Fix RSA bug that I did not generate random primes for p and q

src/set6.rs

@@ -16,7 +16,8 @@ pub fn challenge41() -> Option<()> {
     public_key.n.rand_range(&mut s).ok()?;
     // C' = ((S**E mod N) C) mod N
     let mut c2 = BigNum::new().ok()?;
-    c2.mod_exp(&s, &public_key.e, &public_key.n, &mut ctx).ok()?;
+    c2.mod_exp(&s, &public_key.e, &public_key.n, &mut ctx)
+        .ok()?;
     let c2 = &(&c2 * &c) % &public_key.n;
     let p2 = rsa::rsa_decrypt(&c2, &private_key).ok()?;
 
@@ -29,3 +30,15 @@ pub fn challenge41() -> Option<()> {
     println!("[okay] Challenge 41: implement unpadded message recovery oracle");
     Some(())
 }
+
+pub fn challenge42() -> Option<()> {
+    let (public_key, private_key) = rsa::rsa_gen_keys().ok()?;
+
+    let i = BigNum::from_u32(1337).ok()?;
+    let c = rsa::rsa_encrypt(&i, &public_key).ok()?;
+    let m = rsa::rsa_decrypt(&c, &private_key).ok()?;
+    assert_eq!(i, m, "rsa is broken");
+
+    println!("[xxxx] Challenge 42: Bleichenbacher's e=3 RSA Attack");
+    None
+}