ECDH

W3 specification

Operations

Operation	Parameters	Result
generateKey	EcKeyGenParams	CryptoKeyPair
importKey	EcKeyImportParams	CryptoKey
exportKey	None	JsonWebKey or BufferSource
deriveBits	EcdhKeyDeriveParams	ArrayBuffer
deriveKey	EcdhKeyDeriveParams	CryptoKey

Generate key

const keys = await crypto.subtle.generateKey(
  {
    name: "ECDH",
    namedCurve: "P-256", // P-256, P-384, or P-521
  },
  false,
  ["deriveKey", "deriveBits"],
);

Import key

const publicKey = await crypto.subtle.importKey(
  "jwk",
  {
    crv: "P-521",
    ext: true,
    key_ops: [],
    kty: "EC",
    x: "Adqn62IVQX8LIauAXrUtxH05DHlRygKcsP9qWAnd9tfJvpaG7bzIs16WMEUe1V-f4AxbQJceU4xCP8dJppK_fzdC",
    y: "AEo3s1eExCOvpuBtBWnWlr7TuFhq_fMzqX9eqDHiy8qWl4I_koQtMePodrAc85mVrJAjvsa77Y3Ul3QtIWpXXBqa",
  },
  {
    name: "ECDH",
    namedCurve: "P-521",
  },
  false,
  [],
);

Export key

const jwk = await crypto.subtle.exportKey(
  "jwk",
  publicKey,
);

Derive bits

const derivedBits = await crypto.subtle.deriveBits(
  {
    name: "ECDH",
    public: publicKey,
  },
  privateKey,
  128,
);

Derive key

const derivedKey = await crypto.subtle.deriveKey(
  {
    name: "ECDH",
    public: publicKey,
  },
  privateKey,
  {
    name: "AES-CBC",
    length: 128,
  },
  false,
  ["encrypt", "decrypt"],
);