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Implement Bleichenbacher PKCS padding oracle in Python

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This commit is contained in:
Felix Martin
2023-02-04 17:41:10 -05:00
parent edbe2144ae
commit fcb67889b9
4 changed files with 167 additions and 17 deletions
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16
src/main.rs
View File

@@ -62,15 +62,15 @@ fn main() {
set4::challenge30();
set4::challenge31();
set4::challenge32();
set5::challenge33();
set5::challenge34();
set5::challenge35();
set5::challenge36().unwrap_or_else(|| println!("[fail] challenge 36"));
set5::challenge37().unwrap_or_else(|| println!("[fail] challenge 37"));
set5::challenge38().unwrap_or_else(|| println!("[fail] challenge 38"));
set5::challenge39().unwrap_or_else(|| println!("[fail] challenge 39"));
set5::challenge40().unwrap_or_else(|| println!("[fail] challenge 40"));
}
set5::challenge33();
set5::challenge34();
set5::challenge35();
set5::challenge36().unwrap_or_else(|| println!("[fail] challenge 36"));
set5::challenge37().unwrap_or_else(|| println!("[fail] challenge 37"));
set5::challenge38().unwrap_or_else(|| println!("[fail] challenge 38"));
set5::challenge39().unwrap_or_else(|| println!("[fail] challenge 39"));
set5::challenge40().unwrap_or_else(|| println!("[fail] challenge 40"));
set6::challenge41().unwrap_or_else(|_| println!("[fail] challenge 41"));
set6::challenge42().unwrap_or_else(|_| println!("[fail] challenge 42"));
set6::challenge43().unwrap_or_else(|| println!("[fail] challenge 43"));

26
src/set6.rs
View File

@@ -410,12 +410,17 @@ pub fn challenge46() -> Result<(), ErrorStack> {
pub fn challenge47() -> Result<(), ErrorStack> {
// Generate a 256 bit keypair (that is, p and q will each be 128 bit primes), [n, e, d].
let (public_key, private_key) = rsa::rsa_gen_keys_with_size(128, 128)?;
println!("e={:?}", public_key.e);
println!("d={:?}", private_key.d);
println!("n={:?}", private_key.n);
// PKCS1.5-pad a short message, like "kick it, CC", and call it "m". Encrypt to to get "c".
let m = Bytes::from_utf8("kick it, CC");
let m = BigNum::from_slice(&m.0)?;
let n = bnclone(&public_key.n);
let n_bytes = n.num_bytes();
println!("m={:?}", m);
println!("n_bytes={}", n_bytes);
// Build an oracle function, just like you did in the last exercise, but have it check for
// plaintext[0] == 0 and plaintext[1] == 2.
@@ -428,15 +433,20 @@ pub fn challenge47() -> Result<(), ErrorStack> {
// Decrypt "c" using your padding oracle.
let c_unpadded = rsa::rsa_encrypt_unpadded(&m, &public_key)?;
let c = rsa::rsa_encrypt(&m, &public_key)?;
println!("c={:?}", c);
assert!(!oracle(&c_unpadded), "oracle wrongly thinks unpadded message is padded");
assert!(oracle(&c), "oracle wrongly thinks padded message is not padded");
// B = 2^(8(k−2)); k is the length of n in bytes;
// let mut ctx = BigNumContext::new()?;
// let mut p = BigNum::new()?;
// let k = BigNum::from_u32(n_bytes.try_into().unwrap())?;
// p.checked_sub(&k, &BigNum::from_u32(2)?);
// p = &p * BigNum::from_u32(8);
// b.exp(&BigNum::from_u32(2)?, &BigNum::from_u32(8)? * &(&n_bytes - &BigNum::from_u32(2)), &mut ctx);
assert!(
!oracle(&c_unpadded),
"oracle wrongly thinks unpadded message is padded"
);
assert!(
oracle(&c),
"oracle wrongly thinks padded message is not padded"
);
println!("[xxxx] Challenge 47: Bleichenbacher's PKCS 1.5 Padding Oracle (Simple Case)");
Ok(())