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macro_rules! aead_module (($seal_name:ident,
$open_name:ident,
$seal_detached_name:ident,
$open_detached_name:ident,
$keybytes:expr,
$noncebytes:expr,
$tagbytes:expr) => (
use libc::c_ulonglong;
use crate::randombytes::randombytes_into;
use std::ptr;
/// Number of bytes in a `Key`.
pub const KEYBYTES: usize = $keybytes;
/// Number of bytes in a `Nonce`.
pub const NONCEBYTES: usize = $noncebytes;
/// Number of bytes in an authentication `Tag`.
pub const TAGBYTES: usize = $tagbytes;
new_type! {
/// `Key` for symmetric authenticated encryption with additional data.
///
/// When a `Key` goes out of scope its contents will
/// be zeroed out
secret Key(KEYBYTES);
}
new_type! {
/// `Nonce` for symmetric authenticated encryption with additional data.
nonce Nonce(NONCEBYTES);
}
new_type! {
/// Authentication `Tag` for symmetric authenticated encryption with additional data in
/// detached mode.
public Tag(TAGBYTES);
}
/// `gen_key()` randomly generates a secret key
///
/// THREAD SAFETY: `gen_key()` is thread-safe provided that you have
/// called `rust_sodium::init()` once before using any other function
/// from `rust_sodium`.
pub fn gen_key() -> Key {
let mut k = Key([0u8; KEYBYTES]);
randombytes_into(&mut k.0);
k
}
/// `gen_nonce()` randomly generates a nonce
///
/// THREAD SAFETY: `gen_key()` is thread-safe provided that you have
/// called `rust_sodium::init()` once before using any other function
/// from `rust_sodium`.
pub fn gen_nonce() -> Nonce {
let mut n = Nonce([0u8; NONCEBYTES]);
randombytes_into(&mut n.0);
n
}
/// `seal()` encrypts and authenticates a message `m` together with optional plaintext data `ad`
/// using a secret key `k` and a nonce `n`. It returns a ciphertext `c`.
pub fn seal(m: &[u8], ad: Option<&[u8]>, n: &Nonce, k: &Key) -> Vec<u8> {
let (ad_p, ad_len) = ad.map(|ad| (ad.as_ptr(), ad.len() as c_ulonglong))
.unwrap_or((ptr::null(), 0));
let mut c = Vec::with_capacity(m.len() + TAGBYTES);
let mut clen = c.len() as c_ulonglong;
unsafe {
let _ = $seal_name(
c.as_mut_ptr(),
&mut clen,
m.as_ptr(),
m.len() as c_ulonglong,
ad_p,
ad_len,
ptr::null_mut(),
n.0.as_ptr(),
k.0.as_ptr()
);
c.set_len(clen as usize);
}
c
}
/// `seal_detached()` encrypts and authenticates a message `m` together with optional plaintext data
/// `ad` using a secret key `k` and a nonce `n`.
/// `m` is encrypted in place, so after this function returns it will contain the ciphertext.
/// The detached authentication tag is returned by value.
pub fn seal_detached(m: &mut [u8], ad: Option<&[u8]>, n: &Nonce, k: &Key) -> Tag {
let (ad_p, ad_len) = ad.map(|ad| (ad.as_ptr(), ad.len() as c_ulonglong))
.unwrap_or((ptr::null(), 0));
let mut tag = Tag([0u8; TAGBYTES]);
let mut maclen = TAGBYTES as c_ulonglong;
unsafe {
let _ = $seal_detached_name(
m.as_mut_ptr(),
tag.0.as_mut_ptr(),
&mut maclen,
m.as_ptr(),
m.len() as c_ulonglong,
ad_p,
ad_len,
ptr::null_mut(),
n.0.as_ptr(),
k.0.as_ptr()
);
}
tag
}
/// `open()` verifies and decrypts a ciphertext `c` together with optional plaintext data `ad`
/// using a secret key `k` and a nonce `n`.
/// It returns a plaintext `Ok(m)`.
/// If the ciphertext fails verification, `open()` returns `Err(())`.
pub fn open(c: &[u8], ad: Option<&[u8]>, n: &Nonce, k: &Key) -> Result<Vec<u8>, ()> {
if c.len() < TAGBYTES {
return Err(());
}
let (ad_p, ad_len) = ad.map(|ad| (ad.as_ptr(), ad.len() as c_ulonglong))
.unwrap_or((ptr::null(), 0));
let mut m = Vec::with_capacity(c.len() - TAGBYTES);
let mut mlen = m.len() as c_ulonglong;
unsafe {
let ret =
$open_name(
m.as_mut_ptr(),
&mut mlen,
ptr::null_mut(),
c.as_ptr(),
c.len() as c_ulonglong,
ad_p,
ad_len,
n.0.as_ptr(),
k.0.as_ptr()
);
if ret != 0 {
return Err(());
}
m.set_len(mlen as usize);
}
Ok(m)
}
/// `open_detached()` verifies and decrypts a ciphertext `c` toghether with optional plaintext data
/// `ad` and and authentication tag `tag`, using a secret key `k` and a nonce `n`.
/// `c` is decrypted in place, so if this function is successful it will contain the plaintext.
/// If the ciphertext fails verification, `open_detached()` returns `Err(())`,
/// and the ciphertext is not modified.
pub fn open_detached(
c: &mut [u8],
ad: Option<&[u8]>,
t: &Tag,
n: &Nonce,
k: &Key,
) -> Result<(), ()> {
let (ad_p, ad_len) = ad.map(|ad| (ad.as_ptr(), ad.len() as c_ulonglong))
.unwrap_or((ptr::null(), 0));
let ret = unsafe {
$open_detached_name(
c.as_mut_ptr(),
ptr::null_mut(),
c.as_ptr(),
c.len() as c_ulonglong,
t.0.as_ptr(),
ad_p,
ad_len,
n.0.as_ptr(),
k.0.as_ptr()
)
};
if ret == 0 {
Ok(())
} else {
Err(())
}
}
#[cfg(test)]
mod test_m {
use super::*;
#[test]
fn test_seal_open() {
use crate::randombytes::randombytes;
unwrap!(crate::init());
for i in 0..256usize {
let k = gen_key();
let n = gen_nonce();
let ad = randombytes(i);
let m = randombytes(i);
let c = seal(&m, Some(&ad), &n, &k);
let m2 = unwrap!(open(&c, Some(&ad), &n, &k));
assert_eq!(m, m2);
}
}
#[test]
fn test_seal_open_tamper() {
use crate::randombytes::randombytes;
unwrap!(crate::init());
for i in 0..32usize {
let k = gen_key();
let n = gen_nonce();
let mut ad = randombytes(i);
let m = randombytes(i);
let mut c = seal(&m, Some(&ad), &n, &k);
for j in 0..c.len() {
c[j] ^= 0x20;
let m2 = open(&c, Some(&ad), &n, &k);
c[j] ^= 0x20;
assert!(m2.is_err());
}
for j in 0..ad.len() {
ad[j] ^= 0x20;
let m2 = open(&c, Some(&ad), &n, &k);
ad[j] ^= 0x20;
assert!(m2.is_err());
}
}
}
#[test]
fn test_seal_open_detached() {
use crate::randombytes::randombytes;
unwrap!(crate::init());
for i in 0..256usize {
let k = gen_key();
let n = gen_nonce();
let ad = randombytes(i);
let mut m = randombytes(i);
let m2 = m.clone();
let t = seal_detached(&mut m, Some(&ad), &n, &k);
unwrap!(open_detached(&mut m, Some(&ad), &t, &n, &k));
assert_eq!(m, m2);
}
}
#[test]
fn test_seal_open_detached_tamper() {
use crate::randombytes::randombytes;
unwrap!(crate::init());
for i in 0..32usize {
let k = gen_key();
let n = gen_nonce();
let mut ad = randombytes(i);
let mut m = randombytes(i);
let mut t = seal_detached(&mut m, Some(&ad), &n, &k);
for j in 0..m.len() {
m[j] ^= 0x20;
let r = open_detached(&mut m, Some(&ad), &t, &n, &k);
m[j] ^= 0x20;
assert!(r.is_err());
}
for j in 0..ad.len() {
ad[j] ^= 0x20;
let r = open_detached(&mut m, Some(&ad), &t, &n, &k);
ad[j] ^= 0x20;
assert!(r.is_err());
}
for j in 0..t.0.len() {
t.0[j] ^= 0x20;
let r = open_detached(&mut m, Some(&ad), &t, &n, &k);
t.0[j] ^= 0x20;
assert!(r.is_err());
}
}
}
#[test]
fn test_seal_open_detached_same() {
use crate::randombytes::randombytes;
unwrap!(crate::init());
for i in 0..256usize {
let k = gen_key();
let n = gen_nonce();
let ad = randombytes(i);
let mut m = randombytes(i);
let c = seal(&m, Some(&ad), &n, &k);
let t = seal_detached(&mut m, Some(&ad), &n, &k);
assert_eq!(&c[0..c.len()-TAGBYTES], &m[..]);
assert_eq!(&c[c.len()-TAGBYTES..], &t.0[..]);
let m2 = unwrap!(open(&c, Some(&ad), &n, &k));
unwrap!(open_detached(&mut m, Some(&ad), &t, &n, &k));
assert_eq!(m2, m);
}
}
}
));