key:   [u8; 32],
+			nonce: [u8; 8],
+			keystream: Vec<u8>,
+		};
+		// taken from http://tools.ietf.org/html/draft-agl-tls-chacha20poly1305-04
+		let test_vectors = vec!(
+			TestVector{
+				key: [
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+				],
+				nonce: [ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 ],
+				keystream: vec!(
+					0x76, 0xb8, 0xe0, 0xad, 0xa0, 0xf1, 0x3d, 0x90,
+					0x40, 0x5d, 0x6a, 0xe5, 0x53, 0x86, 0xbd, 0x28,
+					0xbd, 0xd2, 0x19, 0xb8, 0xa0, 0x8d, 0xed, 0x1a,
+					0xa8, 0x36, 0xef, 0xcc, 0x8b, 0x77, 0x0d, 0xc7,
+					0xda, 0x41, 0x59, 0x7c, 0x51, 0x57, 0x48, 0x8d,
+					0x77, 0x24, 0xe0, 0x3f, 0xb8, 0xd8, 0x4a, 0x37,
+					0x6a, 0x43, 0xb8, 0xf4, 0x15, 0x18, 0xa1, 0x1c,
+					0xc3, 0x87, 0xb6, 0x69, 0xb2, 0xee, 0x65, 0x86,
+				),
+			}, TestVector{
+				key: [
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
+				],
+				nonce: [ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 ],
+				keystream: vec!(
+					0x45, 0x40, 0xf0, 0x5a, 0x9f, 0x1f, 0xb2, 0x96,
+					0xd7, 0x73, 0x6e, 0x7b, 0x20, 0x8e, 0x3c, 0x96,
+					0xeb, 0x4f, 0xe1, 0x83, 0x46, 0x88, 0xd2, 0x60,
+					0x4f, 0x45, 0x09, 0x52, 0xed, 0x43, 0x2d, 0x41,
+					0xbb, 0xe2, 0xa0, 0xb6, 0xea, 0x75, 0x66, 0xd2,
+					0xa5, 0xd1, 0xe7, 0xe2, 0x0d, 0x42, 0xaf, 0x2c,
+					0x53, 0xd7, 0x92, 0xb1, 0xc4, 0x3f, 0xea, 0x81,
+					0x7e, 0x9a, 0xd2, 0x75, 0xae, 0x54, 0x69, 0x63,
+				),
+			}, TestVector{
+				key: [
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+				],
+				nonce: [ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 ],
+				keystream: vec!(
+					0xde, 0x9c, 0xba, 0x7b, 0xf3, 0xd6, 0x9e, 0xf5,
+					0xe7, 0x86, 0xdc, 0x63, 0x97, 0x3f, 0x65, 0x3a,
+					0x0b, 0x49, 0xe0, 0x15, 0xad, 0xbf, 0xf7, 0x13,
+					0x4f, 0xcb, 0x7d, 0xf1, 0x37, 0x82, 0x10, 0x31,
+					0xe8, 0x5a, 0x05, 0x02, 0x78, 0xa7, 0x08, 0x45,
+					0x27, 0x21, 0x4f, 0x73, 0xef, 0xc7, 0xfa, 0x5b,
+					0x52, 0x77, 0x06, 0x2e, 0xb7, 0xa0, 0x43, 0x3e,
+					0x44, 0x5f, 0x41, 0xe3,
+				),
+			}, TestVector{
+				key: [
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+				],
+				nonce: [ 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 ],
+				keystream: vec!(
+					0xef, 0x3f, 0xdf, 0xd6, 0xc6, 0x15, 0x78, 0xfb,
+					0xf5, 0xcf, 0x35, 0xbd, 0x3d, 0xd3, 0x3b, 0x80,
+					0x09, 0x63, 0x16, 0x34, 0xd2, 0x1e, 0x42, 0xac,
+					0x33, 0x96, 0x0b, 0xd1, 0x38, 0xe5, 0x0d, 0x32,
+					0x11, 0x1e, 0x4c, 0xaf, 0x23, 0x7e, 0xe5, 0x3c,
+					0xa8, 0xad, 0x64, 0x26, 0x19, 0x4a, 0x88, 0x54,
+					0x5d, 0xdc, 0x49, 0x7a, 0x0b, 0x46, 0x6e, 0x7d,
+					0x6b, 0xbd, 0xb0, 0x04, 0x1b, 0x2f, 0x58, 0x6b,
+				),
+			}, TestVector{
+				key: [
+					0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+					0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+					0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+					0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+				],
+				nonce: [ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07 ],
+				keystream: vec!(
+					0xf7, 0x98, 0xa1, 0x89, 0xf1, 0x95, 0xe6, 0x69,
+					0x82, 0x10, 0x5f, 0xfb, 0x64, 0x0b, 0xb7, 0x75,
+					0x7f, 0x57, 0x9d, 0xa3, 0x16, 0x02, 0xfc, 0x93,
+					0xec, 0x01, 0xac, 0x56, 0xf8, 0x5a, 0xc3, 0xc1,
+					0x34, 0xa4, 0x54, 0x7b, 0x73, 0x3b, 0x46, 0x41,
+					0x30, 0x42, 0xc9, 0x44, 0x00, 0x49, 0x17, 0x69,
+					0x05, 0xd3, 0xbe, 0x59, 0xea, 0x1c, 0x53, 0xf1,
+					0x59, 0x16, 0x15, 0x5c, 0x2b, 0xe8, 0x24, 0x1a,
+					0x38, 0x00, 0x8b, 0x9a, 0x26, 0xbc, 0x35, 0x94,
+					0x1e, 0x24, 0x44, 0x17, 0x7c, 0x8a, 0xde, 0x66,
+					0x89, 0xde, 0x95, 0x26, 0x49, 0x86, 0xd9, 0x58,
+					0x89, 0xfb, 0x60, 0xe8, 0x46, 0x29, 0xc9, 0xbd,
+					0x9a, 0x5a, 0xcb, 0x1c, 0xc1, 0x18, 0xbe, 0x56,
+					0x3e, 0xb9, 0xb3, 0xa4, 0xa4, 0x72, 0xf8, 0x2e,
+					0x09, 0xa7, 0xe7, 0x78, 0x49, 0x2b, 0x56, 0x2e,
+					0xf7, 0x13, 0x0e, 0x88, 0xdf, 0xe0, 0x31, 0xc7,
+					0x9d, 0xb9, 0xd4, 0xf7, 0xc7, 0xa8, 0x99, 0x15,
+					0x1b, 0x9a, 0x47, 0x50, 0x32, 0xb6, 0x3f, 0xc3,
+					0x85, 0x24, 0x5f, 0xe0, 0x54, 0xe3, 0xdd, 0x5a,
+					0x97, 0xa5, 0xf5, 0x76, 0xfe, 0x06, 0x40, 0x25,
+					0xd3, 0xce, 0x04, 0x2c, 0x56, 0x6a, 0xb2, 0xc5,
+					0x07, 0xb1, 0x38, 0xdb, 0x85, 0x3e, 0x3d, 0x69,
+					0x59, 0x66, 0x09, 0x96, 0x54, 0x6c, 0xc9, 0xc4,
+					0xa6, 0xea, 0xfd, 0xc7, 0x77, 0xc0, 0x40, 0xd7,
+					0x0e, 0xaf, 0x46, 0xf7, 0x6d, 0xad, 0x39, 0x79,
+					0xe5, 0xc5, 0x36, 0x0c, 0x33, 0x17, 0x16, 0x6a,
+					0x1c, 0x89, 0x4c, 0x94, 0xa3, 0x71, 0x87, 0x6a,
+					0x94, 0xdf, 0x76, 0x28, 0xfe, 0x4e, 0xaa, 0xf2,
+					0xcc, 0xb2, 0x7d, 0x5a, 0xaa, 0xe0, 0xad, 0x7a,
+					0xd0, 0xf9, 0xd4, 0xb6, 0xad, 0x3b, 0x54, 0x09,
+					0x87, 0x46, 0xd4, 0x52, 0x4d, 0x38, 0x40, 0x7a,
+					0x6d, 0xeb, 0x3a, 0xb7, 0x8f, 0xab, 0x78, 0xc9,
+				),
+			},
+		);
+
+		for tv in test_vectors.iter() {
+			let mut c = ChaCha20::new(&tv.key, &tv.nonce);
+			let input: Vec<u8> = repeat(0).take(tv.keystream.len()).collect();
+			let mut output: Vec<u8> = repeat(0).take(input.len()).collect();
+			c.process(&input[..], &mut output[..]);
+			assert_eq!(output, tv.keystream);
+		}
+	}
+
+	#[test]
+	fn test_chacha20_256_tls_vectors_96_nonce() {
+		struct TestVector {
+			key:   [u8; 32],
+			nonce: [u8; 12],
+			keystream: Vec<u8>,
+		};
+		// taken from http://tools.ietf.org/html/draft-agl-tls-chacha20poly1305-04
+		let test_vectors = vec!(
+			TestVector{
+				key: [
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+				],
+				nonce: [ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 ],
+				keystream: vec!(
+					0x76, 0xb8, 0xe0, 0xad, 0xa0, 0xf1, 0x3d, 0x90,
+					0x40, 0x5d, 0x6a, 0xe5, 0x53, 0x86, 0xbd, 0x28,
+					0xbd, 0xd2, 0x19, 0xb8, 0xa0, 0x8d, 0xed, 0x1a,
+					0xa8, 0x36, 0xef, 0xcc, 0x8b, 0x77, 0x0d, 0xc7,
+					0xda, 0x41, 0x59, 0x7c, 0x51, 0x57, 0x48, 0x8d,
+					0x77, 0x24, 0xe0, 0x3f, 0xb8, 0xd8, 0x4a, 0x37,
+					0x6a, 0x43, 0xb8, 0xf4, 0x15, 0x18, 0xa1, 0x1c,
+					0xc3, 0x87, 0xb6, 0x69, 0xb2, 0xee, 0x65, 0x86,
+				),
+			}, TestVector{
+				key: [
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
+				],
+				nonce: [ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 ],
+				keystream: vec!(
+					0x45, 0x40, 0xf0, 0x5a, 0x9f, 0x1f, 0xb2, 0x96,
+					0xd7, 0x73, 0x6e, 0x7b, 0x20, 0x8e, 0x3c, 0x96,
+					0xeb, 0x4f, 0xe1, 0x83, 0x46, 0x88, 0xd2, 0x60,
+					0x4f, 0x45, 0x09, 0x52, 0xed, 0x43, 0x2d, 0x41,
+					0xbb, 0xe2, 0xa0, 0xb6, 0xea, 0x75, 0x66, 0xd2,
+					0xa5, 0xd1, 0xe7, 0xe2, 0x0d, 0x42, 0xaf, 0x2c,
+					0x53, 0xd7, 0x92, 0xb1, 0xc4, 0x3f, 0xea, 0x81,
+					0x7e, 0x9a, 0xd2, 0x75, 0xae, 0x54, 0x69, 0x63,
+				),
+			}, TestVector{
+				key: [
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+				],
+				nonce: [ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 ],
+				keystream: vec!(
+					0xde, 0x9c, 0xba, 0x7b, 0xf3, 0xd6, 0x9e, 0xf5,
+					0xe7, 0x86, 0xdc, 0x63, 0x97, 0x3f, 0x65, 0x3a,
+					0x0b, 0x49, 0xe0, 0x15, 0xad, 0xbf, 0xf7, 0x13,
+					0x4f, 0xcb, 0x7d, 0xf1, 0x37, 0x82, 0x10, 0x31,
+					0xe8, 0x5a, 0x05, 0x02, 0x78, 0xa7, 0x08, 0x45,
+					0x27, 0x21, 0x4f, 0x73, 0xef, 0xc7, 0xfa, 0x5b,
+					0x52, 0x77, 0x06, 0x2e, 0xb7, 0xa0, 0x43, 0x3e,
+					0x44, 0x5f, 0x41, 0xe3,
+				),
+			}, TestVector{
+				key: [
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+					0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+				],
+				nonce: [ 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 ],
+				keystream: vec!(
+					0xef, 0x3f, 0xdf, 0xd6, 0xc6, 0x15, 0x78, 0xfb,
+					0xf5, 0xcf, 0x35, 0xbd, 0x3d, 0xd3, 0x3b, 0x80,
+					0x09, 0x63, 0x16, 0x34, 0xd2, 0x1e, 0x42, 0xac,
+					0x33, 0x96, 0x0b, 0xd1, 0x38, 0xe5, 0x0d, 0x32,
+					0x11, 0x1e, 0x4c, 0xaf, 0x23, 0x7e, 0xe5, 0x3c,
+					0xa8, 0xad, 0x64, 0x26, 0x19, 0x4a, 0x88, 0x54,
+					0x5d, 0xdc, 0x49, 0x7a, 0x0b, 0x46, 0x6e, 0x7d,
+					0x6b, 0xbd, 0xb0, 0x04, 0x1b, 0x2f, 0x58, 0x6b,
+				),
+			}, TestVector{
+				key: [
+					0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+					0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+					0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+					0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+				],
+				nonce: [0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07 ],
+				keystream: vec!(
+					0xf7, 0x98, 0xa1, 0x89, 0xf1, 0x95, 0xe6, 0x69,
+					0x82, 0x10, 0x5f, 0xfb, 0x64, 0x0b, 0xb7, 0x75,
+					0x7f, 0x57, 0x9d, 0xa3, 0x16, 0x02, 0xfc, 0x93,
+					0xec, 0x01, 0xac, 0x56, 0xf8, 0x5a, 0xc3, 0xc1,
+					0x34, 0xa4, 0x54, 0x7b, 0x73, 0x3b, 0x46, 0x41,
+					0x30, 0x42, 0xc9, 0x44, 0x00, 0x49, 0x17, 0x69,
+					0x05, 0xd3, 0xbe, 0x59, 0xea, 0x1c, 0x53, 0xf1,
+					0x59, 0x16, 0x15, 0x5c, 0x2b, 0xe8, 0x24, 0x1a,
+					0x38, 0x00, 0x8b, 0x9a, 0x26, 0xbc, 0x35, 0x94,
+					0x1e, 0x24, 0x44, 0x17, 0x7c, 0x8a, 0xde, 0x66,
+					0x89, 0xde, 0x95, 0x26, 0x49, 0x86, 0xd9, 0x58,
+					0x89, 0xfb, 0x60, 0xe8, 0x46, 0x29, 0xc9, 0xbd,
+					0x9a, 0x5a, 0xcb, 0x1c, 0xc1, 0x18, 0xbe, 0x56,
+					0x3e, 0xb9, 0xb3, 0xa4, 0xa4, 0x72, 0xf8, 0x2e,
+					0x09, 0xa7, 0xe7, 0x78, 0x49, 0x2b, 0x56, 0x2e,
+					0xf7, 0x13, 0x0e, 0x88, 0xdf, 0xe0, 0x31, 0xc7,
+					0x9d, 0xb9, 0xd4, 0xf7, 0xc7, 0xa8, 0x99, 0x15,
+					0x1b, 0x9a, 0x47, 0x50, 0x32, 0xb6, 0x3f, 0xc3,
+					0x85, 0x24, 0x5f, 0xe0, 0x54, 0xe3, 0xdd, 0x5a,
+					0x97, 0xa5, 0xf5, 0x76, 0xfe, 0x06, 0x40, 0x25,
+					0xd3, 0xce, 0x04, 0x2c, 0x56, 0x6a, 0xb2, 0xc5,
+					0x07, 0xb1, 0x38, 0xdb, 0x85, 0x3e, 0x3d, 0x69,
+					0x59, 0x66, 0x09, 0x96, 0x54, 0x6c, 0xc9, 0xc4,
+					0xa6, 0xea, 0xfd, 0xc7, 0x77, 0xc0, 0x40, 0xd7,
+					0x0e, 0xaf, 0x46, 0xf7, 0x6d, 0xad, 0x39, 0x79,
+					0xe5, 0xc5, 0x36, 0x0c, 0x33, 0x17, 0x16, 0x6a,
+					0x1c, 0x89, 0x4c, 0x94, 0xa3, 0x71, 0x87, 0x6a,
+					0x94, 0xdf, 0x76, 0x28, 0xfe, 0x4e, 0xaa, 0xf2,
+					0xcc, 0xb2, 0x7d, 0x5a, 0xaa, 0xe0, 0xad, 0x7a,
+					0xd0, 0xf9, 0xd4, 0xb6, 0xad, 0x3b, 0x54, 0x09,
+					0x87, 0x46, 0xd4, 0x52, 0x4d, 0x38, 0x40, 0x7a,
+					0x6d, 0xeb, 0x3a, 0xb7, 0x8f, 0xab, 0x78, 0xc9,
+				),
+			},
+		);
+
+		for tv in test_vectors.iter() {
+			let mut c = ChaCha20::new(&tv.key, &tv.nonce);
+			let input: Vec<u8> = repeat(0).take(tv.keystream.len()).collect();
+			let mut output: Vec<u8> = repeat(0).take(input.len()).collect();
+			c.process(&input[..], &mut output[..]);
+			assert_eq!(output, tv.keystream);
+		}
+	}
+}
diff --git a/src/util/chacha20poly1305rfc.rs b/src/util/chacha20poly1305rfc.rs
index 1aeaf61d2..3468e576d 100644
--- a/src/util/chacha20poly1305rfc.rs
+++ b/src/util/chacha20poly1305rfc.rs
@@ -12,19 +12,19 @@
 
 #[cfg(not(feature = "fuzztarget"))]
 mod real_chachapoly {
+	use util::chacha20::ChaCha20;
+
 	use crypto::aead::{AeadEncryptor,AeadDecryptor};
 	use crypto::symmetriccipher::SynchronousStreamCipher;
-	use crypto::poly1305::Poly1305;
 	use crypto::mac::Mac;
 	use crypto::util::fixed_time_eq;
-
-	pub use crypto::chacha20::ChaCha20;
+	use crypto::poly1305::Poly1305;
 
 	use util::byte_utils;
 
 	#[derive(Clone, Copy)]
 	pub struct ChaCha20Poly1305RFC {
-		cipher  : ChaCha20,
+		cipher: ChaCha20,
 		mac: Poly1305,
 		finished: bool,
 		data_len: usize,
@@ -105,12 +105,11 @@ mod real_chachapoly {
 	}
 }
 #[cfg(not(feature = "fuzztarget"))]
-pub use self::real_chachapoly::{ChaCha20Poly1305RFC, ChaCha20};
+pub use self::real_chachapoly::ChaCha20Poly1305RFC;
 
 #[cfg(feature = "fuzztarget")]
 mod fuzzy_chachapoly {
 	use crypto::aead::{AeadEncryptor,AeadDecryptor};
-	use crypto::symmetriccipher::SynchronousStreamCipher;
 
 	#[derive(Clone, Copy)]
 	pub struct ChaCha20Poly1305RFC {
@@ -157,22 +156,6 @@ mod fuzzy_chachapoly {
 			true
 		}
 	}
-
-	pub struct ChaCha20 {}
-
-	impl ChaCha20 {
-		pub fn new(key: &[u8], nonce: &[u8]) -> ChaCha20 {
-			assert!(key.len() == 16 || key.len() == 32);
-			assert!(nonce.len() == 8 || nonce.len() == 12);
-			Self {}
-		}
-	}
-
-	impl SynchronousStreamCipher for ChaCha20 {
-		fn process(&mut self, input: &[u8], output: &mut [u8]) {
-			output.copy_from_slice(input);
-		}
-	}
 }
 #[cfg(feature = "fuzztarget")]
-pub use self::fuzzy_chachapoly::{ChaCha20Poly1305RFC, ChaCha20};
+pub use self::fuzzy_chachapoly::ChaCha20Poly1305RFC;
diff --git a/src/util/mod.rs b/src/util/mod.rs
index 78886f11e..c31d7be48 100644
--- a/src/util/mod.rs
+++ b/src/util/mod.rs
@@ -5,6 +5,7 @@ pub mod errors;
 pub mod ser;
 
 pub(crate) mod byte_utils;
+pub(crate) mod chacha20;
 pub(crate) mod chacha20poly1305rfc;
 pub(crate) mod internal_traits;
 pub(crate) mod rng;