編碼器、解碼器與雜湊產生器
在 Base64、URL、HTML 實體與 hex 之間來回轉換文字，並產生 MD5、SHA-1、SHA-256 及 SHA-512 雜湊。完全在您的瀏覽器中進行。
編碼、解碼或雜湊文字
工程師的日常編碼工具
編碼將文字轉換為傳輸安全的格式；雜湊則產生無法還原的固定長度指紋。當您偵錯 API、為強制入口建立重新導向 URL 或驗證檔案完整性時，這兩者都會經常派上用場。此工具完全在本地端運作，因此絕不會上傳敏感輸入。
此工具為您提供
- 支援 Base64、URL、HTML 實體與 hex 的雙向轉換，並在輸入無效時提供清晰的錯誤訊息。
- 從任何文字輸入產生 MD5、SHA-1、SHA-256 及 SHA-512 雜湊。
- 說明哪些演算法適用於安全防護，哪些僅適用於舊版總和檢查碼。
Captive portal redirect parameters and URL encoding standards
When a wireless client associates with a guest WiFi network, the access point (AP) or wireless LAN controller (WLC) intercepts the initial HTTP request and issues an HTTP 302 redirect to the external captive portal splash page. To maintain state across the onboarding flow, the controller appends essential hardware and network context to the query string.
1. Cisco Meraki splash parameters
Meraki MR access points pass base_grant_url (the endpoint to authorise the client), user_continue_url (the guest's target URL), node_mac (AP MAC address), and client_mac. Correct percent-encoding of the grant and continue URLs is essential to prevent redirection loops.
2. Aruba ClearPass and Instant AP parameters
Aruba Instant APs and controller-managed architectures pass cmd=login, mac, ip, essid, apname, and url. Nested original destination URLs must be safely decoded when constructing post-login landing pages.
3. Ruckus SmartZone and ZoneDirector parameters
Ruckus controllers forward sip (controller IP), uip (client IP), mac (unformatted or colon-separated MAC), vlan, and url. Our tool detects MAC formats and automatically identifies Ruckus controller redirect structures.
For a complete technical overview of captive portal onboarding protocols, RADIUS authentication, and walled garden configurations, review our comprehensive captive portal technical guide and the RADIUS setup reference guide.
Cryptographic hash functions and webhook signature reference table
Cryptographic hashes produce deterministic, fixed-length digest outputs from arbitrary input data. Unlike encoding (which is fully reversible), cryptographic hashes are one-way functions designed to verify data integrity and authenticate API requests.
| Algorithm | Digest Output Length | Security Status | Primary Application | Standard Specification |
|---|---|---|---|---|
| HMAC-SHA256 | 256 bits (64 hex chars) | Strong (Recommended) | API authentication, webhook signature validation (Purple Webhooks, Stripe) | RFC 2104 / FIPS 198 |
| SHA-256 | 256 bits (64 hex chars) | Strong (Recommended) | TLS certificates, digital signatures, blockchain proof-of-work | FIPS 180-4 / NIST |
| SHA-512 | 512 bits (128 hex chars) | Strong (Recommended) | High-security password hashing (with salt/KDF), data archiving | FIPS 180-4 / NIST |
| SHA-384 | 384 bits (96 hex chars) | Strong (Recommended) | NSA Suite B cryptography, enterprise VPN integrity checks | FIPS 180-4 / NIST |
| SHA-1 | 160 bits (40 hex chars) | Deprecated | Git commit hashes, legacy file integrity checks (insecure for TLS) | RFC 3174 (SHAttered attack 2017) |
| MD5 | 128 bits (32 hex chars) | Insecure / Broken | Legacy non-cryptographic file checksums and Content-MD5 headers | RFC 1321 (Collision vulnerable) |
| CRC32 | 32 bits (8 hex chars) | Non-Cryptographic | Ethernet frame check sequences (FCS), ZIP file archive integrity | IEEE 802.3 |
Understanding the differences: encoding, encryption, and hashing
Encoding (Reversible, No Key)
Transforms data into a format safe for transmission across networks or storage in text systems (e.g. Base64, URL percent-encoding). Anyone can decode encoded data without a secret key. Encoding does not provide confidentiality.
Hashing (One-Way, Deterministic)
Generates a fixed-size fingerprint from input data. It is computationally infeasible to reconstruct the original input from the hash (preimage resistance) or find two inputs with the same hash (collision resistance). Used for integrity checks.
Encryption (Reversible with Key)
Transforms plaintext into ciphertext using a mathematical cipher (e.g. AES-256, RSA) and a cryptographic secret key. Only holders of the decryption key can recover the original data. Provides confidentiality.
Automate guest WiFi onboarding and webhook data delivery
Eliminate manual captive portal scripting. Purple connects natively with Cisco Meraki, Aruba, Ruckus, Fortinet, and Extreme Networks to automate guest authentication, GDPR-compliant data capture, and real-time webhook delivery to your CRM.
Related network engineering tools and technical guides
RADIUS setup guide
Configure FreeRADIUS and Cloud RADIUS servers with Cisco, Aruba, and Ruckus controllers.
SSL certificate checker
Inspect TLS certificates, certificate chains, expiry dates, and SAN extensions for captive portal domains.
MAC address lookup
Identify OUI vendor details, device manufacturers, and randomisation status for connected clients.
Captive portal guide
Comprehensive architectural reference for guest WiFi authentication and compliance.
Frequently asked questions
編碼、加密與雜湊之間有何不同？
編碼（例如 Base64 或 URL 編碼）是一種可逆的轉換，旨在進行安全的資料傳輸；任何人無需金鑰即可進行解碼。加密是使用秘密密碼金鑰將資料轉換為密文，以確保機密性，只有獲得授權的金鑰持有者才能對其進行解密。雜湊是一種單向數學函數，可從輸入資料計算出唯一的固定長度摘要；它無法被解密，用於驗證資料的完整性。
為什麼強制入口重新導向參數需要進行 URL 編碼？
當無線區域網路控制器 (WLC) 攔截 HTTP 請求以顯示歡迎頁面時，它會將重新導向參數（例如原始 URL、MAC 位址和授權端點）附加到查詢字串中。斜線 (/)、冒號 (:) 和問號 (?) 等字元必須進行百分比編碼，以免網頁瀏覽器和代理伺服器將巢狀參數誤判為 URL 分隔符號。
Base64url 與標準 Base64 有何不同？
標準 Base64 (RFC 4648) 使用加號 (+) 和正斜線 (/)，這些符號在 URL 和檔案名稱中具有特殊的語法意義。Base64url (RFC 7515) 將加號替換為連字號 (-)，將斜線替換為底線 (_)，並去除末尾的填補等號 (=)，使權杖可以安全地用於 URL 查詢字串、HTTP 標頭和 JSON Web Tokens (JWT)。
如何驗證 API Webhook 上的 HMAC-SHA256 簽章？
當外部平台（例如 Purple、Stripe 或 GitHub）傳送 Webhook 事件時，它會使用共享金鑰透過 HMAC-SHA256 產生原始 HTTP 請求主體的雜湊值，並將其包含在簽章標頭中。您的伺服器會使用相同的金鑰計算出相同的 HMAC-SHA256 雜湊值，並使用固定時間字串比較來比對摘要，以驗證其真實性。
2026 年有哪些雜湊演算法對於網路憑證是安全的？
NIST 強烈推薦使用 SHA-256、SHA-384 和 SHA-512（SHA-2 系列）以及 SHA-3 來確保密碼學完整性和數位簽章。MD5 和 SHA-1 已被證實存在數學碰撞漏洞，絕不能用於安全目的或密碼雜湊。
此工具是否會將我的任何權杖、機密資料或 URL 傳送到外部伺服器？
否。所有編碼、解碼、JSON Web Token 解析和密碼雜湊計算均使用標準 JavaScript 和原生 HTML5 Web Crypto API (crypto.subtle) 100% 在您的瀏覽器本機執行。任何承載資料均不會傳輸至 Purple 或第三方伺服器。
Building captive portals or webhook integrations?
Encoding redirect URLs and validating HMAC webhook signatures is part of every custom WiFi deployment. Purple automates the complete onboarding workflow, data validation, and CRM synchronisation across your entire access point fleet.
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