/
WXBizMsgCrypt4Go.go
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/
WXBizMsgCrypt4Go.go
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// MIT License
//
// Copyright (c) 2021 co60
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
package WXBizMsgCrypt4Go
import (
"crypto/aes"
"crypto/cipher"
"crypto/sha1"
"encoding/base64"
"encoding/binary"
"encoding/xml"
"fmt"
"io"
"log"
"math/rand"
"sort"
"strings"
"time"
)
const AES_Block_Size int32 = 32
const EncodingAESKeyLen int32 = 16
const DataLengthLen uint32 = 4
type AES_Mode int
const (
AES_MODE_ECB AES_Mode = 1
AES_MODE_CBC AES_Mode = 2
AES_MODE_CFB AES_Mode = 3
AES_MODE_OFB AES_Mode = 5
AES_MODE_CTR AES_Mode = 6
AES_MODE_OPENPGP AES_Mode = 7
AES_MODE_CCM AES_Mode = 8
AES_MODE_EAX AES_Mode = 9
AES_MODE_SIV AES_Mode = 10
AES_MODE_GCM AES_Mode = 11
AES_MODE_OCB AES_Mode = 12
)
type WXBizMsgCryptErr int32
const (
WXBizMsgCrypt_OK WXBizMsgCryptErr = 0
WXBizMsgCrypt_ValidateSignatureError WXBizMsgCryptErr = -40001
WXBizMsgCrypt_ParseXmlError WXBizMsgCryptErr = -40002
WXBizMsgCrypt_ComputeSignatureError WXBizMsgCryptErr = -40003
WXBizMsgCrypt_IllegalAesKey WXBizMsgCryptErr = -40004
WXBizMsgCrypt_ValidateAppidError WXBizMsgCryptErr = -40005
WXBizMsgCrypt_EncryptAESError WXBizMsgCryptErr = -40006
WXBizMsgCrypt_DecryptAESError WXBizMsgCryptErr = -40007
WXBizMsgCrypt_IllegalBuffer WXBizMsgCryptErr = -40008
WXBizMsgCrypt_EncodeBase64Error WXBizMsgCryptErr = -40009
WXBizMsgCrypt_DecodeBase64Error WXBizMsgCryptErr = -40010
WXBizMsgCrypt_GenReturnXmlError WXBizMsgCryptErr = -40011
)
func GetErrMessage(errcode WXBizMsgCryptErr) string {
switch errcode {
case WXBizMsgCrypt_ValidateSignatureError:
return "签名验证错误"
case WXBizMsgCrypt_IllegalAesKey:
return "SymmetricKey非法"
case WXBizMsgCrypt_ValidateAppidError:
return "appid校验失败"
case WXBizMsgCrypt_EncryptAESError:
return "aes加密失败"
case WXBizMsgCrypt_DecryptAESError:
return "aes解密失败"
case WXBizMsgCrypt_ParseXmlError:
return "xml解析失败"
case WXBizMsgCrypt_IllegalBuffer:
return "解密后得到的buffer非法"
case WXBizMsgCrypt_EncodeBase64Error:
return "base64加密错误"
case WXBizMsgCrypt_DecodeBase64Error:
return "base64解密错误"
case WXBizMsgCrypt_GenReturnXmlError:
return "xml生成失败"
default:
return "成功"
}
}
type SHA1 struct{}
func (hashlib SHA1) getSHA1(token, timestamp, nonce, encrypt string) (string, WXBizMsgCryptErr) {
sortlist := []string{token, timestamp, nonce, encrypt}
sort.Strings(sortlist)
hashmaker := sha1.New()
_, err := io.WriteString(hashmaker, strings.Join(sortlist, ""))
if err != nil {
return "", WXBizMsgCrypt_ComputeSignatureError
}
hashBytes := hashmaker.Sum(nil)
return fmt.Sprintf("%x", hashBytes), WXBizMsgCrypt_OK
}
type CDATA struct {
Text string `xml:",cdata"`
}
/**
* `<xml>
* <Encrypt><![CDATA[%(msg_encrypt)s]]></Encrypt>
* <MsgSignature><![CDATA[%(msg_signaturet)s]]></MsgSignature>
* <TimeStamp>%(timestamp)s</TimeStamp>
* <Nonce><![CDATA[%(nonce)s]]></Nonce>
* </xml>`
*/
type AesTextResp struct {
XMLName xml.Name `xml:"xml"`
MsgEncrypt CDATA `xml:"Encrypt"`
MsgSignature CDATA `xml:"MsgSignature"`
TimeStamp string `xml:"TimeStamp"`
Nonce CDATA `xml:"Nonce"`
}
/**
* <xml><ToUserName><![CDATA[gh_10f6c3c3ac5a]]></ToUserName>
* <FromUserName><![CDATA[oyORnuP8q7ou2gfYjqLzSIWZf0rs]]></FromUserName>
* <CreateTime>1409735668</CreateTime>
* <MsgType><![CDATA[text]]></MsgType>
* <Content><![CDATA[abcdteT]]></Content>
* <MsgId>6054768590064713728</MsgId>
* </xml>
*/
type TextMsg struct {
XMLName xml.Name `xml:"xml"`
ToUserName CDATA `xml:"ToUserName"`
CreateTime CDATA `xml:"CreateTime"`
MsgType CDATA `xml:"MsgType"`
Content CDATA `xml:"Content"`
Encrypt CDATA `xml:"Encrypt"`
MsgId CDATA `xml:"MsgId"`
}
type XMLParse struct{}
func (parse XMLParse) extract(xmltext string) (string, string, WXBizMsgCryptErr) {
v := TextMsg{
ToUserName: CDATA{""},
}
err := xml.Unmarshal([]byte(xmltext), &v)
if err != nil {
log.Printf("%s\n", err.Error())
return "", "", WXBizMsgCrypt_ParseXmlError
}
return v.Encrypt.Text, v.ToUserName.Text, WXBizMsgCrypt_OK
}
func (parse XMLParse) generate(encrypt, signature, timestamp, nonce string) string {
msg := AesTextResp{
MsgEncrypt: CDATA{encrypt},
MsgSignature: CDATA{signature},
TimeStamp: timestamp,
Nonce: CDATA{nonce},
}
// respBytes, err := xml.Marshal(msg)
respBytes, err := xml.MarshalIndent(msg, "", "\r")
if err != nil {
log.Printf("generate xml error: %s, xml param: %+v\n", err, msg)
}
resp_xml := string(respBytes)
log.Printf("xml: %s\n", resp_xml)
return string(resp_xml)
}
type PKCS7Encoder struct {
BlockSize int
}
func NewDefaultPKCS7Encoder() PKCS7Encoder {
return PKCS7Encoder{32}
}
/**
* 对需要加密的明文进行填充补位
* @param text: 需要进行填充补位操作的明文
* @return: 补齐明文字符串
*/
func (encoder PKCS7Encoder) encode(text []byte) []byte {
text_length := len(text)
amount_to_pad := encoder.BlockSize - (text_length % encoder.BlockSize)
if amount_to_pad == 0 {
amount_to_pad = encoder.BlockSize
}
pad := byte(amount_to_pad)
resultBytes := make([]byte, text_length+amount_to_pad)
copy(resultBytes, text)
for i := 0; i < amount_to_pad; i++ {
resultBytes[i+text_length] = pad
}
return resultBytes
}
/**
* 删除解密后明文的补位字符
* @param decrypted: 解密后的明文
* @return: 删除补位字符后的明文
*/
func (encoder PKCS7Encoder) decode(decrypted []byte) []byte {
length := len(decrypted)
if length > 0 {
unPadding := int(decrypted[length-1])
return decrypted[:(length - unPadding)]
}
return decrypted
}
type Prpcrypt struct {
Key []byte
Mode AES_Mode
}
/**
* 随机生成16位字符串
* @return: 16位字符串
*/
func (pc Prpcrypt) get_random_str() string {
length := 16
str := "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
bytes := []byte(str)
result := []byte{}
r := rand.New(rand.NewSource(time.Now().UnixNano()))
for i := 0; i < length; i++ {
result = append(result, bytes[r.Intn(len(bytes))])
}
return string(result)
}
/**
* 对明文进行加密
* @param text: 需要加密的明文
* @return: 加密得到的字符串
*/
func (pc Prpcrypt) encrypt(rawData string, appid string) (string, WXBizMsgCryptErr) {
bs := make([]byte, 4)
binary.BigEndian.PutUint32(bs, uint32(len(rawData)))
text := pc.get_random_str() + string(bs) + rawData + appid
var plainTextBytes []byte = []byte(text)
pkcs7 := NewDefaultPKCS7Encoder()
plainTextBytes = pkcs7.encode(plainTextBytes)
cryptor, errCipher := aes.NewCipher(pc.Key)
if errCipher != nil {
return "", WXBizMsgCrypt_EncryptAESError
}
encrypter := cipher.NewCBCEncrypter(cryptor, pc.Key[:EncodingAESKeyLen])
encrypter.CryptBlocks(plainTextBytes, plainTextBytes)
resultData := base64.StdEncoding.EncodeToString(plainTextBytes)
return resultData, WXBizMsgCrypt_OK
}
/**
* 对解密后的明文进行补位删除
* @param encryptedData: 密文
* @param appid: 小程序AppId
* @return: 删除填充补位后的明文
*/
func (pc Prpcrypt) decrypt(encryptedData string, appid string) (string, WXBizMsgCryptErr) {
cryptor, errCipher := aes.NewCipher(pc.Key)
if errCipher != nil {
return "", WXBizMsgCrypt_DecryptAESError
}
cipherTextBytes, errChipherText := base64.StdEncoding.DecodeString(encryptedData)
if errChipherText != nil {
return "", WXBizMsgCrypt_DecodeBase64Error
}
plainTextBytes := make([]byte, len(cipherTextBytes))
decrypter := cipher.NewCBCDecrypter(cryptor, pc.Key[:EncodingAESKeyLen])
decrypter.CryptBlocks(plainTextBytes, cipherTextBytes)
pkcs7Encoder := NewDefaultPKCS7Encoder()
plainTextBytes = pkcs7Encoder.decode(plainTextBytes)
plainTextBytes = plainTextBytes[EncodingAESKeyLen:]
plainTextBytesLen := plainTextBytes[:DataLengthLen]
rawLen := binary.BigEndian.Uint32(plainTextBytesLen)
resultBytes := plainTextBytes[DataLengthLen : rawLen+DataLengthLen]
// rawAppId := plainTextBytes[rawLen+4:]
// fmt.Printf("raw AppId is %s\n", string(rawAppId))
return string(resultBytes), WXBizMsgCrypt_OK
}
type WXBizMsgCrypt struct {
Token string
Key []byte
Appid string
Format string // json or xml (default) format output
IgnSig bool // ignore signature validation (just in test mode)
}
func NewDefaultWXBizMsgCrypt(token, keyStr, appid string) WXBizMsgCrypt {
keyBytes, _ := base64.StdEncoding.DecodeString(keyStr + "=")
return WXBizMsgCrypt{token, keyBytes, appid, "xml", false}
}
func NewWXBizMsgCrypt(token, keyStr, appid, format string) WXBizMsgCrypt {
keyBytes, _ := base64.StdEncoding.DecodeString(keyStr + "=")
if strings.ToLower(format) != "xml" {
return WXBizMsgCrypt{token, keyBytes, appid, "json", false}
}
return WXBizMsgCrypt{token, keyBytes, appid, "xml", false}
}
func NewTestWXBizMsgCrypt(token, keyStr, appid, format string, ignoreSig bool) WXBizMsgCrypt {
keyBytes, _ := base64.StdEncoding.DecodeString(keyStr + "=")
return WXBizMsgCrypt{token, keyBytes, appid, format, ignoreSig}
}
func (wxcrypt WXBizMsgCrypt) EncryptMsg(replyData string, nonce string, timestamp string) (string, WXBizMsgCryptErr) {
pc := Prpcrypt{wxcrypt.Key, AES_MODE_CBC}
encrypt, errcode := pc.encrypt(replyData, wxcrypt.Appid)
if errcode != WXBizMsgCrypt_OK {
return "", errcode
}
if timestamp == "" {
timestamp = fmt.Sprintf("%d", time.Now().Unix())
}
// xml processes
if wxcrypt.Format == "xml" {
hashlib := SHA1{}
signature, err := hashlib.getSHA1(wxcrypt.Token, timestamp, nonce, encrypt)
if err != WXBizMsgCrypt_OK {
log.Printf("%s", GetErrMessage(WXBizMsgCrypt_OK))
return "", err
}
xmlParse := XMLParse{}
encrypt = xmlParse.generate(encrypt, signature, timestamp, nonce)
return encrypt, WXBizMsgCrypt_OK
}
return encrypt, WXBizMsgCrypt_OK
}
func (wxcrypt WXBizMsgCrypt) DecryptMsg(postData string, msgSignature string, timestamp string, nonce string) (string, WXBizMsgCryptErr) {
encrypt := postData
// xml processes
toUserName := ""
if wxcrypt.Format == "xml" {
xmlParse := XMLParse{}
encrypt_data, touser_name, ret := xmlParse.extract(postData)
if ret != WXBizMsgCrypt_OK {
return "", WXBizMsgCrypt_ParseXmlError
}
encrypt = encrypt_data
toUserName = touser_name
log.Printf("\nDecrypt message to user name: %s\n", toUserName)
}
hashlib := SHA1{}
signature, errcode := hashlib.getSHA1(wxcrypt.Token, timestamp, nonce, encrypt)
if errcode != WXBizMsgCrypt_OK {
return "", errcode
}
if !wxcrypt.IgnSig && signature != msgSignature {
return "", WXBizMsgCrypt_ValidateSignatureError
}
pc := Prpcrypt{wxcrypt.Key, AES_MODE_CBC}
raw, ec := pc.decrypt(encrypt, wxcrypt.Appid)
return raw, ec
}
func RemoveSurplusCharactorsInXmlOrJson(src string) string {
dst := src
dst = strings.Replace(dst, " ", "", -1)
dst = strings.Replace(dst, "\n", "", -1)
dst = strings.Replace(dst, "\r", "", -1)
return dst
}
// func IsLittleEndian() bool {
// var i int32 = 0x01020304
// u := unsafe.Pointer(&i)
// pb := (*byte)(u)
// b := *pb
// return (b == 0x04)
// }