init

README.md

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+# totp

go.mod

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+module github.com/openp2p-cn/totp
+
+go 1.18

totp.go

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+// Time-based One-time Password
+package totp
+
+import (
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/binary"
+)
+
+const RelayTOTPStep = 30
+const ForgotPwdTOTPStep = 300
+
+type TOTP struct {
+	Step int64 // relay 30s; forgot password 300s;
+}
+
+func (t *TOTP) Gen(token uint64, ts int64) uint64 {
+	step := ts / t.Step
+	tbuff := make([]byte, 8)
+	binary.LittleEndian.PutUint64(tbuff, token)
+	mac := hmac.New(sha256.New, tbuff)
+	b := make([]byte, 8)
+	binary.LittleEndian.PutUint64(b, uint64(step))
+	mac.Write(b)
+	num := binary.LittleEndian.Uint64(mac.Sum(nil)[:8])
+	// fmt.Printf("%x\n", mac.Sum(nil))
+	return num
+}
+
+func (t *TOTP) Verify(code uint64, token uint64, ts int64) bool {
+	if code == 0 {
+		return false
+	}
+	if code == token {
+		return true
+	}
+	if code == t.Gen(token, ts) || code == t.Gen(token, ts-t.Step) || code == t.Gen(token, ts+t.Step) {
+		return true
+	}
+	return false
+}

totp_test.go

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+// Time-based One-time Password
+package totp
+
+import (
+	"testing"
+	"time"
+)
+
+func TestTOTP(t *testing.T) {
+	tt := TOTP{Step: RelayTOTPStep}
+	for i := 0; i < 20; i++ {
+		ts := time.Now().Unix()
+		code := tt.Gen(13666999958022769123, ts)
+		t.Log(code)
+		if !tt.Verify(code, 13666999958022769123, ts) {
+			t.Error("TOTP error")
+		}
+		if !tt.Verify(code, 13666999958022769123, ts-10) {
+			t.Error("TOTP error")
+		}
+		if !tt.Verify(code, 13666999958022769123, ts+10) {
+			t.Error("TOTP error")
+		}
+		if tt.Verify(code, 13666999958022769123, ts+60) {
+			t.Error("TOTP error")
+		}
+		if tt.Verify(code, 13666999958022769124, ts+1) {
+			t.Error("TOTP error")
+		}
+		if tt.Verify(code, 13666999958022769125, ts+1) {
+			t.Error("TOTP error")
+		}
+		time.Sleep(time.Second)
+		t.Log("round", i, " ", ts, " test ok")
+	}
+
+}