use super::der;
use byteorder::{BigEndian, ByteOrder};
use num_bigint::BigUint;
use rand::Rng;
use sha1::{Digest, Sha1};
pub trait Padding {
fn pub_pad(&mut self, input: impl AsRef<[u8]>, k: usize) -> Vec<u8>;
}
#[derive(Debug)]
pub struct Pkcs1Padding<T> {
rng: T,
}
impl<T> Pkcs1Padding<T> {
pub fn new(rng: T) -> Self {
Self { rng }
}
}
impl<T: Rng> Padding for Pkcs1Padding<T> {
fn pub_pad(&mut self, input: impl AsRef<[u8]>, k: usize) -> Vec<u8> {
let input = input.as_ref();
let input_len = input.len();
assert!(
input_len < k - 11,
"The length of the data D shall not be more than k-11 octets"
);
let mut output = vec![0u8; k];
output[0] = 0x00;
output[1] = 0x02;
let ps_len = k - 3 - input_len;
for i in 0..ps_len {
let x = loop {
match self.rng.gen::<u8>() {
0x00 => continue,
x => break x,
}
};
output[i + 2] = x;
}
output[2 + ps_len] = 0x00;
output[2 + ps_len + 1..].copy_from_slice(input);
output
}
}
#[derive(Debug)]
pub struct Pkcs1OaepPadding<T> {
rng: T,
}
impl<T> Pkcs1OaepPadding<T> {
const HASH_LEN: usize = 20;
pub fn new(rng: T) -> Self {
Self { rng }
}
fn mgf1(seed: &[u8], len: usize) -> Vec<u8> {
if len as u64 > 2u64.pow(32) * Self::HASH_LEN as u64 {
panic!("mask too long");
}
fn ceil_div(dividend: usize, divisor: usize) -> usize {
let mut quotient = dividend / divisor;
if dividend % divisor > 0 {
quotient += 1;
}
quotient
}
let output = (0..ceil_div(len, Self::HASH_LEN))
.map(|c| {
let cs = &mut [0u8; 4];
BigEndian::write_u32(cs, c as u32);
Sha1::digest([seed, cs].concat()).to_vec()
})
.collect::<Vec<Vec<u8>>>()
.concat();
output[..len].into()
}
}
impl<T: Rng> Padding for Pkcs1OaepPadding<T> {
fn pub_pad(&mut self, input: impl AsRef<[u8]>, k: usize) -> Vec<u8> {
let input = input.as_ref();
if input.len() > k - 2 * Self::HASH_LEN - 1 {
panic!("message too long");
}
let mut ps = vec![0; k - input.len() - 2 * Self::HASH_LEN - 2];
ps.push(0x01);
let p_hash = Sha1::digest([]).to_vec();
let db = [&*p_hash, &*ps, input].concat();
let seed: Vec<_> = (0..Self::HASH_LEN).map(|_| self.rng.gen()).collect();
let db_mask = Self::mgf1(&seed, k - Self::HASH_LEN);
let masked_db: Vec<_> = db.into_iter().zip(db_mask).map(|(a, b)| a ^ b).collect();
let seed_mask = Self::mgf1(&masked_db, Self::HASH_LEN);
let masked_seed: Vec<_> = seed
.into_iter()
.zip(seed_mask)
.map(|(a, b)| a ^ b)
.collect();
[&*masked_seed, &*masked_db].concat()
}
}
#[derive(Debug)]
pub struct PublicKey {
modulus: BigUint,
exponent: BigUint,
}
impl PublicKey {
pub fn new(modulus: BigUint, exponent: BigUint) -> PublicKey {
PublicKey { modulus, exponent }
}
pub fn from_pem(pem_data: impl AsRef<[u8]>) -> PublicKey {
let (der, file_type) = der::pem_to_der(pem_data);
let (modulus, exponent) = der::parse_pub_key(&der, file_type);
PublicKey::new(modulus, exponent)
}
pub fn num_octets(&self) -> usize {
(self.modulus.bits() as usize + 6) >> 3
}
pub fn modulus(&self) -> &BigUint {
&self.modulus
}
pub fn exponent(&self) -> &BigUint {
&self.exponent
}
pub fn encrypt_block(&self, block: impl AsRef<[u8]>, mut pad: impl Padding) -> Vec<u8> {
let enc_block = pad.pub_pad(block, self.num_octets());
let enc_int = BigUint::from_bytes_be(&enc_block);
let rsa = enc_int.modpow(self.exponent(), self.modulus());
let mut rsa_bytes = rsa.to_bytes_be();
while rsa_bytes.len() < self.num_octets() {
rsa_bytes.insert(0, 0);
}
rsa_bytes
}
}
#[cfg(test)]
mod tests {
use std::io::Read;
use super::*;
use rand::RngCore;
const SEED: &[u8; 64] = b"\x03\x2e\x45\x32\x6f\xa8\x59\xa7\x2e\xc2\x35\xac\xff\x92\x9b\x15\xd1\
\x37\x2e\x30\xb2\x07\x25\x5f\x06\x11\xb8\xf7\x85\xd7\x64\x37\x41\x52\xe0\xac\x00\x9e\x50\x9e\
\x7b\xa3\x0c\xd2\xf1\x77\x8e\x11\x3b\x64\xe1\x35\xcf\x4e\x22\x92\xc7\x5e\xfe\x52\x88\xed\xfd\
\xa4";
const MASK: &[u8; 128] =
b"\x5f\x8d\xe1\x05\xb5\xe9\x6b\x2e\x49\x0d\xde\xcb\xd1\x47\xdd\x1d\xef\
\x7e\x3b\x8e\x0e\x6a\x26\xeb\x7b\x95\x6c\xcb\x8b\x3b\xdc\x1c\xa9\x75\xbc\x57\xc3\x98\x9e\x8f\
\xba\xd3\x1a\x22\x46\x55\xd8\x00\xc4\x69\x54\x84\x0f\xf3\x20\x52\xcd\xf0\xd6\x40\x56\x2b\xdf\
\xad\xfa\x26\x3c\xfc\xcf\x3c\x52\xb2\x9f\x2a\xf4\xa1\x86\x99\x59\xbc\x77\xf8\x54\xcf\x15\xbd\
\x7a\x25\x19\x29\x85\xa8\x42\xdb\xff\x8e\x13\xef\xee\x5b\x7e\x7e\x55\xbb\xe4\xd3\x89\x64\x7c\
\x68\x6a\x9a\x9a\xb3\xfb\x88\x9b\x2d\x77\x67\xd3\x83\x7e\xea\x4e\x0a\x2f\x04";
struct Seed<'a>(&'a [u8]);
impl<'a> RngCore for Seed<'a> {
fn next_u32(&mut self) -> u32 {
let mut buf = [0; 4];
self.fill_bytes(&mut buf);
u32::from_le_bytes(buf)
}
fn next_u64(&mut self) -> u64 {
let mut buf = [0; 8];
self.fill_bytes(&mut buf);
u64::from_le_bytes(buf)
}
fn fill_bytes(&mut self, dest: &mut [u8]) {
self.try_fill_bytes(dest).unwrap_or_else(|err| {
panic!(
"reading random bytes from Read implementation failed; error: {}",
err
)
});
}
fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), rand::Error> {
if dest.is_empty() {
return Ok(());
}
self.0.read_exact(dest).map_err(|e| rand::Error::new(e))
}
}
#[test]
fn mgf1() {
let mask = Pkcs1OaepPadding::<()>::mgf1(&SEED[..], 128);
assert_eq!(mask, &MASK[..]);
}
#[test]
fn rsa_pkcs() {
let modulus = vec![
0xa8, 0xb3, 0xb2, 0x84, 0xaf, 0x8e, 0xb5, 0x0b, 0x38, 0x70, 0x34, 0xa8, 0x60, 0xf1,
0x46, 0xc4, 0x91, 0x9f, 0x31, 0x87, 0x63, 0xcd, 0x6c, 0x55, 0x98, 0xc8, 0xae, 0x48,
0x11, 0xa1, 0xe0, 0xab, 0xc4, 0xc7, 0xe0, 0xb0, 0x82, 0xd6, 0x93, 0xa5, 0xe7, 0xfc,
0xed, 0x67, 0x5c, 0xf4, 0x66, 0x85, 0x12, 0x77, 0x2c, 0x0c, 0xbc, 0x64, 0xa7, 0x42,
0xc6, 0xc6, 0x30, 0xf5, 0x33, 0xc8, 0xcc, 0x72, 0xf6, 0x2a, 0xe8, 0x33, 0xc4, 0x0b,
0xf2, 0x58, 0x42, 0xe9, 0x84, 0xbb, 0x78, 0xbd, 0xbf, 0x97, 0xc0, 0x10, 0x7d, 0x55,
0xbd, 0xb6, 0x62, 0xf5, 0xc4, 0xe0, 0xfa, 0xb9, 0x84, 0x5c, 0xb5, 0x14, 0x8e, 0xf7,
0x39, 0x2d, 0xd3, 0xaa, 0xff, 0x93, 0xae, 0x1e, 0x6b, 0x66, 0x7b, 0xb3, 0xd4, 0x24,
0x76, 0x16, 0xd4, 0xf5, 0xba, 0x10, 0xd4, 0xcf, 0xd2, 0x26, 0xde, 0x88, 0xd3, 0x9f,
0x16, 0xfb,
];
let exponent = vec![0x01, 0x00, 0x01];
let msg1 = vec![
0x66, 0x28, 0x19, 0x4e, 0x12, 0x07, 0x3d, 0xb0, 0x3b, 0xa9, 0x4c, 0xda, 0x9e, 0xf9,
0x53, 0x23, 0x97, 0xd5, 0x0d, 0xba, 0x79, 0xb9, 0x87, 0x00, 0x4a, 0xfe, 0xfe, 0x34,
];
let seed1 = vec![
0x01, 0x00, 0x00, 0x00, 0x73, 0x00, 0x00, 0x00, 0x41, 0x00, 0x00, 0x00, 0xae, 0x00,
0x00, 0x00, 0x38, 0x00, 0x00, 0x00, 0x75, 0x00, 0x00, 0x00, 0xd5, 0x00, 0x00, 0x00,
0xf8, 0x00, 0x00, 0x00, 0x71, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0xf8, 0x00,
0x00, 0x00, 0xcc, 0x00, 0x00, 0x00, 0x4f, 0x00, 0x00, 0x00, 0xa9, 0x00, 0x00, 0x00,
0xb9, 0x00, 0x00, 0x00, 0xbc, 0x00, 0x00, 0x00, 0x15, 0x00, 0x00, 0x00, 0x6b, 0x00,
0x00, 0x00, 0xb0, 0x00, 0x00, 0x00, 0x46, 0x00, 0x00, 0x00, 0x28, 0x00, 0x00, 0x00,
0xfc, 0x00, 0x00, 0x00, 0xcd, 0x00, 0x00, 0x00, 0xb2, 0x00, 0x00, 0x00, 0xf4, 0x00,
0x00, 0x00, 0xf1, 0x00, 0x00, 0x00, 0x1e, 0x00, 0x00, 0x00, 0x90, 0x00, 0x00, 0x00,
0x5b, 0x00, 0x00, 0x00, 0xd3, 0x00, 0x00, 0x00, 0xa1, 0x00, 0x00, 0x00, 0x55, 0x00,
0x00, 0x00, 0xd3, 0x00, 0x00, 0x00, 0x76, 0x00, 0x00, 0x00, 0xf5, 0x00, 0x00, 0x00,
0x93, 0x00, 0x00, 0x00, 0xbd, 0x00, 0x00, 0x00, 0x73, 0x00, 0x00, 0x00, 0x04, 0x00,
0x00, 0x00, 0x21, 0x00, 0x00, 0x00, 0x08, 0x00, 0x00, 0x00, 0x74, 0x00, 0x00, 0x00,
0xeb, 0x00, 0x00, 0x00, 0xa0, 0x00, 0x00, 0x00, 0x8a, 0x00, 0x00, 0x00, 0x5e, 0x00,
0x00, 0x00, 0x22, 0x00, 0x00, 0x00, 0xbc, 0x00, 0x00, 0x00, 0xcc, 0x00, 0x00, 0x00,
0xb4, 0x00, 0x00, 0x00, 0xc9, 0x00, 0x00, 0x00, 0xd3, 0x00, 0x00, 0x00, 0x88, 0x00,
0x00, 0x00, 0x2a, 0x00, 0x00, 0x00, 0x93, 0x00, 0x00, 0x00, 0xa5, 0x00, 0x00, 0x00,
0x4d, 0x00, 0x00, 0x00, 0xb0, 0x00, 0x00, 0x00, 0x22, 0x00, 0x00, 0x00, 0xf5, 0x00,
0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0xd1, 0x00, 0x00, 0x00, 0x63, 0x00, 0x00, 0x00,
0x38, 0x00, 0x00, 0x00, 0xb6, 0x00, 0x00, 0x00, 0xb7, 0x00, 0x00, 0x00, 0xce, 0x00,
0x00, 0x00, 0x16, 0x00, 0x00, 0x00, 0xdc, 0x00, 0x00, 0x00, 0x7f, 0x00, 0x00, 0x00,
0x4b, 0x00, 0x00, 0x00, 0xbf, 0x00, 0x00, 0x00, 0x9a, 0x00, 0x00, 0x00, 0x96, 0x00,
0x00, 0x00, 0xb5, 0x00, 0x00, 0x00, 0x97, 0x00, 0x00, 0x00, 0x72, 0x00, 0x00, 0x00,
0xd6, 0x00, 0x00, 0x00, 0x60, 0x00, 0x00, 0x00, 0x6e, 0x00, 0x00, 0x00, 0x97, 0x00,
0x00, 0x00, 0x47, 0x00, 0x00, 0x00, 0xc7, 0x00, 0x00, 0x00, 0x64, 0x00, 0x00, 0x00,
0x9b, 0x00, 0x00, 0x00, 0xf9, 0x00, 0x00, 0x00, 0xe0, 0x00, 0x00, 0x00, 0x83, 0x00,
0x00, 0x00, 0xdb, 0x00, 0x00, 0x00, 0x98, 0x00, 0x00, 0x00, 0x18, 0x00, 0x00, 0x00,
0x84, 0x00, 0x00, 0x00, 0xa9, 0x00, 0x00, 0x00, 0x54, 0x00, 0x00, 0x00, 0xab, 0x00,
0x00, 0x00, 0x3c, 0x00, 0x00, 0x00, 0x6f, 0x00, 0x00, 0x00,
];
let cipher_text1 = vec![
0x50, 0xb4, 0xc1, 0x41, 0x36, 0xbd, 0x19, 0x8c, 0x2f, 0x3c, 0x3e, 0xd2, 0x43, 0xfc,
0xe0, 0x36, 0xe1, 0x68, 0xd5, 0x65, 0x17, 0x98, 0x4a, 0x26, 0x3c, 0xd6, 0x64, 0x92,
0xb8, 0x08, 0x04, 0xf1, 0x69, 0xd2, 0x10, 0xf2, 0xb9, 0xbd, 0xfb, 0x48, 0xb1, 0x2f,
0x9e, 0xa0, 0x50, 0x09, 0xc7, 0x7d, 0xa2, 0x57, 0xcc, 0x60, 0x0c, 0xce, 0xfe, 0x3a,
0x62, 0x83, 0x78, 0x9d, 0x8e, 0xa0, 0xe6, 0x07, 0xac, 0x58, 0xe2, 0x69, 0x0e, 0xc4,
0xeb, 0xc1, 0x01, 0x46, 0xe8, 0xcb, 0xaa, 0x5e, 0xd4, 0xd5, 0xcc, 0xe6, 0xfe, 0x7b,
0x0f, 0xf9, 0xef, 0xc1, 0xea, 0xbb, 0x56, 0x4d, 0xbf, 0x49, 0x82, 0x85, 0xf4, 0x49,
0xee, 0x61, 0xdd, 0x7b, 0x42, 0xee, 0x5b, 0x58, 0x92, 0xcb, 0x90, 0x60, 0x1f, 0x30,
0xcd, 0xa0, 0x7b, 0xf2, 0x64, 0x89, 0x31, 0x0b, 0xcd, 0x23, 0xb5, 0x28, 0xce, 0xab,
0x3c, 0x31,
];
let public_key = PublicKey::new(
BigUint::from_bytes_be(&modulus),
BigUint::from_bytes_be(&exponent),
);
let rng = Seed(&*seed1);
let pad = Pkcs1Padding::new(rng);
let cipher_text = public_key.encrypt_block(msg1, pad);
assert_eq!(cipher_text, cipher_text1);
}
#[test]
fn rsa_oaep() {
let modulus = vec![
0xbb, 0xf8, 0x2f, 0x09, 0x06, 0x82, 0xce, 0x9c, 0x23, 0x38, 0xac, 0x2b, 0x9d, 0xa8,
0x71, 0xf7, 0x36, 0x8d, 0x07, 0xee, 0xd4, 0x10, 0x43, 0xa4, 0x40, 0xd6, 0xb6, 0xf0,
0x74, 0x54, 0xf5, 0x1f, 0xb8, 0xdf, 0xba, 0xaf, 0x03, 0x5c, 0x02, 0xab, 0x61, 0xea,
0x48, 0xce, 0xeb, 0x6f, 0xcd, 0x48, 0x76, 0xed, 0x52, 0x0d, 0x60, 0xe1, 0xec, 0x46,
0x19, 0x71, 0x9d, 0x8a, 0x5b, 0x8b, 0x80, 0x7f, 0xaf, 0xb8, 0xe0, 0xa3, 0xdf, 0xc7,
0x37, 0x72, 0x3e, 0xe6, 0xb4, 0xb7, 0xd9, 0x3a, 0x25, 0x84, 0xee, 0x6a, 0x64, 0x9d,
0x06, 0x09, 0x53, 0x74, 0x88, 0x34, 0xb2, 0x45, 0x45, 0x98, 0x39, 0x4e, 0xe0, 0xaa,
0xb1, 0x2d, 0x7b, 0x61, 0xa5, 0x1f, 0x52, 0x7a, 0x9a, 0x41, 0xf6, 0xc1, 0x68, 0x7f,
0xe2, 0x53, 0x72, 0x98, 0xca, 0x2a, 0x8f, 0x59, 0x46, 0xf8, 0xe5, 0xfd, 0x09, 0x1d,
0xbd, 0xcb,
];
let exponent = vec![0x11];
let msg = vec![
0xd4, 0x36, 0xe9, 0x95, 0x69, 0xfd, 0x32, 0xa7, 0xc8, 0xa0, 0x5b, 0xbc, 0x90, 0xd3,
0x2c, 0x49,
];
let seed: Vec<u8> = vec![
0xaa, 0x00, 0x00, 0x00, 0xfd, 0x00, 0x00, 0x00, 0x12, 0x00, 0x00, 0x00, 0xf6, 0x00,
0x00, 0x00, 0x59, 0x00, 0x00, 0x00, 0xca, 0x00, 0x00, 0x00, 0xe6, 0x00, 0x00, 0x00,
0x34, 0x00, 0x00, 0x00, 0x89, 0x00, 0x00, 0x00, 0xb4, 0x00, 0x00, 0x00, 0x79, 0x00,
0x00, 0x00, 0xe5, 0x00, 0x00, 0x00, 0x07, 0x00, 0x00, 0x00, 0x6d, 0x00, 0x00, 0x00,
0xde, 0x00, 0x00, 0x00, 0xc2, 0x00, 0x00, 0x00, 0xf0, 0x00, 0x00, 0x00, 0x6c, 0x00,
0x00, 0x00, 0xb5, 0x00, 0x00, 0x00, 0x8f, 0x00, 0x00, 0x00,
];
let correct_cipher_text = vec![
0x12, 0x53, 0xe0, 0x4d, 0xc0, 0xa5, 0x39, 0x7b, 0xb4, 0x4a, 0x7a, 0xb8, 0x7e, 0x9b,
0xf2, 0xa0, 0x39, 0xa3, 0x3d, 0x1e, 0x99, 0x6f, 0xc8, 0x2a, 0x94, 0xcc, 0xd3, 0x00,
0x74, 0xc9, 0x5d, 0xf7, 0x63, 0x72, 0x20, 0x17, 0x06, 0x9e, 0x52, 0x68, 0xda, 0x5d,
0x1c, 0x0b, 0x4f, 0x87, 0x2c, 0xf6, 0x53, 0xc1, 0x1d, 0xf8, 0x23, 0x14, 0xa6, 0x79,
0x68, 0xdf, 0xea, 0xe2, 0x8d, 0xef, 0x04, 0xbb, 0x6d, 0x84, 0xb1, 0xc3, 0x1d, 0x65,
0x4a, 0x19, 0x70, 0xe5, 0x78, 0x3b, 0xd6, 0xeb, 0x96, 0xa0, 0x24, 0xc2, 0xca, 0x2f,
0x4a, 0x90, 0xfe, 0x9f, 0x2e, 0xf5, 0xc9, 0xc1, 0x40, 0xe5, 0xbb, 0x48, 0xda, 0x95,
0x36, 0xad, 0x87, 0x00, 0xc8, 0x4f, 0xc9, 0x13, 0x0a, 0xde, 0xa7, 0x4e, 0x55, 0x8d,
0x51, 0xa7, 0x4d, 0xdf, 0x85, 0xd8, 0xb5, 0x0d, 0xe9, 0x68, 0x38, 0xd6, 0x06, 0x3e,
0x09, 0x55,
];
let public_key = PublicKey::new(
BigUint::from_bytes_be(&modulus),
BigUint::from_bytes_be(&exponent),
);
let rng = Seed(&*seed);
let pad = Pkcs1OaepPadding::new(rng);
let cipher_text = public_key.encrypt_block(msg, pad);
assert_eq!(cipher_text, correct_cipher_text);
}
}