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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
use std::ffi::c_void;
use prio::vdaf::prg::{Prg, SeedStream};
extern "C" {
pub fn dapStartCmac(aSeed: *mut u8) -> *mut c_void;
pub fn dapUpdateCmac(aContext: *mut c_void, aData: *const u8, aDataLen: u32);
pub fn dapFinalizeCmac(aContext: *mut c_void, aMacOutput: *mut u8);
pub fn dapReleaseCmac(aContext: *mut c_void);
pub fn dapStartAesCtr(aKey: *const u8) -> *mut c_void;
pub fn dapCtrFillBuffer(aContext: *mut c_void, aBuffer: *mut u8, aBufferSize: i32);
pub fn dapReleaseCtrCtx(aContext: *mut c_void);
}
#[derive(Clone, Debug)]
pub struct PrgAes128Alt {
nss_context: *mut c_void,
}
impl Prg<16> for PrgAes128Alt {
type SeedStream = SeedStreamAes128Alt;
fn init(seed_bytes: &[u8; 16]) -> Self {
let mut my_seed_bytes = *seed_bytes;
let ctx = unsafe { dapStartCmac(my_seed_bytes.as_mut_ptr()) };
assert!(!ctx.is_null());
Self { nss_context: ctx }
}
fn update(&mut self, data: &[u8]) {
unsafe {
dapUpdateCmac(
self.nss_context,
data.as_ptr(),
u32::try_from(data.len()).unwrap(),
);
}
}
fn into_seed_stream(self) -> Self::SeedStream {
// finish the MAC and create a new random data stream using the result as key and 0 as IV for AES-CTR
let mut key = [0u8; 16];
unsafe {
dapFinalizeCmac(self.nss_context, key.as_mut_ptr());
}
SeedStreamAes128Alt::new(&mut key, &[0; 16])
}
}
impl Drop for PrgAes128Alt {
fn drop(&mut self) {
unsafe {
dapReleaseCmac(self.nss_context);
}
}
}
pub struct SeedStreamAes128Alt {
nss_context: *mut c_void,
}
impl SeedStreamAes128Alt {
pub(crate) fn new(key: &mut [u8; 16], iv: &[u8; 16]) -> Self {
debug_assert_eq!(iv, &[0; 16]);
let ctx = unsafe { dapStartAesCtr(key.as_ptr()) };
Self { nss_context: ctx }
}
}
impl SeedStream for SeedStreamAes128Alt {
fn fill(&mut self, buf: &mut [u8]) {
unsafe {
dapCtrFillBuffer(
self.nss_context,
buf.as_mut_ptr(),
i32::try_from(buf.len()).unwrap(),
);
}
}
}
impl Drop for SeedStreamAes128Alt {
fn drop(&mut self) {
unsafe { dapReleaseCtrCtx(self.nss_context) };
}
}
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