mirror of
https://github.com/silenceper/wechat.git
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120 lines
3.1 KiB
Go
120 lines
3.1 KiB
Go
package encryptor
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import (
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"crypto/aes"
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"crypto/cipher"
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"encoding/base64"
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"encoding/json"
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"errors"
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"github.com/silenceper/wechat/v2/miniprogram/context"
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)
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//Encryptor struct
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type Encryptor struct {
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*context.Context
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}
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//NewEncryptor 实例
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func NewEncryptor(context *context.Context) *Encryptor {
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basic := new(Encryptor)
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basic.Context = context
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return basic
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}
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var (
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// ErrAppIDNotMatch appid不匹配
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ErrAppIDNotMatch = errors.New("app id not match")
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// ErrInvalidBlockSize block size不合法
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ErrInvalidBlockSize = errors.New("invalid block size")
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// ErrInvalidPKCS7Data PKCS7数据不合法
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ErrInvalidPKCS7Data = errors.New("invalid PKCS7 data")
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// ErrInvalidPKCS7Padding 输入padding失败
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ErrInvalidPKCS7Padding = errors.New("invalid padding on input")
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)
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// PlainData 用户信息/手机号信息
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type PlainData struct {
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OpenID string `json:"openId"`
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UnionID string `json:"unionId"`
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NickName string `json:"nickName"`
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Gender int `json:"gender"`
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City string `json:"city"`
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Province string `json:"province"`
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Country string `json:"country"`
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AvatarURL string `json:"avatarUrl"`
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Language string `json:"language"`
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PhoneNumber string `json:"phoneNumber"`
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PurePhoneNumber string `json:"purePhoneNumber"`
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CountryCode string `json:"countryCode"`
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Watermark struct {
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Timestamp int64 `json:"timestamp"`
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AppID string `json:"appid"`
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} `json:"watermark"`
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}
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// pkcs7Unpad returns slice of the original data without padding
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func pkcs7Unpad(data []byte, blockSize int) ([]byte, error) {
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if blockSize <= 0 {
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return nil, ErrInvalidBlockSize
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}
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if len(data)%blockSize != 0 || len(data) == 0 {
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return nil, ErrInvalidPKCS7Data
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}
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c := data[len(data)-1]
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n := int(c)
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if n == 0 || n > len(data) {
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return nil, ErrInvalidPKCS7Padding
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}
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for i := 0; i < n; i++ {
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if data[len(data)-n+i] != c {
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return nil, ErrInvalidPKCS7Padding
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}
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}
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return data[:len(data)-n], nil
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}
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// getCipherText returns slice of the cipher text
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func getCipherText(sessionKey, encryptedData, iv string) ([]byte, error) {
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aesKey, err := base64.StdEncoding.DecodeString(sessionKey)
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if err != nil {
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return nil, err
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}
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cipherText, err := base64.StdEncoding.DecodeString(encryptedData)
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if err != nil {
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return nil, err
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}
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ivBytes, err := base64.StdEncoding.DecodeString(iv)
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if err != nil {
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return nil, err
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}
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block, err := aes.NewCipher(aesKey)
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if err != nil {
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return nil, err
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}
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mode := cipher.NewCBCDecrypter(block, ivBytes)
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mode.CryptBlocks(cipherText, cipherText)
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cipherText, err = pkcs7Unpad(cipherText, block.BlockSize())
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if err != nil {
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return nil, err
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}
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return cipherText, nil
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}
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// Decrypt 解密数据
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func (encryptor *Encryptor) Decrypt(sessionKey, encryptedData, iv string) (*PlainData, error) {
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cipherText, err := getCipherText(sessionKey, encryptedData, iv)
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if err != nil {
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return nil, err
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}
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var plainData PlainData
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err = json.Unmarshal(cipherText, &plainData)
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if err != nil {
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return nil, err
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}
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if plainData.Watermark.AppID != encryptor.AppID {
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return nil, ErrAppIDNotMatch
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}
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return &plainData, nil
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}
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