189 lines
8.1 KiB
Rust
189 lines
8.1 KiB
Rust
|
//! The `mulX_POLYVAL()` function.
|
||
|
|
|
||
|
|
use crate::Block;
|
||
|
|
|
||
|
|
/// The `mulX_POLYVAL()` function as defined in [RFC 8452 Appendix A][1].
|
||
|
|
///
|
||
|
|
/// Performs a doubling (a.k.a. "multiply by x") over GF(2^128).
|
||
|
|
/// This is useful for implementing GHASH in terms of POLYVAL.
|
||
|
|
///
|
||
|
|
/// [1]: https://tools.ietf.org/html/rfc8452#appendix-A
|
||
|
|
pub fn mulx(block: &Block) -> Block {
|
||
|
|
let mut v = u128::from_le_bytes((*block).into());
|
||
|
|
let v_hi = v >> 127;
|
||
|
|
|
||
|
|
v <<= 1;
|
||
|
|
v ^= v_hi ^ (v_hi << 127) ^ (v_hi << 126) ^ (v_hi << 121);
|
||
|
|
v.to_le_bytes().into()
|
||
|
|
}
|
||
|
|
|
||
|
|
#[cfg(test)]
|
||
|
|
mod tests {
|
||
|
|
use super::{mulx, Block};
|
||
|
|
use hex_literal::hex;
|
||
|
|
|
||
|
|
/// Test vector given in RFC 8452 Appendix A.
|
||
|
|
///
|
||
|
|
/// NOTE: the vector in the RFC actually contains a typo which has been
|
||
|
|
/// reported (and accepted) as RFC errata, so we use the vector from the
|
||
|
|
/// errata instead:
|
||
|
|
///
|
||
|
|
/// <https://www.rfc-editor.org/errata_search.php?rfc=8452>
|
||
|
|
#[test]
|
||
|
|
fn rfc8452_vector() {
|
||
|
|
let input = Block::from(hex!("9c98c04df9387ded828175a92ba652d8"));
|
||
|
|
let expected_output = Block::from(hex!("3931819bf271fada0503eb52574ca572"));
|
||
|
|
let actual_output = mulx(&input);
|
||
|
|
assert_eq!(expected_output, actual_output);
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Test against the `MULX_TEST_VECTORS` given below, which cover the full
|
||
|
|
/// size of a POLYVAL field element.
|
||
|
|
#[test]
|
||
|
|
fn mulx_vectors() {
|
||
|
|
// One
|
||
|
|
let mut r = Block::from(hex!("01000000000000000000000000000000"));
|
||
|
|
|
||
|
|
for vector in MULX_TEST_VECTORS {
|
||
|
|
r = mulx(&r);
|
||
|
|
assert_eq!(&r, Block::from_slice(vector));
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/// `mulX_POLYVAL()` test vectors.
|
||
|
|
///
|
||
|
|
/// These were generated by this crate when in a known-correct state,
|
||
|
|
/// verified by a GHASH implementation based on a POLYVAL core successfully
|
||
|
|
/// passing the NIST test vectors.
|
||
|
|
const MULX_TEST_VECTORS: &[[u8; 16]] = &[
|
||
|
|
hex!("02000000000000000000000000000000"),
|
||
|
|
hex!("04000000000000000000000000000000"),
|
||
|
|
hex!("08000000000000000000000000000000"),
|
||
|
|
hex!("10000000000000000000000000000000"),
|
||
|
|
hex!("20000000000000000000000000000000"),
|
||
|
|
hex!("40000000000000000000000000000000"),
|
||
|
|
hex!("80000000000000000000000000000000"),
|
||
|
|
hex!("00010000000000000000000000000000"),
|
||
|
|
hex!("00020000000000000000000000000000"),
|
||
|
|
hex!("00040000000000000000000000000000"),
|
||
|
|
hex!("00080000000000000000000000000000"),
|
||
|
|
hex!("00100000000000000000000000000000"),
|
||
|
|
hex!("00200000000000000000000000000000"),
|
||
|
|
hex!("00400000000000000000000000000000"),
|
||
|
|
hex!("00800000000000000000000000000000"),
|
||
|
|
hex!("00000100000000000000000000000000"),
|
||
|
|
hex!("00000200000000000000000000000000"),
|
||
|
|
hex!("00000400000000000000000000000000"),
|
||
|
|
hex!("00000800000000000000000000000000"),
|
||
|
|
hex!("00001000000000000000000000000000"),
|
||
|
|
hex!("00002000000000000000000000000000"),
|
||
|
|
hex!("00004000000000000000000000000000"),
|
||
|
|
hex!("00008000000000000000000000000000"),
|
||
|
|
hex!("00000001000000000000000000000000"),
|
||
|
|
hex!("00000002000000000000000000000000"),
|
||
|
|
hex!("00000004000000000000000000000000"),
|
||
|
|
hex!("00000008000000000000000000000000"),
|
||
|
|
hex!("00000010000000000000000000000000"),
|
||
|
|
hex!("00000020000000000000000000000000"),
|
||
|
|
hex!("00000040000000000000000000000000"),
|
||
|
|
hex!("00000080000000000000000000000000"),
|
||
|
|
hex!("00000000010000000000000000000000"),
|
||
|
|
hex!("00000000020000000000000000000000"),
|
||
|
|
hex!("00000000040000000000000000000000"),
|
||
|
|
hex!("00000000080000000000000000000000"),
|
||
|
|
hex!("00000000100000000000000000000000"),
|
||
|
|
hex!("00000000200000000000000000000000"),
|
||
|
|
hex!("00000000400000000000000000000000"),
|
||
|
|
hex!("00000000800000000000000000000000"),
|
||
|
|
hex!("00000000000100000000000000000000"),
|
||
|
|
hex!("00000000000200000000000000000000"),
|
||
|
|
hex!("00000000000400000000000000000000"),
|
||
|
|
hex!("00000000000800000000000000000000"),
|
||
|
|
hex!("00000000001000000000000000000000"),
|
||
|
|
hex!("00000000002000000000000000000000"),
|
||
|
|
hex!("00000000004000000000000000000000"),
|
||
|
|
hex!("00000000008000000000000000000000"),
|
||
|
|
hex!("00000000000001000000000000000000"),
|
||
|
|
hex!("00000000000002000000000000000000"),
|
||
|
|
hex!("00000000000004000000000000000000"),
|
||
|
|
hex!("00000000000008000000000000000000"),
|
||
|
|
hex!("00000000000010000000000000000000"),
|
||
|
|
hex!("00000000000020000000000000000000"),
|
||
|
|
hex!("00000000000040000000000000000000"),
|
||
|
|
hex!("00000000000080000000000000000000"),
|
||
|
|
hex!("00000000000000010000000000000000"),
|
||
|
|
hex!("00000000000000020000000000000000"),
|
||
|
|
hex!("00000000000000040000000000000000"),
|
||
|
|
hex!("00000000000000080000000000000000"),
|
||
|
|
hex!("00000000000000100000000000000000"),
|
||
|
|
hex!("00000000000000200000000000000000"),
|
||
|
|
hex!("00000000000000400000000000000000"),
|
||
|
|
hex!("00000000000000800000000000000000"),
|
||
|
|
hex!("00000000000000000100000000000000"),
|
||
|
|
hex!("00000000000000000200000000000000"),
|
||
|
|
hex!("00000000000000000400000000000000"),
|
||
|
|
hex!("00000000000000000800000000000000"),
|
||
|
|
hex!("00000000000000001000000000000000"),
|
||
|
|
hex!("00000000000000002000000000000000"),
|
||
|
|
hex!("00000000000000004000000000000000"),
|
||
|
|
hex!("00000000000000008000000000000000"),
|
||
|
|
hex!("00000000000000000001000000000000"),
|
||
|
|
hex!("00000000000000000002000000000000"),
|
||
|
|
hex!("00000000000000000004000000000000"),
|
||
|
|
hex!("00000000000000000008000000000000"),
|
||
|
|
hex!("00000000000000000010000000000000"),
|
||
|
|
hex!("00000000000000000020000000000000"),
|
||
|
|
hex!("00000000000000000040000000000000"),
|
||
|
|
hex!("00000000000000000080000000000000"),
|
||
|
|
hex!("00000000000000000000010000000000"),
|
||
|
|
hex!("00000000000000000000020000000000"),
|
||
|
|
hex!("00000000000000000000040000000000"),
|
||
|
|
hex!("00000000000000000000080000000000"),
|
||
|
|
hex!("00000000000000000000100000000000"),
|
||
|
|
hex!("00000000000000000000200000000000"),
|
||
|
|
hex!("00000000000000000000400000000000"),
|
||
|
|
hex!("00000000000000000000800000000000"),
|
||
|
|
hex!("00000000000000000000000100000000"),
|
||
|
|
hex!("00000000000000000000000200000000"),
|
||
|
|
hex!("00000000000000000000000400000000"),
|
||
|
|
hex!("00000000000000000000000800000000"),
|
||
|
|
hex!("00000000000000000000001000000000"),
|
||
|
|
hex!("00000000000000000000002000000000"),
|
||
|
|
hex!("00000000000000000000004000000000"),
|
||
|
|
hex!("00000000000000000000008000000000"),
|
||
|
|
hex!("00000000000000000000000001000000"),
|
||
|
|
hex!("00000000000000000000000002000000"),
|
||
|
|
hex!("00000000000000000000000004000000"),
|
||
|
|
hex!("00000000000000000000000008000000"),
|
||
|
|
hex!("00000000000000000000000010000000"),
|
||
|
|
hex!("00000000000000000000000020000000"),
|
||
|
|
hex!("00000000000000000000000040000000"),
|
||
|
|
hex!("00000000000000000000000080000000"),
|
||
|
|
hex!("00000000000000000000000000010000"),
|
||
|
|
hex!("00000000000000000000000000020000"),
|
||
|
|
hex!("00000000000000000000000000040000"),
|
||
|
|
hex!("00000000000000000000000000080000"),
|
||
|
|
hex!("00000000000000000000000000100000"),
|
||
|
|
hex!("00000000000000000000000000200000"),
|
||
|
|
hex!("00000000000000000000000000400000"),
|
||
|
|
hex!("00000000000000000000000000800000"),
|
||
|
|
hex!("00000000000000000000000000000100"),
|
||
|
|
hex!("00000000000000000000000000000200"),
|
||
|
|
hex!("00000000000000000000000000000400"),
|
||
|
|
hex!("00000000000000000000000000000800"),
|
||
|
|
hex!("00000000000000000000000000001000"),
|
||
|
|
hex!("00000000000000000000000000002000"),
|
||
|
|
hex!("00000000000000000000000000004000"),
|
||
|
|
hex!("00000000000000000000000000008000"),
|
||
|
|
hex!("00000000000000000000000000000001"),
|
||
|
|
hex!("00000000000000000000000000000002"),
|
||
|
|
hex!("00000000000000000000000000000004"),
|
||
|
|
hex!("00000000000000000000000000000008"),
|
||
|
|
hex!("00000000000000000000000000000010"),
|
||
|
|
hex!("00000000000000000000000000000020"),
|
||
|
|
hex!("00000000000000000000000000000040"),
|
||
|
|
hex!("00000000000000000000000000000080"),
|
||
|
|
hex!("010000000000000000000000000000c2"),
|
||
|
|
];
|
||
|
|
}
|