import base64
import hashlib
import hmac
import struct
import time
def generate_totp(secret_base32: str, timestamp: int = None, step: int = 30, digits: int = 6) -> str:
"""
基於 RFC 6238 標準生成 TOTP 動態驗證碼
:param secret_base32: Base32 編碼的共享密鑰 (例如 ‘JBSWY3DPEHPK3PXP’)
:param timestamp: Unix 時間戳(秒)，默認使用當前時間
:param step: 時間步長，默認 30 秒
:param digits: 輸出位數，默認 6 位
:return: 補零對齊的字符串 (例如 ‘045812’)
"""
if timestamp is None:
timestamp = int(time.time())
1. 規範化 Base32 密鑰並補齊填充符 ’=’
normalized_secret = secret_base32.replace(” ”, "").upper()
padding_needed = (8 - len(normalized_secret) % 8) % 8
normalized_secret += ”=” * padding_needed
key_bytes = base64.b32decode(normalized_secret)
2. 計算 64 位大端序的時間計數器 T
time_counter = timestamp // step
time_bytes = struct.pack(“>Q”, time_counter)  # 8 字節大端整數
3. 計算 HMAC-SHA1 哈希 (返回 20 字節)
hmac_hash = hmac.new(key_bytes, time_bytes, hashlib.sha1).digest()
4. 動態截斷 Dynamic Truncation
offset = hmac_hash[-1] & 0x0F  # 取最後一個字節的低 4 位
提取連續 4 字節並清除最高有效位 (MSB)
binary_code = struct.unpack(“>I”, hmac_hash[offset : offset + 4])[0] & 0x7FFFFFFF
5. 模數運算並左補零
otp_code = binary_code % (10 ** digits)
return str(otp_code).zfill(digits)
if name == “main”:
使用測試密鑰運行
secret = “JBSWY3DPEHPK3PXP”
current_code = generate_totp(secret)
print(f”當前 30 秒有效 TOTP: {current_code}”)

const crypto = require('crypto');
// 純 JS 實現 RFC 4648 Base32 解碼
function base32Decode(base32Str) {
const alphabet = ‘ABCDEFGHIJKLMNOPQRSTUVWXYZ234567’;
const cleaned = base32Str.replace(/=+$/, ”).toUpperCase().replace(/\s+/g, ”);
let bits = 0, value = 0, index = 0;
const output = new Uint8Array(Math.floor((cleaned.length * 5) / 8));
for (let i = 0; i < cleaned.length; i++) {
const val = alphabet.indexOf(cleaned[i]);
if (val === -1) continue;
value = (value << 5) | val;
bits += 5;
if (bits >= 8) {
output[index++] = (value >>> (bits - 8)) & 255;
bits -= 8;
}
}
return Buffer.from(output.buffer, 0, index);
}
function generateTOTP(secretBase32, timestamp = Math.floor(Date.now() / 1000), step = 30, digits = 6) {
const key = base32Decode(secretBase32);
const counter = Math.floor(timestamp / step);
// 8 字節大端序寫入
const buffer = Buffer.alloc(8);
buffer.writeBigUInt64BE(BigInt(counter), 0);
// 計算 HMAC-SHA1
const hmac = crypto.createHmac(‘sha1’, key).update(buffer).digest();
// 動態截斷
const offset = hmac[hmac.length - 1] & 0x0f;
const binary = ((hmac[offset] & 0x7f) << 24) |
((hmac[offset + 1] & 0xff) << 16) |
((hmac[offset + 2] & 0xff) << 8) |
(hmac[offset + 3] & 0xff);
const otp = binary % (10 ** digits);
return otp.toString().padStart(digits, ‘0’);
}
console.log(“Node.js 生成動態碼:”, generateTOTP(“JBSWY3DPEHPK3PXP”));

package main
import (
“crypto/hmac”
“crypto/sha1”
“encoding/base32”
“encoding/binary”
“fmt”
“math”
“strings”
“time”
)
// GenerateTOTP 生成 RFC 6238 TOTP 驗證碼
func GenerateTOTP(secretBase32 string, timestamp int64, step int64, digits int) (string, error) {
// 1. 標準化 Base32 字符串並解碼
cleaned := strings.ToUpper(strings.ReplaceAll(secretBase32, ” ”, ""))
key, err := base32.StdEncoding.WithPadding(base32.NoPadding).DecodeString(cleaned)
if err != nil {
// 若缺少填充，嘗試標準解碼
key, err = base32.StdEncoding.DecodeString(cleaned)
if err != nil {
return "", err
}
}
// 2. 時間步長計數
counter := uint64(timestamp / step)
buf := make([]byte, 8)
binary.BigEndian.PutUint64(buf, counter)
// 3. HMAC-SHA1 計算
mac := hmac.New(sha1.New, key)
mac.Write(buf)
hash := mac.Sum(nil)
// 4. 動態截斷
offset := hash[len(hash)-1] & 0x0f
binaryCode := binary.BigEndian.Uint32(hash[offset:offset+4]) & 0x7fffffff
// 5. 取模格式化
mod := uint32(math.Pow10(digits))
otp := binaryCode % mod
return fmt.Sprintf(fmt.Sprintf(“%%0%dd”, digits), otp), nil
}
func main() {
code, err := GenerateTOTP(“JBSWY3DPEHPK3PXP”, time.Now().Unix(), 30, 6)
if err != nil {
panic(err)
}
fmt.Printf(“Golang 計算 TOTP: %s\n”, code)
}