newGCM(g *GCM, cipher *aes.Block, nonceSize, tagSize int) (*GCM, error) { if tagSize < gcmMinimumTagSize || tagSize > gcmBlockSize { return nil, errors.New("cipher: incorrect tag size given to GCM") } if nonceSize <= 0 { return nil, errors.New("cipher: the nonce can't have zero length") } if cipher.BlockSize() != gcmBlockSize { return nil, errors.New("cipher: NewGCM requires 128-bit block cipher") } g.cipher = *cipher g.nonceSize = nonceSize g.tagSize = tagSize initGCM(g) return g, nil } const ( gcmBlockSize...