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December 18, 2018 11:52
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生成谷歌验证器
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| package tools | |
| // 谷歌验证 | |
| // clone from: https://github.com/928799934/googleAuthenticator | |
| import ( | |
| "crypto/hmac" | |
| "crypto/sha1" | |
| "encoding/base32" | |
| "encoding/hex" | |
| "errors" | |
| "fmt" | |
| "math" | |
| "math/rand" | |
| "strconv" | |
| "strings" | |
| "time" | |
| ) | |
| var ( | |
| ErrGaSecretLengthLss = errors.New("secret length lss 6 error") | |
| ErrGaSecretLength = errors.New("secret length error") | |
| ErrGaPaddingCharCount = errors.New("padding char count error") | |
| ErrGaPaddingCharLocation = errors.New("padding char Location error") | |
| ErrGaParam = errors.New("param error") | |
| ) | |
| var ( | |
| gaTable = []string{ | |
| "A", "B", "C", "D", "E", "F", "G", "H", // 7 | |
| "I", "J", "K", "L", "M", "N", "O", "P", // 15 | |
| "Q", "R", "S", "T", "U", "V", "W", "X", // 23 | |
| "Y", "Z", "2", "3", "4", "5", "6", "7", // 31 | |
| "=", // padding char | |
| } | |
| gaallowedValues = map[int]string{ | |
| 6: "======", | |
| 4: "====", | |
| 3: "===", | |
| 1: "=", | |
| 0: "", | |
| } | |
| gaHmacSha1 = func(key, data []byte) []byte { | |
| mac := hmac.New(sha1.New, key) | |
| mac.Write(data) | |
| return mac.Sum(nil) | |
| } | |
| ) | |
| func arrayFlip(oldArr []string) map[string]int { | |
| newArr := make(map[string]int, len(oldArr)) | |
| for key, value := range oldArr { | |
| newArr[value] = key | |
| } | |
| return newArr | |
| } | |
| type GAuth struct { | |
| codeLen float64 | |
| table map[string]int | |
| } | |
| func NewGAuth() *GAuth { | |
| return &GAuth{ | |
| codeLen: 6, | |
| table: arrayFlip(gaTable), | |
| } | |
| } | |
| // SetCodeLength Set the code length, should be >=6 | |
| func (this *GAuth) SetCodeLength(length float64) error { | |
| if length < 6 { | |
| return ErrGaSecretLengthLss | |
| } | |
| this.codeLen = length | |
| return nil | |
| } | |
| // CreateSecret create new secret | |
| // 16 characters, randomly chosen from the allowed base32 characters. | |
| func (this *GAuth) CreateSecret(lens ...int) (string, error) { | |
| var ( | |
| length int | |
| secret []string | |
| ) | |
| // init length | |
| switch len(lens) { | |
| case 0: | |
| length = 16 | |
| case 1: | |
| length = lens[0] | |
| default: | |
| return "", ErrGaParam | |
| } | |
| for i := 0; i < length; i++ { | |
| secret = append(secret, gaTable[rand.Intn(len(gaTable))]) | |
| } | |
| return strings.Join(secret, ""), nil | |
| } | |
| // VerifyCode Check if the code is correct. This will accept codes starting from $discrepancy*30sec ago to $discrepancy*30sec from now | |
| func (this *GAuth) VerifyCode(secret, code string, discrepancy int64) (bool, error) { | |
| // now time | |
| curTimeSlice := time.Now().Unix() / 30 | |
| for i := -discrepancy; i <= discrepancy; i++ { | |
| calculatedCode, err := this.GetCode(secret, curTimeSlice+i) | |
| if err != nil { | |
| return false, err | |
| } | |
| if calculatedCode == code { | |
| return true, nil | |
| } | |
| } | |
| return false, nil | |
| } | |
| // GetCode Calculate the code, with given secret and point in time | |
| func (this *GAuth) GetCode(secret string, timeSlices ...int64) (string, error) { | |
| var timeSlice int64 | |
| switch len(timeSlices) { | |
| case 0: | |
| timeSlice = time.Now().Unix() / 30 | |
| case 1: | |
| timeSlice = timeSlices[0] | |
| default: | |
| return "", ErrGaParam | |
| } | |
| secret = strings.ToUpper(secret) | |
| secretKey, err := base32.StdEncoding.DecodeString(secret) | |
| if err != nil { | |
| return "", err | |
| } | |
| tim, err := hex.DecodeString(fmt.Sprintf("%016x", timeSlice)) | |
| if err != nil { | |
| return "", err | |
| } | |
| hm := gaHmacSha1(secretKey, tim) | |
| offset := hm[len(hm)-1] & 0x0F | |
| hashpart := hm[offset : offset+4] | |
| value, err := strconv.ParseInt(hex.EncodeToString(hashpart), 16, 0) | |
| if err != nil { | |
| return "", err | |
| } | |
| value = value & 0x7FFFFFFF | |
| modulo := int64(math.Pow(10, this.codeLen)) | |
| format := fmt.Sprintf("%%0%dd", int(this.codeLen)) | |
| return fmt.Sprintf(format, value%modulo), nil | |
| } |
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