Ecdh class abstract

ECDH with P-256 / P-384 / P-521 elliptic curve.

Private keys must be instances of EcKeyPair.

In browsers, the default implementation will use Web Cryptography API. On other platforms, DartEcdh will be used.

If you use Flutter, you can enable cryptography_flutter. It can improve performance in many cases.

Things to know

• Private keys are instances of EcKeyPair.
• Public keys are instances of EcPublicKey.
• You can use package:jwk to encode/decode JSON Web Key (JWK) data.

Example

import 'package:cryptography/cryptography.dart';

Future<void> main() async {
  final algorithm = Ecdh.p256();

  // We need the private key pair of Alice.
  final aliceKeyPair = await algorithm.newKeyPair();

  // We need only public key of Bob.
  final bobKeyPair = await algorithm.newKeyPair();
  final bobPublicKey = await bobKeyPair.extractPublicKey();

  // We can now calculate a 32-byte shared secret key.
  final sharedSecretKey = await algorithm.sharedSecretKey(
    keyPair: aliceKeyPair,
    remotePublicKey: bobPublicKey,
  );
}