umskt-rs/src/bink1998.rs
2023-06-20 22:35:15 -04:00

242 lines
6.9 KiB
Rust

use anyhow::Result;
use bitreader::BitReader;
use openssl::{
bn::{BigNum, BigNumContext, MsbOption},
ec::{EcGroup, EcPoint},
sha::sha1,
};
use crate::key::{base24_decode, base24_encode};
const FIELD_BITS: i32 = 384;
const FIELD_BYTES: usize = 48;
const SHA_MSG_LENGTH: usize = 4 + 2 * FIELD_BYTES;
#[derive(Clone, Copy, Debug)]
struct ProductKey {
upgrade: bool,
serial: u32,
hash: u32,
signature: u64,
}
pub fn verify(
e_curve: &EcGroup,
base_point: &EcPoint,
public_key: &EcPoint,
p_key: &str,
) -> Result<bool> {
let mut num_context = BigNumContext::new()?;
let p_raw = base24_decode(p_key);
let product_key = unpack(&p_raw)?;
let p_data = product_key.serial << 1 | product_key.upgrade as u32;
let e = BigNum::from_u32(product_key.hash)?;
let s = BigNum::from_slice(&product_key.signature.to_be_bytes())?;
let mut x = BigNum::new()?;
let mut y = BigNum::new()?;
let mut t = EcPoint::new(e_curve)?;
let mut p = EcPoint::new(e_curve)?;
let mut p_2 = EcPoint::new(e_curve)?;
t.mul(e_curve, base_point, &s, &num_context)?;
p.mul(e_curve, public_key, &e, &num_context)?;
p_2.mul(e_curve, public_key, &e, &num_context)?;
p.add(e_curve, &t, &p_2, &mut num_context)?;
p.affine_coordinates(e_curve, &mut x, &mut y, &mut num_context)?;
let mut msg_buffer: [u8; SHA_MSG_LENGTH] = [0; SHA_MSG_LENGTH];
let mut x_bin = x.to_vec_padded(FIELD_BYTES as i32)?;
x_bin.reverse();
let mut y_bin = y.to_vec_padded(FIELD_BYTES as i32)?;
y_bin.reverse();
msg_buffer[0..4].copy_from_slice(&p_data.to_le_bytes());
msg_buffer[4..4 + FIELD_BYTES].copy_from_slice(&x_bin);
msg_buffer[4 + FIELD_BYTES..4 + FIELD_BYTES * 2].copy_from_slice(&y_bin);
let msg_digest = sha1(&msg_buffer);
let hash: u32 =
u32::from_le_bytes(msg_digest[0..4].try_into().unwrap()) >> 4 & bitmask(28) as u32;
Ok(hash == product_key.hash)
}
pub fn generate(
e_curve: &EcGroup,
base_point: &EcPoint,
gen_order: &BigNum,
private_key: &BigNum,
p_serial: u32,
p_upgrade: bool,
) -> Result<String> {
let mut num_context = BigNumContext::new().unwrap();
let mut c = BigNum::new()?;
let mut s = BigNum::new()?;
let mut s_2 = BigNum::new()?;
let mut x = BigNum::new()?;
let mut y = BigNum::new()?;
let p_data = p_serial << 1 | p_upgrade as u32;
let p_raw = loop {
let mut r = EcPoint::new(e_curve)?;
// Generate a random number c consisting of 384 bits without any constraints.
c.rand(FIELD_BITS, MsbOption::MAYBE_ZERO, false)?;
// Pick a random derivative of the base point on the elliptic curve.
// R = cG;
r.mul(e_curve, base_point, &c, &num_context)?;
// Acquire its coordinates.
// x = R.x; y = R.y;
r.affine_coordinates(e_curve, &mut x, &mut y, &mut num_context)?;
let mut msg_buffer: [u8; SHA_MSG_LENGTH] = [0; SHA_MSG_LENGTH];
let mut x_bin = x.to_vec_padded(FIELD_BYTES as i32)?;
x_bin.reverse();
let mut y_bin = y.to_vec_padded(FIELD_BYTES as i32)?;
y_bin.reverse();
msg_buffer[0..4].copy_from_slice(&p_data.to_le_bytes());
msg_buffer[4..4 + FIELD_BYTES].copy_from_slice(&x_bin);
msg_buffer[4 + FIELD_BYTES..4 + FIELD_BYTES * 2].copy_from_slice(&y_bin);
let msg_digest = sha1(&msg_buffer);
let p_hash: u32 =
u32::from_le_bytes(msg_digest[0..4].try_into().unwrap()) >> 4 & bitmask(28) as u32;
s_2.copy_from_slice(&private_key.to_vec())?;
s_2.mul_word(p_hash)?;
s.mod_add(&s_2, &c, gen_order, &mut num_context)?;
let p_signature = u64::from_be_bytes(s.to_vec_padded(8)?.try_into().unwrap());
if p_signature <= bitmask(55) {
break pack(ProductKey {
upgrade: p_upgrade,
serial: p_serial,
hash: p_hash,
signature: p_signature,
});
}
};
Ok(base24_encode(&p_raw))
}
const HASH_LENGTH_BITS: u8 = 28;
const SERIAL_LENGTH_BITS: u8 = 30;
const UPGRADE_LENGTH_BITS: u8 = 1;
const EVERYTHING_ELSE: u8 = HASH_LENGTH_BITS + SERIAL_LENGTH_BITS + UPGRADE_LENGTH_BITS;
fn unpack(p_raw: &[u8]) -> Result<ProductKey> {
let mut reader = BitReader::new(p_raw);
// The signature length is unknown, but everything else is, so we can calculate it
let signature_length_bits = (p_raw.len() * 8) as u8 - EVERYTHING_ELSE;
let p_signature = reader.read_u64(signature_length_bits)?;
let p_hash = reader.read_u32(HASH_LENGTH_BITS)?;
let p_serial = reader.read_u32(SERIAL_LENGTH_BITS)?;
let p_upgrade = reader.read_bool()?;
Ok(ProductKey {
upgrade: p_upgrade,
serial: p_serial,
hash: p_hash,
signature: p_signature,
})
}
fn pack(p_key: ProductKey) -> Vec<u8> {
let mut p_raw: u128 = 0;
p_raw |= (p_key.signature as u128) << EVERYTHING_ELSE;
p_raw |= (p_key.hash as u128) << (SERIAL_LENGTH_BITS + UPGRADE_LENGTH_BITS);
p_raw |= (p_key.serial as u128) << UPGRADE_LENGTH_BITS;
p_raw |= p_key.upgrade as u128;
p_raw
.to_be_bytes()
.into_iter()
.skip_while(|&x| x == 0)
.collect()
}
fn bitmask(n: u64) -> u64 {
(1 << n) - 1
}
#[cfg(test)]
mod tests {
use std::{fs::File, io::BufReader};
use serde_json::from_reader;
use crate::crypto::initialize_elliptic_curve;
#[test]
fn verify_test() {
// Example product key and its BINK ID
let product_key = "D9924-R6BG2-39J83-RYKHF-W47TT";
let bink_id = "2E";
// Load keys.json
let path = "keys.json";
let file = File::open(path).unwrap();
let reader = BufReader::new(file);
let keys: serde_json::Value = from_reader(reader).unwrap();
let bink = &keys["BINK"][&bink_id];
let p = bink["p"].as_str().unwrap();
let a = bink["a"].as_str().unwrap();
let b = bink["b"].as_str().unwrap();
let gx = bink["g"]["x"].as_str().unwrap();
let gy = bink["g"]["y"].as_str().unwrap();
let kx = bink["pub"]["x"].as_str().unwrap();
let ky = bink["pub"]["y"].as_str().unwrap();
let (e_curve, gen_point, pub_point) = initialize_elliptic_curve(p, a, b, gx, gy, kx, ky);
assert!(super::verify(&e_curve, &gen_point, &pub_point, product_key).unwrap());
assert!(!super::verify(
&e_curve,
&gen_point,
&pub_point,
"11111-R6BG2-39J83-RYKHF-W47TT"
)
.unwrap());
}
#[test]
fn pack_test() {
let p_key = super::ProductKey {
upgrade: false,
serial: 640010550,
hash: 39185432,
signature: 6939952665262054,
};
let p_raw = super::pack(p_key);
assert_eq!(
p_raw,
vec![
0xC5, 0x3E, 0xCD, 0x2A, 0xF7, 0xBF, 0x31, 0x2A, 0xF6, 0x0C, 0x4C, 0x4B, 0x92, 0x6C
]
);
}
}