code: function validate(actual, token, alg) {
    assert.equal(arguments.length, 3, 'three arguments required');
  
    if (!actual || !token) return false;
    return generate(token, getSHAsize(alg)) === actual;
  }
docs: @name validate
  @api public
  
  Validates the provided _hash value is matching the token and appropriate alg value
  
  @param actual {String} _hash value from an ID Token
  @param token {String} token value
  @param alg {String} ID Token JOSE header alg value (i.e. RS256, HS384, ES512, PS256)