func (mgm *MGM) Open(dst, nonce, ciphertext, additionalData []byte) ([]byte, error) {
mgm.validateNonce(nonce)
mgm.validateSizes(ciphertext, additionalData)
func (mgm *MGM) Open(dst, nonce, ciphertext, additionalData []byte) ([]byte, error) {
mgm.validateNonce(nonce)
mgm.validateSizes(ciphertext, additionalData)