readKey = function(path) {
    var data = fs.readFileSync(path, 'utf-8');
    var result =
        global.e2e.openpgp.block.factory.parseAsciiAllTransferableKeys(data);
    assert.equal(result.length, 1);
    var key = result[0];
    key.processSignatures();
    return key;
  }
Helper function that reads a public/private key.
@param {string} path The path to the key file.
@return {!e2e.openpgp.block.TransferableKey} A validated key from the file.