gmsm/cipher/gcm.go

// Copyright 2024 Sun Yimin. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.

//go:build purego || !s390x

package cipher

import (
	_cipher "crypto/cipher"
)

// A proxy of Golang cipher gcm mode.

// NewGCM returns the given 128-bit, block cipher wrapped in Galois Counter Mode
// with the standard nonce length.
//
// In general, the GHASH operation performed by this implementation of GCM is not constant-time.
// An exception is when the underlying Block was created by aes.NewCipher
// on systems with hardware support for AES. See the crypto/aes package documentation for details.
func NewGCM(cipher _cipher.Block) (_cipher.AEAD, error) {
	return _cipher.NewGCM(cipher)
}

// NewGCMWithNonceSize returns the given 128-bit, block cipher wrapped in Galois
// Counter Mode, which accepts nonces of the given length. The length must not
// be zero.
//
// Only use this function if you require compatibility with an existing
// cryptosystem that uses non-standard nonce lengths. All other users should use
// NewGCM, which is faster and more resistant to misuse.
func NewGCMWithNonceSize(cipher _cipher.Block, size int) (_cipher.AEAD, error) {
	return _cipher.NewGCMWithNonceSize(cipher, size)
}

// NewGCMWithTagSize returns the given 128-bit, block cipher wrapped in Galois
// Counter Mode, which generates tags with the given length.
//
// Tag sizes between 12 and 16 bytes are allowed.
//
// Only use this function if you require compatibility with an existing
// cryptosystem that uses non-standard tag lengths. All other users should use
// NewGCM, which is more resistant to misuse.
func NewGCMWithTagSize(cipher _cipher.Block, tagSize int) (_cipher.AEAD, error) {
	return _cipher.NewGCMWithTagSize(cipher, tagSize)
}