nim-libp2p/libp2p/crypto/hkdf.nim

41 lines
1.7 KiB
Nim

## 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.
# https://tools.ietf.org/html/rfc5869
{.push raises: [Defect].}
import nimcrypto
import bearssl
type
BearHKDFContext {.importc: "br_hkdf_context", header: "bearssl_kdf.h".} = object
HKDFResult*[len: static int] = array[len, byte]
proc br_hkdf_init(ctx: ptr BearHKDFContext; hashClass: ptr HashClass; salt: pointer; len: csize_t) {.importc: "br_hkdf_init", header: "bearssl_kdf.h", raises: [].}
proc br_hkdf_inject(ctx: ptr BearHKDFContext; ikm: pointer; len: csize_t) {.importc: "br_hkdf_inject", header: "bearssl_kdf.h", raises: [].}
proc br_hkdf_flip(ctx: ptr BearHKDFContext) {.importc: "br_hkdf_flip", header: "bearssl_kdf.h", raises: [].}
proc br_hkdf_produce(ctx: ptr BearHKDFContext; info: pointer; infoLen: csize_t; output: pointer; outputLen: csize_t) {.importc: "br_hkdf_produce", header: "bearssl_kdf.h", raises: [].}
proc hkdf*[T: sha256; len: static int](_: type[T]; salt, ikm, info: openArray[byte]; outputs: var openArray[HKDFResult[len]]) =
var
ctx: BearHKDFContext
br_hkdf_init(
addr ctx, addr sha256Vtable,
if salt.len > 0: unsafeAddr salt[0] else: nil, csize_t(salt.len))
br_hkdf_inject(
addr ctx, if ikm.len > 0: unsafeAddr ikm[0] else: nil, csize_t(ikm.len))
br_hkdf_flip(addr ctx)
for i in 0..outputs.high:
br_hkdf_produce(
addr ctx,
if info.len > 0: unsafeAddr info[0]
else: nil, csize_t(info.len),
addr outputs[i][0], csize_t(outputs[i].len))