nim-libp2p/libp2p/crypto/chacha20poly1305.nim

98 lines
2.6 KiB
Nim

# Nim-Libp2p
# Copyright (c) 2023 Status Research & Development GmbH
# Licensed under either of
# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
# * MIT license ([LICENSE-MIT](LICENSE-MIT))
# at your option.
# This file may not be copied, modified, or distributed except according to
# those terms.
## This module integrates BearSSL ChaCha20+Poly1305
##
## This module uses unmodified parts of code from
## BearSSL library <https://bearssl.org/>
## Copyright(C) 2018 Thomas Pornin <pornin@bolet.org>.
# RFC @ https://tools.ietf.org/html/rfc7539
{.push raises: [].}
import bearssl/blockx
from stew/assign2 import assign
from stew/ptrops import baseAddr
const
ChaChaPolyKeySize = 32
ChaChaPolyNonceSize = 12
ChaChaPolyTagSize = 16
type
ChaChaPoly* = object
ChaChaPolyKey* = array[ChaChaPolyKeySize, byte]
ChaChaPolyNonce* = array[ChaChaPolyNonceSize, byte]
ChaChaPolyTag* = array[ChaChaPolyTagSize, byte]
proc intoChaChaPolyKey*(s: openArray[byte]): ChaChaPolyKey =
assert s.len == ChaChaPolyKeySize
assign(result, s)
proc intoChaChaPolyNonce*(s: openArray[byte]): ChaChaPolyNonce =
assert s.len == ChaChaPolyNonceSize
assign(result, s)
proc intoChaChaPolyTag*(s: openArray[byte]): ChaChaPolyTag =
assert s.len == ChaChaPolyTagSize
assign(result, s)
# bearssl allows us to use optimized versions
# this is reconciled at runtime
# we do this in the global scope / module init
proc encrypt*(_: type[ChaChaPoly],
key: ChaChaPolyKey,
nonce: ChaChaPolyNonce,
tag: var ChaChaPolyTag,
data: var openArray[byte],
aad: openArray[byte]) =
let
ad = if aad.len > 0:
unsafeAddr aad[0]
else:
nil
poly1305CtmulRun(
unsafeAddr key[0],
unsafeAddr nonce[0],
baseAddr(data),
uint(data.len),
ad,
uint(aad.len),
baseAddr(tag),
# cast is required to workaround https://github.com/nim-lang/Nim/issues/13905
cast[Chacha20Run](chacha20CtRun),
#[encrypt]# 1.cint)
proc decrypt*(_: type[ChaChaPoly],
key: ChaChaPolyKey,
nonce: ChaChaPolyNonce,
tag: var ChaChaPolyTag,
data: var openArray[byte],
aad: openArray[byte]) =
let
ad = if aad.len > 0:
unsafeAddr aad[0]
else:
nil
poly1305CtmulRun(
unsafeAddr key[0],
unsafeAddr nonce[0],
baseAddr(data),
uint(data.len),
ad,
uint(aad.len),
baseAddr(tag),
# cast is required to workaround https://github.com/nim-lang/Nim/issues/13905
cast[Chacha20Run](chacha20CtRun),
#[decrypt]# 0.cint)