Adam Wick
fa872c951a
Previously, we used a little bit of generation to drive a lot of Rust macros. This works, but it's a little confusing to read and write. In addition, we used a lot of implementations with variable timings based on their input, which isn't great for crypto. This is the start of an attempt to just generate all of the relevant Rust code directly, and to use timing-channel resistant implementations for most of the routines.
104 lines
3.5 KiB
Rust
104 lines
3.5 KiB
Rust
/// Modular multiplication of the type.
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pub trait ModMul<T> {
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/// Modular multiplication using the given modulus type. If it's possible,
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/// we suggest using Barrett values, which are much faster than doing
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/// modulo with the number types.
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fn modmul(&self, x: &Self, m: &T) -> Self;
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}
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macro_rules! modmul_impls {
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($name: ident, $dbl: ident, $barrett: ident) => {
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impl ModMul<$name> for $name {
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fn modmul(&self, x: &$name, m: &$name) -> $name {
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let mulres = (self as &$name) * x;
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let bigm = $dbl::from(m);
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let (_, bigres) = mulres.divmod(&bigm);
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$name::from(bigres)
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}
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}
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impl ModMul<$barrett> for $name {
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fn modmul(&self, x: &$name, m: &$barrett) -> $name {
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let mulres = (self as &$name) * x;
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m.reduce(&mulres)
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}
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}
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};
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}
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#[cfg(test)]
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macro_rules! generate_modmul_tests {
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($name: ident, $lname: ident) => {
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#[test]
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fn $lname() {
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generate_modmul_tests!(body $name, $lname);
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}
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};
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(ignore $name: ident, $lname: ident) => {
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#[test]
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#[ignore]
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fn $lname() {
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generate_modmul_tests!(body $name, $lname);
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}
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};
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(body $name: ident, $lname: ident) => {
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let fname = build_test_path("modmul", stringify!($name));
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run_test(fname.to_string(), 6, |case| {
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let (neg0, abytes) = case.get("a").unwrap();
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let (neg1, bbytes) = case.get("b").unwrap();
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let (neg2, mbytes) = case.get("m").unwrap();
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let (neg3, cbytes) = case.get("c").unwrap();
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assert!(!neg0 && !neg1 && !neg2 && !neg3);
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let a = $name::from_bytes(abytes);
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let b = $name::from_bytes(bbytes);
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let m = $name::from_bytes(mbytes);
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let c = $name::from_bytes(cbytes);
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assert_eq!(c, a.modmul(&b, &m));
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});
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};
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}
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#[cfg(test)]
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macro_rules! generate_barrett_modmul_tests {
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($name: ident, $lname: ident, $bname: ident) => {
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#[test]
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fn $lname() {
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generate_barrett_modmul_tests!(body $name, $lname, $bname);
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}
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};
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(ignore $name: ident, $lname: ident, $bname: ident) => {
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#[test]
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#[ignore]
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fn $lname() {
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generate_barrett_modmul_tests!(body $name, $lname, $bname);
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}
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};
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(body $name: ident, $lname: ident, $bname: ident) => {
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let fname = build_test_path("modmul", stringify!($name));
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run_test(fname.to_string(), 6, |case| {
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let (neg0, abytes) = case.get("a").unwrap();
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let (neg1, bbytes) = case.get("b").unwrap();
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let (neg2, mbytes) = case.get("m").unwrap();
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let (neg3, cbytes) = case.get("c").unwrap();
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let (neg4, kbytes) = case.get("k").unwrap();
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let (neg5, ubytes) = case.get("u").unwrap();
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assert!(!neg0 && !neg1 && !neg2 && !neg3 && !neg4 && !neg5);
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let a = $name::from_bytes(abytes);
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let b = $name::from_bytes(bbytes);
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let m = $name::from_bytes(mbytes);
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let c = $name::from_bytes(cbytes);
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let kbig = $name::from_bytes(kbytes);
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let k = usize::from(kbig);
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let mu = $bname::from_bytes(ubytes);
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let bar = $name::new_barrett(k, $bname::from(m), mu);
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if k == a.value.len() {
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assert_eq!(c, a.modmul(&b, &bar));
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}
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});
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};
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} |