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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build amd64 arm64
package aes
import (
"crypto/cipher"
"crypto/internal/subtle"
"internal/cpu"
)
// defined in asm_*.s
//go:noescape
func encryptBlockAsm(nr int, xk *uint32, dst, src *byte)
//go:noescape
func decryptBlockAsm(nr int, xk *uint32, dst, src *byte)
//go:noescape
func expandKeyAsm(nr int, key *byte, enc *uint32, dec *uint32)
type aesCipherAsm struct {
aesCipher
}
var supportsAES = cpu.X86.HasAES || cpu.ARM64.HasAES
var supportsGFMUL = cpu.X86.HasPCLMULQDQ || cpu.ARM64.HasPMULL
func newCipher(key []byte) (cipher.Block, error) {
if !supportsAES {
return newCipherGeneric(key)
}
n := len(key) + 28
c := aesCipherAsm{aesCipher{make([]uint32, n), make([]uint32, n)}}
var rounds int
switch len(key) {
case 128 / 8:
rounds = 10
case 192 / 8:
rounds = 12
case 256 / 8:
rounds = 14
}
expandKeyAsm(rounds, &key[0], &c.enc[0], &c.dec[0])
if supportsAES && supportsGFMUL {
return &aesCipherGCM{c}, nil
}
return &c, nil
}
func (c *aesCipherAsm) BlockSize() int { return BlockSize }
func (c *aesCipherAsm) Encrypt(dst, src []byte) {
if len(src) < BlockSize {
panic("crypto/aes: input not full block")
}
if len(dst) < BlockSize {
panic("crypto/aes: output not full block")
}
if subtle.InexactOverlap(dst[:BlockSize], src[:BlockSize]) {
panic("crypto/aes: invalid buffer overlap")
}
encryptBlockAsm(len(c.enc)/4-1, &c.enc[0], &dst[0], &src[0])
}
func (c *aesCipherAsm) Decrypt(dst, src []byte) {
if len(src) < BlockSize {
panic("crypto/aes: input not full block")
}
if len(dst) < BlockSize {
panic("crypto/aes: output not full block")
}
if subtle.InexactOverlap(dst[:BlockSize], src[:BlockSize]) {
panic("crypto/aes: invalid buffer overlap")
}
decryptBlockAsm(len(c.dec)/4-1, &c.dec[0], &dst[0], &src[0])
}
// expandKey is used by BenchmarkExpand to ensure that the asm implementation
// of key expansion is used for the benchmark when it is available.
func expandKey(key []byte, enc, dec []uint32) {
if supportsAES {
rounds := 10 // rounds needed for AES128
switch len(key) {
case 192 / 8:
rounds = 12
case 256 / 8:
rounds = 14
}
expandKeyAsm(rounds, &key[0], &enc[0], &dec[0])
} else {
expandKeyGo(key, enc, dec)
}
}