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Better API #8

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Nov 27, 2023
Merged

Better API #8

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41 changes: 33 additions & 8 deletions example_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -2,20 +2,20 @@ package otp_test

import (
"fmt"
"time"

"github.com/cristalhq/otp"
)

func Example() {
secretInBase32 := "JBSWY3DPEHPK3PXP"

algo := otp.AlgorithmSHA1
digits := otp.Digits(10)
issuer := "cristalhq"

hotp, err := otp.NewHOTP(algo, digits, issuer)
func ExampleHOTP() {
hotp, err := otp.NewHOTP(otp.HOTPConfig{
Algo: otp.AlgorithmSHA1,
Digits: otp.Digits(10),
Issuer: "cristalhq",
})
checkErr(err)

secretInBase32 := "JBSWY3DPEHPK3PXP"
code, err := hotp.GenerateCode(42, secretInBase32)
checkErr(err)

Expand All @@ -28,6 +28,31 @@ func Example() {
// 0979090604
}

func ExampleTOTP() {
totp, err := otp.NewTOTP(otp.TOTPConfig{
Algo: otp.AlgorithmSHA1,
Digits: otp.Digits(10),
Issuer: "cristalhq",
Period: 30,
Skew: 2,
})
checkErr(err)

secretInBase32 := "JBSWY3DPEHPK3PXP"
at := time.Date(2023, 11, 26, 12, 15, 18, 0, time.UTC)

code, err := totp.GenerateCode(secretInBase32, at)
checkErr(err)

fmt.Println(code)

err = totp.Validate(code, at, secretInBase32)
checkErr(err)

// Output:
// 0462778229
}

func checkErr(err error) {
if err != nil {
panic(err)
Expand Down
52 changes: 30 additions & 22 deletions hotp.go
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Original file line number Diff line number Diff line change
Expand Up @@ -10,38 +10,46 @@ import (

// HOTP represents HOTP codes generator and validator.
type HOTP struct {
algo Algorithm
digits Digits
issuer string
cfg HOTPConfig
}

// NewHOTP creates new HOTP.
func NewHOTP(algo Algorithm, digits Digits, issuer string) (*HOTP, error) {
if algo < 0 || algo >= algorithmMax {
return nil, ErrUnsupportedAlgorithm
type HOTPConfig struct {
Algo Algorithm
Digits Digits
Issuer string
}
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func (cfg HOTPConfig) Validate() error {
switch {
case cfg.Algo < 0 || cfg.Algo >= algorithmMax:
return ErrUnsupportedAlgorithm
case cfg.Issuer == "":
return ErrEmptyIssuer
default:
return nil
}
if issuer == "" {
return nil, ErrEmptyIssuer
}

// NewHOTP creates new HOTP.
func NewHOTP(cfg HOTPConfig) (*HOTP, error) {
if err := cfg.Validate(); err != nil {
return nil, err
}
return &HOTP{
algo: algo,
digits: digits,
issuer: issuer,
}, nil
return &HOTP{cfg: cfg}, nil
}

// GenerateURL for the account for a given secret.
func (h *HOTP) GenerateURL(account string, secret []byte) string {
v := url.Values{}
v.Set("algorithm", h.algo.String())
v.Set("digits", h.digits.String())
v.Set("issuer", h.issuer)
v.Set("algorithm", h.cfg.Algo.String())
v.Set("digits", h.cfg.Digits.String())
v.Set("issuer", h.cfg.Issuer)
v.Set("secret", b32EncNoPadding(secret))

u := url.URL{
Scheme: "otpauth",
Host: "hotp",
Path: "/" + h.issuer + ":" + account,
Path: "/" + h.cfg.Issuer + ":" + account,
RawQuery: v.Encode(),
}
return u.String()
Expand All @@ -57,7 +65,7 @@ func (h *HOTP) GenerateCode(counter uint64, secret string) (string, error) {
buf := make([]byte, 8)
binary.BigEndian.PutUint64(buf, counter)

mac := hmac.New(h.algo.Hash, secretBytes)
mac := hmac.New(h.cfg.Algo.Hash, secretBytes)
mac.Write(buf)
sum := mac.Sum(nil)

Expand All @@ -69,13 +77,13 @@ func (h *HOTP) GenerateCode(counter uint64, secret string) (string, error) {
value |= int64(sum[offset+2]&0xff) << 8
value |= int64(sum[offset+3] & 0xff)

length := int64(math.Pow10(h.digits.Length()))
return h.digits.Format(int(value % length)), nil
length := int64(math.Pow10(h.cfg.Digits.Length()))
return h.cfg.Digits.Format(int(value % length)), nil
}

// Validate the given passcode, counter and secret.
func (h *HOTP) Validate(passcode string, counter uint64, secret string) error {
if len(passcode) != h.digits.Length() {
if len(passcode) != h.cfg.Digits.Length() {
return ErrCodeLengthMismatch
}

Expand Down
42 changes: 35 additions & 7 deletions hotp_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,11 @@ func TestHOTP(t *testing.T) {
}

for _, tc := range hotpRFCTestCases {
hotp, err := NewHOTP(tc.algo, Digits(6), "cristalhq")
hotp, err := NewHOTP(HOTPConfig{
Algo: tc.algo,
Digits: Digits(6),
Issuer: "cristalhq",
})
mustOk(t, err)

code, err := hotp.GenerateCode(tc.counter, tc.secret)
Expand All @@ -38,15 +42,27 @@ func TestHOTP(t *testing.T) {
}

func TestNewHOTP(t *testing.T) {
_, err := NewHOTP(-1, Digits(8), "cristalhq")
_, err := NewHOTP(HOTPConfig{
Algo: -1,
Digits: Digits(8),
Issuer: "cristalhq",
})
mustEqual(t, err, ErrUnsupportedAlgorithm)

_, err = NewHOTP(1, Digits(8), "")
_, err = NewHOTP(HOTPConfig{
Algo: 1,
Digits: Digits(8),
Issuer: "",
})
mustEqual(t, err, ErrEmptyIssuer)
}

func TestHOTPGenerateURL(t *testing.T) {
hotp, err := NewHOTP(AlgorithmSHA1, Digits(8), "cristalhq")
hotp, err := NewHOTP(HOTPConfig{
Algo: AlgorithmSHA1,
Digits: Digits(8),
Issuer: "cristalhq",
})
mustOk(t, err)

url := hotp.GenerateURL("alice@bob.com", []byte("SECRET_STRING"))
Expand All @@ -57,7 +73,11 @@ func TestHOTPGenerateURL(t *testing.T) {
}

func BenchmarkHOTP_GenerateURL(b *testing.B) {
hotp, err := NewHOTP(AlgorithmSHA1, Digits(8), "cristalhq")
hotp, err := NewHOTP(HOTPConfig{
Algo: AlgorithmSHA1,
Digits: Digits(8),
Issuer: "cristalhq",
})
mustOk(b, err)

account := "otp@cristalhq.dev"
Expand All @@ -75,7 +95,11 @@ func BenchmarkHOTP_GenerateURL(b *testing.B) {
}

func BenchmarkHOTP_GenerateCode(b *testing.B) {
hotp, err := NewHOTP(AlgorithmSHA1, Digits(8), "cristalhq")
hotp, err := NewHOTP(HOTPConfig{
Algo: AlgorithmSHA1,
Digits: Digits(8),
Issuer: "cristalhq",
})
mustOk(b, err)

b.ResetTimer()
Expand All @@ -90,7 +114,11 @@ func BenchmarkHOTP_GenerateCode(b *testing.B) {
}

func BenchmarkHOTP_Validate(b *testing.B) {
hotp, err := NewHOTP(AlgorithmSHA1, Digits(8), "cristalhq")
hotp, err := NewHOTP(HOTPConfig{
Algo: AlgorithmSHA1,
Digits: Digits(8),
Issuer: "cristalhq",
})
mustOk(b, err)

secret := secretSha1
Expand Down
74 changes: 43 additions & 31 deletions totp.go
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Original file line number Diff line number Diff line change
Expand Up @@ -9,59 +9,71 @@ import (

// TOTP represents TOTP codes generator and validator.
type TOTP struct {
*HOTP
period uint
skew uint
hotp HOTP
cfg TOTPConfig
}

// NewTOTP creates new TOTP.
func NewTOTP(algo Algorithm, digits Digits, issuer string, period, skew uint) (*TOTP, error) {
if algo < 0 || algo >= algorithmMax {
return nil, ErrUnsupportedAlgorithm
}
if issuer == "" {
return nil, ErrEmptyIssuer
}
if period < 1 {
return nil, ErrPeriodNotValid
type TOTPConfig struct {
Algo Algorithm
Digits Digits
Issuer string
Period uint
Skew uint
}

func (cfg TOTPConfig) Validate() error {
switch {
case cfg.Algo < 0 || cfg.Algo >= algorithmMax:
return ErrUnsupportedAlgorithm
case cfg.Issuer == "":
return ErrEmptyIssuer
default:
return nil
}
if skew < 1 {
return nil, ErrSkewNotValid
}

// NewTOTP creates new TOTP.
func NewTOTP(cfg TOTPConfig) (*TOTP, error) {
if err := cfg.Validate(); err != nil {
return nil, err
}

hotp, err := NewHOTP(algo, digits, issuer)
hotp, err := NewHOTP(HOTPConfig{
Algo: cfg.Algo,
Digits: cfg.Digits,
Issuer: cfg.Issuer,
})
if err != nil {
return nil, err
}
return &TOTP{
HOTP: hotp,
period: period,
skew: skew,
hotp: *hotp,
cfg: cfg,
}, nil
}

// GenerateURL for the account for a given secret.
func (t *TOTP) GenerateURL(account string, secret []byte) string {
v := url.Values{}
v.Set("algorithm", t.algo.String())
v.Set("digits", t.digits.String())
v.Set("issuer", t.issuer)
v.Set("algorithm", t.cfg.Algo.String())
v.Set("digits", t.cfg.Digits.String())
v.Set("issuer", t.cfg.Issuer)
v.Set("secret", b32EncNoPadding(secret))
v.Set("period", strconv.FormatUint(uint64(t.period), 10))
v.Set("period", strconv.FormatUint(uint64(t.cfg.Period), 10))

u := url.URL{
Scheme: "otpauth",
Host: "totp",
Path: "/" + t.issuer + ":" + account,
Path: "/" + t.cfg.Issuer + ":" + account,
RawQuery: v.Encode(),
}
return u.String()
}

// GenerateCode for the given counter and secret.
func (t *TOTP) GenerateCode(secret string, at time.Time) (string, error) {
counter := uint64(math.Floor(float64(at.Unix()) / float64(t.period)))
code, err := t.HOTP.GenerateCode(counter, secret)
counter := uint64(math.Floor(float64(at.Unix()) / float64(t.cfg.Period)))
code, err := t.hotp.GenerateCode(counter, secret)
if err != nil {
return "", err
}
Expand All @@ -70,20 +82,20 @@ func (t *TOTP) GenerateCode(secret string, at time.Time) (string, error) {

// Validate the given passcode, time and secret.
func (t *TOTP) Validate(passcode string, at time.Time, secret string) error {
if len(passcode) != t.digits.Length() {
if len(passcode) != t.cfg.Digits.Length() {
return ErrCodeLengthMismatch
}

counters := make([]uint64, 0, 2*t.skew+1)
counter := int64(math.Floor(float64(at.Unix()) / float64(t.period)))
counters := make([]uint64, 0, 2*t.cfg.Skew+1)
counter := int64(math.Floor(float64(at.Unix()) / float64(t.cfg.Period)))
counters = append(counters, uint64(counter))

for i := uint(1); i <= t.skew; i++ {
for i := uint(1); i <= t.cfg.Skew; i++ {
counters = append(counters, uint64(counter+int64(i)), uint64(counter-int64(i)))
}

for _, counter := range counters {
err := t.HOTP.Validate(passcode, counter, secret)
err := t.hotp.Validate(passcode, counter, secret)
if err == nil {
return nil
}
Expand Down
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