use crate::chacha20::ChaCha;
use crate::constant_time::{Choice, CtEqual};
use crate::cryptoutil::write_u64_le;
use crate::mac::Mac;
use crate::poly1305::Poly1305;
#[derive(Clone)]
pub struct Context<const ROUNDS: usize> {
cipher: ChaCha<ROUNDS>,
mac: Poly1305,
aad_len: u64,
data_len: u64,
}
#[derive(Clone)]
pub struct ContextEncryption<const ROUNDS: usize>(Context<ROUNDS>);
#[derive(Clone)]
pub struct ContextDecryption<const ROUNDS: usize>(Context<ROUNDS>);
#[derive(Debug, Clone)]
pub struct Tag(pub [u8; 16]);
impl CtEqual for &Tag {
fn ct_eq(self, other: Self) -> Choice {
self.0.ct_eq(&other.0)
}
fn ct_ne(self, b: Self) -> Choice {
self.ct_eq(b).negate()
}
}
impl PartialEq for Tag {
fn eq(&self, other: &Self) -> bool {
self.ct_eq(other).is_true()
}
}
impl Eq for Tag {}
impl<const ROUNDS: usize> Context<ROUNDS> {
pub fn new(key: &[u8], nonce: &[u8]) -> Self {
assert!(key.len() == 16 || key.len() == 32);
assert!(nonce.len() == 8 || nonce.len() == 12);
let mut cipher = ChaCha::new(key, nonce);
let mut mac_key = [0u8; 64];
let zero_key = [0u8; 64];
cipher.process(&zero_key, &mut mac_key);
let mac = Poly1305::new(&mac_key[..32]);
Context {
cipher: cipher,
mac: mac,
aad_len: 0,
data_len: 0,
}
}
fn add_encrypted(&mut self, encrypted: &[u8]) {
self.mac.input(encrypted);
self.data_len += encrypted.len() as u64;
}
pub fn add_data(&mut self, aad: &[u8]) {
self.aad_len += aad.len() as u64;
self.mac.input(aad);
}
pub fn to_encryption(mut self) -> ContextEncryption<ROUNDS> {
pad16(&mut self.mac, self.aad_len);
ContextEncryption(self)
}
pub fn to_decryption(mut self) -> ContextDecryption<ROUNDS> {
pad16(&mut self.mac, self.aad_len);
ContextDecryption(self)
}
}
fn finalize_raw<const ROUNDS: usize>(inner: &mut Context<ROUNDS>) -> [u8; 16] {
let mut len_buf = [0u8; 16];
pad16(&mut inner.mac, inner.data_len);
write_u64_le(&mut len_buf[0..8], inner.aad_len);
write_u64_le(&mut len_buf[8..16], inner.data_len);
inner.mac.input(&len_buf);
inner.mac.raw_result(&mut len_buf);
len_buf
}
impl<const ROUNDS: usize> ContextEncryption<ROUNDS> {
pub fn encrypt_mut(&mut self, buf: &mut [u8]) {
self.0.cipher.process_mut(buf);
self.0.add_encrypted(buf);
}
pub fn encrypt(&mut self, input: &[u8], output: &mut [u8]) {
assert_eq!(input.len(), output.len());
self.0.cipher.process(input, output);
self.0.add_encrypted(output);
}
#[must_use]
pub fn finalize(mut self) -> Tag {
let tag = finalize_raw(&mut self.0);
Tag(tag)
}
}
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum DecryptionResult {
Match,
MisMatch,
}
impl<const ROUNDS: usize> ContextDecryption<ROUNDS> {
pub fn decrypt_mut(&mut self, buf: &mut [u8]) {
self.0.add_encrypted(buf);
self.0.cipher.process_mut(buf);
}
pub fn decrypt(&mut self, input: &[u8], output: &mut [u8]) {
assert_eq!(input.len(), output.len());
self.0.add_encrypted(input);
self.0.cipher.process(input, output);
}
#[must_use = "if the result is not checked, then the data will not be verified against tempering"]
pub fn finalize(mut self, expected_tag: &Tag) -> DecryptionResult {
let got_tag = Tag(finalize_raw(&mut self.0));
if &got_tag == expected_tag {
DecryptionResult::Match
} else {
DecryptionResult::MisMatch
}
}
}
#[derive(Clone)]
pub struct ChaChaPoly1305<const ROUNDS: usize> {
finished: bool,
context: Context<ROUNDS>,
}
fn pad16(mac: &mut Poly1305, len: u64) {
if (len % 16) != 0 {
let padding = [0u8; 15];
let sz = 16 - (len % 16) as usize;
mac.input(&padding[0..sz]);
}
}
pub type ChaCha20Poly1305 = ChaChaPoly1305<20>;
impl<const ROUNDS: usize> ChaChaPoly1305<ROUNDS> {
pub fn new(key: &[u8], nonce: &[u8], aad: &[u8]) -> Self {
let mut context = Context::new(key, nonce);
context.add_data(aad);
ChaChaPoly1305 {
context: context,
finished: false,
}
}
pub fn encrypt(&mut self, input: &[u8], output: &mut [u8], out_tag: &mut [u8]) {
assert!(input.len() == output.len());
assert!(!self.finished);
assert!(out_tag.len() == 16);
self.finished = true;
let mut ctx = self.context.clone().to_encryption();
ctx.encrypt(input, output);
let Tag(tag) = ctx.finalize();
out_tag.copy_from_slice(&tag[..])
}
pub fn decrypt(&mut self, input: &[u8], output: &mut [u8], tag: &[u8]) -> bool {
assert!(tag.len() == 16);
assert!(input.len() == output.len());
assert!(!self.finished);
self.finished = true;
let mut tag_data = [0u8; 16];
tag_data.copy_from_slice(tag);
let mut ctx = self.context.clone().to_decryption();
ctx.decrypt(input, output);
ctx.finalize(&Tag(tag_data)) == DecryptionResult::Match
}
}
#[cfg(test)]
mod test {
use super::ChaCha20Poly1305;
struct TestVector {
key: [u8; 32],
nonce: &'static [u8],
tag: [u8; 16],
plain_text: &'static [u8],
cipher_text: &'static [u8],
aad: &'static [u8],
}
fn test_vector(v: &TestVector) {
let mut tag = [0u8; 16];
let mut ciphertext = vec![0u8; v.cipher_text.len()];
let mut context = ChaCha20Poly1305::new(&v.key, &v.nonce, &v.aad);
let mut dcontext = context.clone();
context.encrypt(&v.plain_text, &mut ciphertext, &mut tag[..]);
assert_eq!(&ciphertext[..], &v.cipher_text[..]);
assert_eq!(&tag[..], &v.tag[..]);
let mut output = vec![0u8; v.plain_text.len()];
assert_eq!(dcontext.decrypt(&ciphertext, &mut output, &v.tag[..]), true);
assert_eq!(&output[..], &v.plain_text[..]);
}
#[test]
fn test_vectors() {
let tests = [
TestVector {
key: [
0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c,
0x8d, 0x8e, 0x8f, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99,
0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
],
nonce: &[
0x07, 0x00, 0x00, 0x00, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
],
plain_text: &[
0x4c, 0x61, 0x64, 0x69, 0x65, 0x73, 0x20, 0x61, 0x6e, 0x64, 0x20, 0x47, 0x65,
0x6e, 0x74, 0x6c, 0x65, 0x6d, 0x65, 0x6e, 0x20, 0x6f, 0x66, 0x20, 0x74, 0x68,
0x65, 0x20, 0x63, 0x6c, 0x61, 0x73, 0x73, 0x20, 0x6f, 0x66, 0x20, 0x27, 0x39,
0x39, 0x3a, 0x20, 0x49, 0x66, 0x20, 0x49, 0x20, 0x63, 0x6f, 0x75, 0x6c, 0x64,
0x20, 0x6f, 0x66, 0x66, 0x65, 0x72, 0x20, 0x79, 0x6f, 0x75, 0x20, 0x6f, 0x6e,
0x6c, 0x79, 0x20, 0x6f, 0x6e, 0x65, 0x20, 0x74, 0x69, 0x70, 0x20, 0x66, 0x6f,
0x72, 0x20, 0x74, 0x68, 0x65, 0x20, 0x66, 0x75, 0x74, 0x75, 0x72, 0x65, 0x2c,
0x20, 0x73, 0x75, 0x6e, 0x73, 0x63, 0x72, 0x65, 0x65, 0x6e, 0x20, 0x77, 0x6f,
0x75, 0x6c, 0x64, 0x20, 0x62, 0x65, 0x20, 0x69, 0x74, 0x2e,
],
aad: &[
0x50, 0x51, 0x52, 0x53, 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7,
],
cipher_text: &[
0xd3, 0x1a, 0x8d, 0x34, 0x64, 0x8e, 0x60, 0xdb, 0x7b, 0x86, 0xaf, 0xbc, 0x53,
0xef, 0x7e, 0xc2, 0xa4, 0xad, 0xed, 0x51, 0x29, 0x6e, 0x08, 0xfe, 0xa9, 0xe2,
0xb5, 0xa7, 0x36, 0xee, 0x62, 0xd6, 0x3d, 0xbe, 0xa4, 0x5e, 0x8c, 0xa9, 0x67,
0x12, 0x82, 0xfa, 0xfb, 0x69, 0xda, 0x92, 0x72, 0x8b, 0x1a, 0x71, 0xde, 0x0a,
0x9e, 0x06, 0x0b, 0x29, 0x05, 0xd6, 0xa5, 0xb6, 0x7e, 0xcd, 0x3b, 0x36, 0x92,
0xdd, 0xbd, 0x7f, 0x2d, 0x77, 0x8b, 0x8c, 0x98, 0x03, 0xae, 0xe3, 0x28, 0x09,
0x1b, 0x58, 0xfa, 0xb3, 0x24, 0xe4, 0xfa, 0xd6, 0x75, 0x94, 0x55, 0x85, 0x80,
0x8b, 0x48, 0x31, 0xd7, 0xbc, 0x3f, 0xf4, 0xde, 0xf0, 0x8e, 0x4b, 0x7a, 0x9d,
0xe5, 0x76, 0xd2, 0x65, 0x86, 0xce, 0xc6, 0x4b, 0x61, 0x16,
],
tag: [
0x1a, 0xe1, 0x0b, 0x59, 0x4f, 0x09, 0xe2, 0x6a, 0x7e, 0x90, 0x2e, 0xcb, 0xd0,
0x60, 0x06, 0x91,
],
},
TestVector {
key: [
0x1c, 0x92, 0x40, 0xa5, 0xeb, 0x55, 0xd3, 0x8a, 0xf3, 0x33, 0x88, 0x86, 0x04,
0xf6, 0xb5, 0xf0, 0x47, 0x39, 0x17, 0xc1, 0x40, 0x2b, 0x80, 0x09, 0x9d, 0xca,
0x5c, 0xbc, 0x20, 0x70, 0x75, 0xc0,
],
nonce: &[
0x00, 0x00, 0x00, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
],
tag: [
0xee, 0xad, 0x9d, 0x67, 0x89, 0x0c, 0xbb, 0x22, 0x39, 0x23, 0x36, 0xfe, 0xa1,
0x85, 0x1f, 0x38,
],
plain_text: &[
0x49, 0x6e, 0x74, 0x65, 0x72, 0x6e, 0x65, 0x74, 0x2d, 0x44, 0x72, 0x61, 0x66,
0x74, 0x73, 0x20, 0x61, 0x72, 0x65, 0x20, 0x64, 0x72, 0x61, 0x66, 0x74, 0x20,
0x64, 0x6f, 0x63, 0x75, 0x6d, 0x65, 0x6e, 0x74, 0x73, 0x20, 0x76, 0x61, 0x6c,
0x69, 0x64, 0x20, 0x66, 0x6f, 0x72, 0x20, 0x61, 0x20, 0x6d, 0x61, 0x78, 0x69,
0x6d, 0x75, 0x6d, 0x20, 0x6f, 0x66, 0x20, 0x73, 0x69, 0x78, 0x20, 0x6d, 0x6f,
0x6e, 0x74, 0x68, 0x73, 0x20, 0x61, 0x6e, 0x64, 0x20, 0x6d, 0x61, 0x79, 0x20,
0x62, 0x65, 0x20, 0x75, 0x70, 0x64, 0x61, 0x74, 0x65, 0x64, 0x2c, 0x20, 0x72,
0x65, 0x70, 0x6c, 0x61, 0x63, 0x65, 0x64, 0x2c, 0x20, 0x6f, 0x72, 0x20, 0x6f,
0x62, 0x73, 0x6f, 0x6c, 0x65, 0x74, 0x65, 0x64, 0x20, 0x62, 0x79, 0x20, 0x6f,
0x74, 0x68, 0x65, 0x72, 0x20, 0x64, 0x6f, 0x63, 0x75, 0x6d, 0x65, 0x6e, 0x74,
0x73, 0x20, 0x61, 0x74, 0x20, 0x61, 0x6e, 0x79, 0x20, 0x74, 0x69, 0x6d, 0x65,
0x2e, 0x20, 0x49, 0x74, 0x20, 0x69, 0x73, 0x20, 0x69, 0x6e, 0x61, 0x70, 0x70,
0x72, 0x6f, 0x70, 0x72, 0x69, 0x61, 0x74, 0x65, 0x20, 0x74, 0x6f, 0x20, 0x75,
0x73, 0x65, 0x20, 0x49, 0x6e, 0x74, 0x65, 0x72, 0x6e, 0x65, 0x74, 0x2d, 0x44,
0x72, 0x61, 0x66, 0x74, 0x73, 0x20, 0x61, 0x73, 0x20, 0x72, 0x65, 0x66, 0x65,
0x72, 0x65, 0x6e, 0x63, 0x65, 0x20, 0x6d, 0x61, 0x74, 0x65, 0x72, 0x69, 0x61,
0x6c, 0x20, 0x6f, 0x72, 0x20, 0x74, 0x6f, 0x20, 0x63, 0x69, 0x74, 0x65, 0x20,
0x74, 0x68, 0x65, 0x6d, 0x20, 0x6f, 0x74, 0x68, 0x65, 0x72, 0x20, 0x74, 0x68,
0x61, 0x6e, 0x20, 0x61, 0x73, 0x20, 0x2f, 0xe2, 0x80, 0x9c, 0x77, 0x6f, 0x72,
0x6b, 0x20, 0x69, 0x6e, 0x20, 0x70, 0x72, 0x6f, 0x67, 0x72, 0x65, 0x73, 0x73,
0x2e, 0x2f, 0xe2, 0x80, 0x9d,
],
cipher_text: &[
0x64, 0xa0, 0x86, 0x15, 0x75, 0x86, 0x1a, 0xf4, 0x60, 0xf0, 0x62, 0xc7, 0x9b,
0xe6, 0x43, 0xbd, 0x5e, 0x80, 0x5c, 0xfd, 0x34, 0x5c, 0xf3, 0x89, 0xf1, 0x08,
0x67, 0x0a, 0xc7, 0x6c, 0x8c, 0xb2, 0x4c, 0x6c, 0xfc, 0x18, 0x75, 0x5d, 0x43,
0xee, 0xa0, 0x9e, 0xe9, 0x4e, 0x38, 0x2d, 0x26, 0xb0, 0xbd, 0xb7, 0xb7, 0x3c,
0x32, 0x1b, 0x01, 0x00, 0xd4, 0xf0, 0x3b, 0x7f, 0x35, 0x58, 0x94, 0xcf, 0x33,
0x2f, 0x83, 0x0e, 0x71, 0x0b, 0x97, 0xce, 0x98, 0xc8, 0xa8, 0x4a, 0xbd, 0x0b,
0x94, 0x81, 0x14, 0xad, 0x17, 0x6e, 0x00, 0x8d, 0x33, 0xbd, 0x60, 0xf9, 0x82,
0xb1, 0xff, 0x37, 0xc8, 0x55, 0x97, 0x97, 0xa0, 0x6e, 0xf4, 0xf0, 0xef, 0x61,
0xc1, 0x86, 0x32, 0x4e, 0x2b, 0x35, 0x06, 0x38, 0x36, 0x06, 0x90, 0x7b, 0x6a,
0x7c, 0x02, 0xb0, 0xf9, 0xf6, 0x15, 0x7b, 0x53, 0xc8, 0x67, 0xe4, 0xb9, 0x16,
0x6c, 0x76, 0x7b, 0x80, 0x4d, 0x46, 0xa5, 0x9b, 0x52, 0x16, 0xcd, 0xe7, 0xa4,
0xe9, 0x90, 0x40, 0xc5, 0xa4, 0x04, 0x33, 0x22, 0x5e, 0xe2, 0x82, 0xa1, 0xb0,
0xa0, 0x6c, 0x52, 0x3e, 0xaf, 0x45, 0x34, 0xd7, 0xf8, 0x3f, 0xa1, 0x15, 0x5b,
0x00, 0x47, 0x71, 0x8c, 0xbc, 0x54, 0x6a, 0x0d, 0x07, 0x2b, 0x04, 0xb3, 0x56,
0x4e, 0xea, 0x1b, 0x42, 0x22, 0x73, 0xf5, 0x48, 0x27, 0x1a, 0x0b, 0xb2, 0x31,
0x60, 0x53, 0xfa, 0x76, 0x99, 0x19, 0x55, 0xeb, 0xd6, 0x31, 0x59, 0x43, 0x4e,
0xce, 0xbb, 0x4e, 0x46, 0x6d, 0xae, 0x5a, 0x10, 0x73, 0xa6, 0x72, 0x76, 0x27,
0x09, 0x7a, 0x10, 0x49, 0xe6, 0x17, 0xd9, 0x1d, 0x36, 0x10, 0x94, 0xfa, 0x68,
0xf0, 0xff, 0x77, 0x98, 0x71, 0x30, 0x30, 0x5b, 0xea, 0xba, 0x2e, 0xda, 0x04,
0xdf, 0x99, 0x7b, 0x71, 0x4d, 0x6c, 0x6f, 0x2c, 0x29, 0xa6, 0xad, 0x5c, 0xb4,
0x02, 0x2b, 0x02, 0x70, 0x9b,
],
aad: &[
0xf3, 0x33, 0x88, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x4e, 0x91,
],
},
];
for tv in tests.iter() {
test_vector(&tv)
}
}
}
#[cfg(all(test, feature = "with-bench"))]
mod bench {
use super::ChaCha20Poly1305;
use test::Bencher;
#[bench]
pub fn chacha20poly1305_10(bh: &mut Bencher) {
let input = [1u8; 10];
let aad = [3u8; 10];
bh.iter(|| {
let mut cipher = ChaCha20Poly1305::new(&[0; 32], &[0; 8], &aad);
let mut decipher = ChaCha20Poly1305::new(&[0; 32], &[0; 8], &aad);
let mut output = [0u8; 10];
let mut tag = [0u8; 16];
let mut output2 = [0u8; 10];
cipher.encrypt(&input, &mut output, &mut tag);
decipher.decrypt(&output, &mut output2, &tag);
});
bh.bytes = 10u64;
}
#[bench]
pub fn chacha20poly1305_1k(bh: &mut Bencher) {
let input = [1u8; 1024];
let aad = [3u8; 1024];
bh.iter(|| {
let mut cipher = ChaCha20Poly1305::new(&[0; 32], &[0; 8], &aad);
let mut decipher = ChaCha20Poly1305::new(&[0; 32], &[0; 8], &aad);
let mut output = [0u8; 1024];
let mut tag = [0u8; 16];
let mut output2 = [0u8; 1024];
cipher.encrypt(&input, &mut output, &mut tag);
decipher.decrypt(&output, &mut output2, &tag);
});
bh.bytes = 1024u64;
}
#[bench]
pub fn chacha20poly1305_64k(bh: &mut Bencher) {
let input = [1u8; 65536];
let aad = [3u8; 65536];
bh.iter(|| {
let mut cipher = ChaCha20Poly1305::new(&[0; 32], &[0; 8], &aad);
let mut decipher = ChaCha20Poly1305::new(&[0; 32], &[0; 8], &aad);
let mut output = [0u8; 65536];
let mut tag = [0u8; 16];
let mut output2 = [0u8; 65536];
cipher.encrypt(&input, &mut output, &mut tag);
decipher.decrypt(&output, &mut output2, &tag);
});
bh.bytes = 65536u64;
}
}