ECDSA signature verification

Using ECDSA public key to verify signature

JavaScript

// From https://github.com/nodejs/node-v0.x-archive/issues/6904
var keys = {
  priv: '-----BEGIN EC PRIVATE KEY-----\n' +
        'MHcCAQEEIF+jnWY1D5kbVYDNvxxo/Y+ku2uJPDwS0r/VuPZQrjjVoAoGCCqGSM49\n' +
        'AwEHoUQDQgAEurOxfSxmqIRYzJVagdZfMMSjRNNhB8i3mXyIMq704m2m52FdfKZ2\n' +
        'pQhByd5eyj3lgZ7m7jbchtdgyOF8Io/1ng==\n' +
        '-----END EC PRIVATE KEY-----\n',
  pub: '-----BEGIN PUBLIC KEY-----\n' +
       'MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEurOxfSxmqIRYzJVagdZfMMSjRNNh\n' +
       'B8i3mXyIMq704m2m52FdfKZ2pQhByd5eyj3lgZ7m7jbchtdgyOF8Io/1ng==\n' +
       '-----END PUBLIC KEY-----\n'
};
var message = (new TextEncoder('UTF-8')).encode('hello');

// Algorithm used in Node.js script is ecdsa-with-SHA1, key generated with prime256v1
var algorithm = {
    name: 'ECDSA',
    namedCurve: 'P-256',
    hash: {
        name: 'SHA-1'
    }
};

// Signature from obtained via above Node.js script
var sig64 = 'MEUCIQDkAtiomagyHFi7dNfxMrzx/U0Gk/ZhmwCqaL3TimvlswIgPgeDqgZNqfR5/FZZASYsczUAhGSXjuycLhWnvk20qKc=';

// Decode base64 string into ArrayBuffer
var b64Decode = (str) => Uint8Array.from(atob(str), x => x.charCodeAt(0));

// Get base64 string from public key
const key64 = keys.pub.split('\n')
    .filter(x => x.length > 0 && !x.startsWith('-----'))
    .join('');

// Convert to buffers
var sig = b64Decode(sig64);
var keySpki = b64Decode(key64);

// Import and verify
// Expected: 'Verification result: false'
var importKey = crypto.subtle.importKey('spki', keySpki, algorithm, true, ['verify'])
    .then(key => crypto.subtle.verify(algorithm, key, sig, message))
    .then(result => console.log('Verification result: ' + result));