Finish Challenge 64 RSA parity oracle

src/rsa.rs

@@ -1,3 +1,4 @@
+use crate::utils::bnclone;
 use num_bigint::BigUint;
 use num_bigint::RandBigInt;
 use openssl::bn::BigNum;
@@ -62,8 +63,6 @@ pub fn rsa_gen_keys() -> Result<(RsaPublicKey, RsaPrivateKey), ErrorStack> {
         let mut n = BigNum::new()?;
         n.checked_mul(&p, &q, &mut ctx)?;
         // This is stupid but I couldn't figure out how to clone a bignum so we do this.
-        let mut n2 = BigNum::new()?;
-        n2.checked_mul(&p, &q, &mut ctx)?;
 
         // Let et be (p-1)*(q-1) (the "totient"). You need this value only for keygen.
         let mut et = BigNum::new()?;
@@ -80,7 +79,7 @@ pub fn rsa_gen_keys() -> Result<(RsaPublicKey, RsaPrivateKey), ErrorStack> {
         };
 
         // Your public key is [e, n]. Your private key is [d, n].
-        return Ok((RsaPublicKey { e, n }, RsaPrivateKey { d, n: n2 }));
+        return Ok((RsaPublicKey { e, n: bnclone(&n) }, RsaPrivateKey { d, n }));
     }
 }
 
@@ -120,12 +119,8 @@ pub fn invmod(a: &BigNum, n: &BigNum) -> Result<BigNum, ErrorStack> {
         Ok((r1, u1, v1))
     }
 
-    // No, couldn't think of a worse way to do that.
-    let a_cloned = BigNum::from_hex_str(&a.to_hex_str()?)?;
-    let n_cloned = BigNum::from_hex_str(&n.to_hex_str()?)?;
-
     // if v1 == 0 there is no mod_inverse
-    let (_, u1, _v1) = extended_gcd(a_cloned, n_cloned)?;
+    let (_, u1, _v1) = extended_gcd(bnclone(&a), bnclone(&n))?;
     let r_manual = &(&(&u1 % n) + n) % n;
 
     let mut ctx = BigNumContext::new()?;