errOpen = errors.New("cipher: message authentication failed") func (g *GCM) Open(dst, nonce, ciphertext, data []byte) ([]byte, error) { if len(nonce) != g.nonceSize { panic("crypto/cipher: incorrect nonce length given to GCM") } // Sanity check to prevent the authentication from always succeeding if an // implementation leaves tagSize uninitialized, for example. if g.tagSize < gcmMinimumTagSize { panic("crypto/cipher: incorrect GCM tag size") } if len(ciphertext) < g.tagSize { return nil, errOpen }...