github.com/icodeface/tls@v0.0.0-20230910023335-34df9250cd12/internal/x/crypto/chacha20poly1305/chacha20poly1305_amd64.go (about)

     1  // Copyright 2016 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build go1.7 && amd64 && !gccgo && !appengine
     6  // +build go1.7,amd64,!gccgo,!appengine
     7  
     8  package chacha20poly1305
     9  
    10  import (
    11  	"encoding/binary"
    12  
    13  	"github.com/icodeface/tls/internal/cpu"
    14  )
    15  
    16  //go:noescape
    17  func chacha20Poly1305Open(dst []byte, key []uint32, src, ad []byte) bool
    18  
    19  //go:noescape
    20  func chacha20Poly1305Seal(dst []byte, key []uint32, src, ad []byte)
    21  
    22  var (
    23  	useASM  = cpu.X86.HasSSSE3
    24  	useAVX2 = cpu.X86.HasAVX2 && cpu.X86.HasBMI2
    25  )
    26  
    27  // setupState writes a ChaCha20 input matrix to state. See
    28  // https://tools.ietf.org/html/rfc7539#section-2.3.
    29  func setupState(state *[16]uint32, key *[8]uint32, nonce []byte) {
    30  	state[0] = 0x61707865
    31  	state[1] = 0x3320646e
    32  	state[2] = 0x79622d32
    33  	state[3] = 0x6b206574
    34  
    35  	state[4] = key[0]
    36  	state[5] = key[1]
    37  	state[6] = key[2]
    38  	state[7] = key[3]
    39  	state[8] = key[4]
    40  	state[9] = key[5]
    41  	state[10] = key[6]
    42  	state[11] = key[7]
    43  
    44  	state[12] = 0
    45  	state[13] = binary.LittleEndian.Uint32(nonce[:4])
    46  	state[14] = binary.LittleEndian.Uint32(nonce[4:8])
    47  	state[15] = binary.LittleEndian.Uint32(nonce[8:12])
    48  }
    49  
    50  func (c *chacha20poly1305) seal(dst, nonce, plaintext, additionalData []byte) []byte {
    51  	if !useASM {
    52  		return c.sealGeneric(dst, nonce, plaintext, additionalData)
    53  	}
    54  
    55  	var state [16]uint32
    56  	setupState(&state, &c.key, nonce)
    57  
    58  	ret, out := sliceForAppend(dst, len(plaintext)+16)
    59  	chacha20Poly1305Seal(out[:], state[:], plaintext, additionalData)
    60  	return ret
    61  }
    62  
    63  func (c *chacha20poly1305) open(dst, nonce, ciphertext, additionalData []byte) ([]byte, error) {
    64  	if !useASM {
    65  		return c.openGeneric(dst, nonce, ciphertext, additionalData)
    66  	}
    67  
    68  	var state [16]uint32
    69  	setupState(&state, &c.key, nonce)
    70  
    71  	ciphertext = ciphertext[:len(ciphertext)-16]
    72  	ret, out := sliceForAppend(dst, len(ciphertext))
    73  	if !chacha20Poly1305Open(out, state[:], ciphertext, additionalData) {
    74  		for i := range out {
    75  			out[i] = 0
    76  		}
    77  		return nil, errOpen
    78  	}
    79  
    80  	return ret, nil
    81  }