pub struct Md5 {
state: [u32; 4],
buf: [u8; 64],
buf_len: usize,
len: u64,
}
const S: [u32; 64] = [
7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 6, 10, 15, 21, 6,
10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21,
];
const K: [u32; 64] = [
0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501, 0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be, 0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,
0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa, 0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8, 0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed, 0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,
0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c, 0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70, 0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05, 0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1, 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1, 0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391,
];
impl Default for Md5 {
fn default() -> Self {
Self::new()
}
}
impl Md5 {
pub fn new() -> Self {
Md5 {
state: [0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476],
buf: [0; 64],
buf_len: 0,
len: 0,
}
}
fn block(state: &mut [u32; 4], block: &[u8]) {
let mut m = [0u32; 16];
for (i, w) in m.iter_mut().enumerate() {
*w = u32::from_le_bytes([block[i * 4], block[i * 4 + 1], block[i * 4 + 2], block[i * 4 + 3]]);
}
let (mut a, mut b, mut c, mut d) = (state[0], state[1], state[2], state[3]);
for i in 0..64 {
let (f, g) = match i / 16 {
0 => ((b & c) | (!b & d), i),
1 => ((d & b) | (!d & c), (5 * i + 1) % 16),
2 => (b ^ c ^ d, (3 * i + 5) % 16),
_ => (c ^ (b | !d), (7 * i) % 16),
};
let f = f.wrapping_add(a).wrapping_add(K[i]).wrapping_add(m[g]);
a = d;
d = c;
c = b;
b = b.wrapping_add(f.rotate_left(S[i]));
}
state[0] = state[0].wrapping_add(a);
state[1] = state[1].wrapping_add(b);
state[2] = state[2].wrapping_add(c);
state[3] = state[3].wrapping_add(d);
}
pub fn update(&mut self, mut data: &[u8]) {
self.len += data.len() as u64;
if self.buf_len > 0 {
let take = (64 - self.buf_len).min(data.len());
self.buf[self.buf_len..self.buf_len + take].copy_from_slice(&data[..take]);
self.buf_len += take;
data = &data[take..];
if self.buf_len == 64 {
let b = self.buf;
Self::block(&mut self.state, &b);
self.buf_len = 0;
}
}
while data.len() >= 64 {
Self::block(&mut self.state, &data[..64]);
data = &data[64..];
}
if !data.is_empty() {
self.buf[..data.len()].copy_from_slice(data);
self.buf_len = data.len();
}
}
pub fn finalize(mut self) -> [u8; 16] {
let bits = self.len.wrapping_mul(8);
self.update(&[0x80]);
while self.buf_len != 56 {
self.update(&[0]);
}
self.update(&bits.to_le_bytes());
let mut out = [0u8; 16];
for i in 0..4 {
out[i * 4..i * 4 + 4].copy_from_slice(&self.state[i].to_le_bytes());
}
out
}
}
#[cfg(test)]
mod tests {
use super::*;
fn hex(d: [u8; 16]) -> String {
d.iter().map(|b| format!("{b:02x}")).collect()
}
#[test]
fn rfc_vectors() {
let mut m = Md5::new();
m.update(b"");
assert_eq!(hex(m.finalize()), "d41d8cd98f00b204e9800998ecf8427e");
let mut m = Md5::new();
m.update(b"abc");
assert_eq!(hex(m.finalize()), "900150983cd24fb0d6963f7d28e17f72");
let mut m = Md5::new();
m.update(b"12345678901234567890123456789012345678901234567890123456789012345678901234567890");
assert_eq!(hex(m.finalize()), "57edf4a22be3c955ac49da2e2107b67a");
let mut m = Md5::new();
m.update(b"1234567890123456789012345678901234567890");
m.update(b"1234567890123456789012345678901234567890");
assert_eq!(hex(m.finalize()), "57edf4a22be3c955ac49da2e2107b67a");
}
}