Axone
Axone
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DDeno
Created by Axone on 8/5/2023 in #help
Bad implementation of X25519?
So in the javascript, you should just check if the value is true, correct me if I'm wrong
7 replies
DDeno
Created by Axone on 8/5/2023 in #help
Bad implementation of X25519?
And it seems that the function does not return if it is the identity point, but if the generated secret successfully passes the test
7 replies
DDeno
Created by Axone on 8/5/2023 in #help
Bad implementation of X25519?
And I try to read some rust (https://github.com/denoland/deno/blob/main/ext/crypto/x25519.rs#L35) 
#[op(fast)]
pub fn op_crypto_derive_bits_x25519(
  k: &[u8],
  u: &[u8],
  secret: &mut [u8],
) -> bool {
  let k: [u8; 32] = k.try_into().expect("Expected byteLength 32");
  let u: [u8; 32] = u.try_into().expect("Expected byteLength 32");
  let sh_sec = x25519_dalek::x25519(k, u);
  let point = MontgomeryPoint(sh_sec);
  if point.ct_eq(&MONTGOMERY_IDENTITY).unwrap_u8() == 1 {
    return false;
  }
  secret.copy_from_slice(&sh_sec);
  true
}
#[op(fast)]
pub fn op_crypto_derive_bits_x25519(
  k: &[u8],
  u: &[u8],
  secret: &mut [u8],
) -> bool {
  let k: [u8; 32] = k.try_into().expect("Expected byteLength 32");
  let u: [u8; 32] = u.try_into().expect("Expected byteLength 32");
  let sh_sec = x25519_dalek::x25519(k, u);
  let point = MontgomeryPoint(sh_sec);
  if point.ct_eq(&MONTGOMERY_IDENTITY).unwrap_u8() == 1 {
    return false;
  }
  secret.copy_from_slice(&sh_sec);
  true
}
7 replies
DDeno
Created by Axone on 8/5/2023 in #help
Bad implementation of X25519?
After some research (https://vnhacker.blogspot.com/2015/09/why-not-validating-curve25519-public.html) I found what the isIdentity test was for
7 replies
DDeno
Created by Axone on 8/5/2023 in #help
Bad implementation of X25519?
If we look at the implementation we can see the following code: (https://github.com/denoland/deno/blob/8ae706293149fb6e3d40af3ac80a8661fa379111/ext/crypto/00_crypto.js#L4346) 
case "X25519": {
      // 1.
      if (baseKey[_type] !== "private") {
        throw new DOMException("Invalid key type", "InvalidAccessError");
      }
      // 2.
      const publicKey = normalizedAlgorithm.public;
      // 3.
      if (publicKey[_type] !== "public") {
        throw new DOMException("Invalid key type", "InvalidAccessError");
      }
      // 4.
      if (publicKey[_algorithm].name !== baseKey[_algorithm].name) {
        throw new DOMException(
          "Algorithm mismatch",
          "InvalidAccessError",
        );
      }

      // 5.
      const kHandle = baseKey[_handle];
      const k = WeakMapPrototypeGet(KEY_STORE, kHandle);

      const uHandle = publicKey[_handle];
      const u = WeakMapPrototypeGet(KEY_STORE, uHandle);

      const secret = new Uint8Array(32);
      const isIdentity = ops.op_crypto_derive_bits_x25519(k, u, secret);

      // 6.
      if (isIdentity) {
        throw new DOMException("Invalid key", "OperationError");
      }
case "X25519": {
      // 1.
      if (baseKey[_type] !== "private") {
        throw new DOMException("Invalid key type", "InvalidAccessError");
      }
      // 2.
      const publicKey = normalizedAlgorithm.public;
      // 3.
      if (publicKey[_type] !== "public") {
        throw new DOMException("Invalid key type", "InvalidAccessError");
      }
      // 4.
      if (publicKey[_algorithm].name !== baseKey[_algorithm].name) {
        throw new DOMException(
          "Algorithm mismatch",
          "InvalidAccessError",
        );
      }

      // 5.
      const kHandle = baseKey[_handle];
      const k = WeakMapPrototypeGet(KEY_STORE, kHandle);

      const uHandle = publicKey[_handle];
      const u = WeakMapPrototypeGet(KEY_STORE, uHandle);

      const secret = new Uint8Array(32);
      const isIdentity = ops.op_crypto_derive_bits_x25519(k, u, secret);

      // 6.
      if (isIdentity) {
        throw new DOMException("Invalid key", "OperationError");
      }
7 replies
DDeno
Created by Axone on 8/5/2023 in #help
Bad implementation of X25519?
error: Uncaught OperationError: Invalid key
const secret = await crypto.subtle.deriveBits(
                                   ^
    at deriveBits (ext:deno_crypto/00_crypto.js:4483:15)
    at SubtleCrypto.deriveBits (ext:deno_crypto/00_crypto.js:1123:26)
    at file:///D:/Codes/deno/axon/x25519.ts:11:36
error: Uncaught OperationError: Invalid key
const secret = await crypto.subtle.deriveBits(
                                   ^
    at deriveBits (ext:deno_crypto/00_crypto.js:4483:15)
    at SubtleCrypto.deriveBits (ext:deno_crypto/00_crypto.js:1123:26)
    at file:///D:/Codes/deno/axon/x25519.ts:11:36
7 replies