feat: add getCurves() to enumerate supported EC curves (#913)

Author: boorad

example/src/tests/ecdh/ecdh_tests.ts

@@ -1,5 +1,5 @@
 import { test } from '../util';
-import crypto, { Buffer } from 'react-native-quick-crypto';
+import crypto, { Buffer, getCurves } from 'react-native-quick-crypto';
 import { assert } from 'chai';
 
 const SUITE = 'ecdh';
@@ -68,3 +68,25 @@ test(SUITE, 'should work with string input', () => {
   const secret = alice.computeSecret(bobPubHex, 'hex');
   assert.isOk(secret);
 });
+
+test(SUITE, 'getCurves - should return array of supported curves', () => {
+  const curves = getCurves();
+  assert.isArray(curves);
+  assert.isAbove(curves.length, 0, 'should have at least one curve');
+
+  const expectedCurves = ['prime256v1', 'secp384r1', 'secp521r1', 'secp256k1'];
+  for (const curve of expectedCurves) {
+    assert.include(curves, curve, `should include ${curve}`);
+  }
+
+  const isSorted = curves.every(
+    (val: string, i: number) => i === 0 || val >= curves[i - 1]!,
+  );
+  assert.isTrue(isSorted, 'curves should be sorted alphabetically');
+});
+
+test(SUITE, 'getCurves - should match crypto.getCurves()', () => {
+  const named = getCurves();
+  const fromDefault = crypto.getCurves();
+  assert.deepEqual(named, fromDefault);
+});

packages/react-native-quick-crypto/cpp/ec/HybridEcKeyPair.cpp

@@ -1,5 +1,6 @@
 #include <NitroModules/ArrayBuffer.hpp>
 #include <NitroModules/Promise.hpp>
+#include <algorithm>
 #include <memory>
 #include <openssl/bio.h>
 #include <openssl/buffer.h>
@@ -425,4 +426,24 @@ void HybridEcKeyPair::checkKeyPair() {
   }
 }
 
+std::vector<std::string> HybridEcKeyPair::getSupportedCurves() {
+  const size_t count = EC_get_builtin_curves(nullptr, 0);
+  std::vector<EC_builtin_curve> curves(count);
+  if (EC_get_builtin_curves(curves.data(), count) != count) {
+    throw std::runtime_error("Failed to enumerate EC curves");
+  }
+
+  std::vector<std::string> names;
+  names.reserve(count);
+  for (const auto& curve : curves) {
+    const char* sn = OBJ_nid2sn(curve.nid);
+    if (sn != nullptr) {
+      names.emplace_back(sn);
+    }
+  }
+
+  std::sort(names.begin(), names.end());
+  return names;
+}
+
 } // namespace margelo::nitro::crypto

packages/react-native-quick-crypto/cpp/ec/HybridEcKeyPair.hpp

@@ -34,6 +34,7 @@ class HybridEcKeyPair : public HybridEcKeyPairSpec {
   std::shared_ptr<ArrayBuffer> sign(const std::shared_ptr<ArrayBuffer>& data, const std::string& hashAlgorithm) override;
   bool verify(const std::shared_ptr<ArrayBuffer>& data, const std::shared_ptr<ArrayBuffer>& signature,
               const std::string& hashAlgorithm) override;
+  std::vector<std::string> getSupportedCurves() override;
 
  protected:
   void checkKeyPair();

packages/react-native-quick-crypto/nitrogen/generated/shared/c++/HybridEcKeyPairSpec.cpp

@@ -34,6 +34,23 @@ import {
 import { Buffer } from '@craftzdog/react-native-buffer';
 import { ECDH } from './ecdh';
 
+class EcUtils {
+  private static _native: EcKeyPair | undefined;
+  private static get native(): EcKeyPair {
+    if (!this._native) {
+      this._native = NitroModules.createHybridObject<EcKeyPair>('EcKeyPair');
+    }
+    return this._native;
+  }
+  public static getSupportedCurves(): string[] {
+    return this.native.getSupportedCurves();
+  }
+}
+
+export function getCurves(): string[] {
+  return EcUtils.getSupportedCurves();
+}
+
 export class Ec {
   native: EcKeyPair;
 

packages/react-native-quick-crypto/nitrogen/generated/shared/c++/HybridEcKeyPairSpec.hpp

@@ -14,6 +14,7 @@ import * as scrypt from './scrypt';
 import * as random from './random';
 import * as ecdh from './ecdh';
 import * as dh from './diffie-hellman';
+import { getCurves } from './ec';
 import { constants } from './constants';
 
 // utils import
@@ -39,6 +40,7 @@ const QuickCrypto = {
   ...dh,
   ...utils,
   ...subtle,
+  getCurves,
   constants,
   Buffer,
 };
@@ -81,6 +83,7 @@ export * from './pbkdf2';
 export * from './scrypt';
 export * from './random';
 export * from './ecdh';
+export { getCurves } from './ec';
 export * from './diffie-hellman';
 export * from './utils';
 export * from './subtle';

packages/react-native-quick-crypto/src/ec.ts

@@ -35,4 +35,6 @@ export interface EcKeyPair
     signature: ArrayBuffer,
     hashAlgorithm: string,
   ): boolean;
+
+  getSupportedCurves(): string[];
 }