LibWeb: Implement ED25519 generateKey for SubtleCrypto

Author: https://github.com/stelar7
Commit: ec015034bd
Pull-request: https://github.com/SerenityOS/serenity/pull/23737
Reviewed-by: https://github.com/ADKaster ✅
Reviewed-by: https://github.com/trflynn89

Userland/Libraries/LibWeb/Crypto/CryptoAlgorithms.cpp

@@ -7,6 +7,7 @@
 #include <AK/Base64.h>
 #include <AK/QuickSort.h>
 #include <LibCrypto/ASN1/DER.h>
+#include <LibCrypto/Curves/Ed25519.h>
 #include <LibCrypto/Curves/SECPxxxr1.h>
 #include <LibCrypto/Hash/HashManager.h>
 #include <LibCrypto/PK/RSA.h>
@@ -1210,4 +1211,71 @@ WebIDL::ExceptionOr<JS::Value> ECDSA::verify(AlgorithmParams const& params, JS::
     return JS::Value(result);
 }
 
+// https://wicg.github.io/webcrypto-secure-curves/#ed25519-operations
+WebIDL::ExceptionOr<Variant<JS::NonnullGCPtr<CryptoKey>, JS::NonnullGCPtr<CryptoKeyPair>>> ED25519::generate_key([[maybe_unused]] AlgorithmParams const& params, bool extractable, Vector<Bindings::KeyUsage> const& key_usages)
+{
+    // 1. If usages contains a value which is not one of "sign" or "verify", then throw a SyntaxError.
+    for (auto const& usage : key_usages) {
+        if (usage != Bindings::KeyUsage::Sign && usage != Bindings::KeyUsage::Verify) {
+            return WebIDL::SyntaxError::create(m_realm, MUST(String::formatted("Invalid key usage '{}'", idl_enum_to_string(usage))));
+        }
+    }
+
+    // 2. Generate an Ed25519 key pair, as defined in [RFC8032], section 5.1.5.
+    ::Crypto::Curves::Ed25519 curve;
+    auto maybe_private_key = curve.generate_private_key();
+    if (maybe_private_key.is_error())
+        return WebIDL::OperationError::create(m_realm, "Failed to generate private key"_fly_string);
+    auto private_key_data = maybe_private_key.release_value();
+
+    auto maybe_public_key = curve.generate_public_key(private_key_data);
+    if (maybe_public_key.is_error())
+        return WebIDL::OperationError::create(m_realm, "Failed to generate public key"_fly_string);
+    auto public_key_data = maybe_public_key.release_value();
+
+    // 3. Let algorithm be a new KeyAlgorithm object.
+    auto algorithm = KeyAlgorithm::create(m_realm);
+
+    // 4. Set the name attribute of algorithm to "Ed25519".
+    algorithm->set_name("Ed25519"_string);
+
+    // 5. Let publicKey be a new CryptoKey associated with the relevant global object of this [HTML],
+    // and representing the public key of the generated key pair.
+    auto public_key = CryptoKey::create(m_realm, CryptoKey::InternalKeyData { public_key_data });
+
+    // 6. Set the [[type]] internal slot of publicKey to "public"
+    public_key->set_type(Bindings::KeyType::Public);
+
+    // 7. Set the [[algorithm]] internal slot of publicKey to algorithm.
+    public_key->set_algorithm(algorithm);
+
+    // 8. Set the [[extractable]] internal slot of publicKey to true.
+    public_key->set_extractable(true);
+
+    // 9. Set the [[usages]] internal slot of publicKey to be the usage intersection of usages and [ "verify" ].
+    public_key->set_usages(usage_intersection(key_usages, { { Bindings::KeyUsage::Verify } }));
+
+    // 10. Let privateKey be a new CryptoKey associated with the relevant global object of this [HTML],
+    // and representing the private key of the generated key pair.
+    auto private_key = CryptoKey::create(m_realm, CryptoKey::InternalKeyData { private_key_data });
+
+    // 11. Set the [[type]] internal slot of privateKey to "private"
+    private_key->set_type(Bindings::KeyType::Private);
+
+    // 12. Set the [[algorithm]] internal slot of privateKey to algorithm.
+    private_key->set_algorithm(algorithm);
+
+    // 13. Set the [[extractable]] internal slot of privateKey to extractable.
+    private_key->set_extractable(extractable);
+
+    // 14. Set the [[usages]] internal slot of privateKey to be the usage intersection of usages and [ "sign" ].
+    private_key->set_usages(usage_intersection(key_usages, { { Bindings::KeyUsage::Sign } }));
+
+    // 15. Let result be a new CryptoKeyPair dictionary.
+    // 16. Set the publicKey attribute of result to be publicKey.
+    // 17. Set the privateKey attribute of result to be privateKey.
+    // 18. Return the result of converting result to an ECMAScript Object, as defined by [WebIDL].
+    return Variant<JS::NonnullGCPtr<CryptoKey>, JS::NonnullGCPtr<CryptoKeyPair>> { CryptoKeyPair::create(m_realm, public_key, private_key) };
+}
+
 }