Implement working unpack for bink1998

src/key.rs

@@ -0,0 +1,46 @@
+use std::collections::VecDeque;
+
+use openssl::bn::BigNum;
+
+const P_CHARSET: [char; 24] = [
+    'B', 'C', 'D', 'F', 'G', 'H', 'J', 'K', 'M', 'P', 'Q', 'R', 'T', 'V', 'W', 'X', 'Y', '2', '3',
+    '4', '6', '7', '8', '9',
+];
+
+const PK_LENGTH: usize = 25;
+
+pub fn unbase24(cd_key: &str) -> Vec<u8> {
+    let p_decoded_key: Vec<u8> = cd_key
+        .chars()
+        .filter_map(|c| P_CHARSET.iter().position(|&x| x == c).map(|i| i as u8))
+        .collect();
+
+    let mut y = BigNum::from_u32(0).unwrap();
+
+    for i in p_decoded_key {
+        y.mul_word((PK_LENGTH - 1) as u32).unwrap();
+        y.add_word(i.into()).unwrap();
+    }
+
+    y.to_vec()
+}
+
+pub fn base24(byte_seq: &[u8]) -> String {
+    let mut z = BigNum::from_slice(byte_seq).unwrap();
+    let mut out: VecDeque<char> = VecDeque::new();
+    (0..=24).for_each(|_| out.push_front(P_CHARSET[z.div_word(24).unwrap() as usize]));
+    out.iter().collect()
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_base24() {
+        let input = "JTW3TJ7PFJ7V9CCMX84V9PFT8";
+        let unbase24 = super::unbase24(input);
+        println!("{:?}", unbase24);
+        let base24 = super::base24(&unbase24);
+        println!("{}", base24);
+        assert_eq!(input, base24);
+    }
+}