nim-libp2p/libp2p/crypto/chacha20poly1305.nim

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## Nim-Libp2p
## Copyright (c) 2020 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
import bearssl
const
ChaChaPolyKeySize = 32
ChaChaPolyNonceSize = 12
ChaChaPolyTagSize = 16
type
ChaChaPoly* = object
ChaChaPolyKey* = array[ChaChaPolyKeySize, byte]
ChaChaPolyNonce* = array[ChaChaPolyNonceSize, byte]
ChaChaPolyTag* = array[ChaChaPolyTagSize, byte]
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proc intoChaChaPolyKey*(s: seq[byte]): ChaChaPolyKey =
assert s.len == ChaChaPolyKeySize
copyMem(addr result[0], unsafeaddr s[0], ChaChaPolyKeySize)
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proc intoChaChaPolyNonce*(s: seq[byte]): ChaChaPolyNonce =
assert s.len == ChaChaPolyNonceSize
copyMem(addr result[0], unsafeaddr s[0], ChaChaPolyNonceSize)
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proc intoChaChaPolyTag*(s: seq[byte]): ChaChaPolyTag =
assert s.len == ChaChaPolyTagSize
copyMem(addr result[0], unsafeaddr s[0], ChaChaPolyTagSize)
# bearssl allows us to use optimized versions
# this is reconciled at runtime
# we do this in the global scope / module init
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template fetchImpl: untyped =
# try for the best first
var
chachapoly_native_impl {.inject.}: Poly1305Run = poly1305CtmulqGet()
chacha_native_impl {.inject.}: Chacha20Run = chacha20Sse2Get()
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# fall back if not available
if chachapoly_native_impl == nil:
chachapoly_native_impl = poly1305CtmulRun
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if chacha_native_impl == nil:
chacha_native_impl = chacha20CtRun
proc encrypt*(_: type[ChaChaPoly],
key: var ChaChaPolyKey,
nonce: var ChaChaPolyNonce,
tag: var ChaChaPolyTag,
data: var openarray[byte],
aad: var openarray[byte]) =
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fetchImpl()
chachapoly_native_impl(
addr key[0],
addr nonce[0],
addr data[0],
data.len,
addr aad[0],
aad.len,
addr tag[0],
chacha_native_impl,
#[encrypt]# 1.cint)
proc decrypt*(_: type[ChaChaPoly],
key: var ChaChaPolyKey,
nonce: var ChaChaPolyNonce,
tag: var ChaChaPolyTag,
data: var openarray[byte],
aad: var openarray[byte]) =
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fetchImpl()
chachapoly_native_impl(
addr key[0],
addr nonce[0],
addr data[0],
data.len,
addr aad[0],
aad.len,
addr tag[0],
chacha_native_impl,
#[decrypt]# 0.cint)