with all security checks in place, the code is now accepting protocol_tx outputs as valid in-wallet; only the asset_type is misreported now

src/crypto/crypto.cpp

@@ -261,6 +261,67 @@ namespace crypto {
     return true;
   }
 
+  /**
+   * The following functions are designed to perform the correct encoding / decoding for protocol_tx outputs,
+   * which use a hash of a crypto::key_image for uniqueness
+   */
+  void crypto_ops::derivation_to_scalar(const key_derivation &derivation, const hash& uniqueness, ec_scalar &res) {
+    struct {
+      hash uniqueness;
+      key_derivation derivation;
+    } buf;
+    buf.uniqueness = uniqueness;
+    buf.derivation = derivation;
+    hash_to_scalar(&buf, sizeof(buf), res);
+  }
+
+  bool crypto_ops::derive_public_key(const key_derivation &derivation, const hash& uniqueness,
+    const public_key &base, public_key &derived_key) {
+    ec_scalar scalar;
+    ge_p3 point1;
+    ge_p3 point2;
+    ge_cached point3;
+    ge_p1p1 point4;
+    ge_p2 point5;
+    if (ge_frombytes_vartime(&point1, &base) != 0) {
+      return false;
+    }
+    derivation_to_scalar(derivation, uniqueness, scalar);
+    ge_scalarmult_base(&point2, &scalar);
+    ge_p3_to_cached(&point3, &point2);
+    ge_add(&point4, &point1, &point3);
+    ge_p1p1_to_p2(&point5, &point4);
+    ge_tobytes(&derived_key, &point5);
+    return true;
+  }
+
+  void crypto_ops::derive_secret_key(const key_derivation &derivation, const hash& uniqueness,
+    const secret_key &base, secret_key &derived_key) {
+    ec_scalar scalar;
+    assert(sc_check(&base) == 0);
+    derivation_to_scalar(derivation, uniqueness, scalar);
+    sc_add(&unwrap(derived_key), &unwrap(base), &scalar);
+  }
+
+  bool crypto_ops::derive_subaddress_public_key(const public_key &out_key, const key_derivation &derivation, const hash& uniqueness, public_key &derived_key) {
+    ec_scalar scalar;
+    ge_p3 point1;
+    ge_p3 point2;
+    ge_cached point3;
+    ge_p1p1 point4;
+    ge_p2 point5;
+    if (ge_frombytes_vartime(&point1, &out_key) != 0) {
+      return false;
+    }
+    derivation_to_scalar(derivation, uniqueness, scalar);
+    ge_scalarmult_base(&point2, &scalar);
+    ge_p3_to_cached(&point3, &point2);
+    ge_sub(&point4, &point1, &point3);
+    ge_p1p1_to_p2(&point5, &point4);
+    ge_tobytes(&derived_key, &point5);
+    return true;
+  }
+
   struct s_comm {
     hash h;
     ec_point key;