code: func (e *Engine) Verify(ctx context.Context, s SignatureKeyPair, b, sig []byte) (bool, error) {
  	err := ctxutil.ErrIfDone(ctx)
  	if err != nil {
  		return false, err
  	}
  
  	return ed25519.Verify(s.Public, b, sig), nil
  }
docs: // Verify verifies that sig is the correct signature for b given
  // SignatureKeyPair s.