startssl的免費ssl證書有一年的有效期（包括登錄startssl的用戶登錄證書和域名ssl證書）。上年申請的StartSSL的免費SSL證書快要過期了，需要renew。StartSSL證書的續期步驟和新申請證書的步驟差不多。請閱讀本文并參考《全球唯一免費HTTPS證書頒發機構：StartSSL申請圖文詳細教程》

續期步驟為：
1）更新用戶登錄證書
2）更新域名ssl證書

在用戶證書過期前兩星期注冊郵箱會收到類似提示郵件：

This mail is intended for the person who owns a digital certificate issued by the StartSSL Certification Authority (http://www.startssl.com/).
 The Class 1, client certificate for xxx@xxx.com and serial number xxxxxx (xxxxx) is about to expire in about two weeks. Please log into the StartSSL Control Panel at https://www.startssl.com/?app=12 and get a new certificate for this purpose. Failing to update your client certificate might result in the loss of your account.
 Should you have lost the client certificate which was previously issued to you, please register once again - login without the client certificate installed into your browser will not work in that case.

瀏覽器訪問https://www.startssl.com/?app=12，如果用戶證書已過期只能重新注冊一個帳號了。

1、導入之前注冊時得到的p12證書，然后登陸到Control Panel:
Validations Wizard -> Type: Domain Name validation -> Enter Domain Name -> Select Verification Email -> 輸入Email收到的Verification code -> finish;

2、Certificates Wizard -> Certificate Target: Web Server SSL/TLS Certificate -> 輸入密碼或跳過 -> 保存好key -> 選擇需要部署SSL的域名 -> 等待審核;

3、(收到Email審核成功的通知后) Tool Box -> Retrieve Certificate -> 選擇剛申請的域名, Continue -> 保存好Certificate.

至此，得到新的SSL證書。過期時間是2013-05-10，如下圖。

問題是，登陸StartSSL控制面板不是通過帳號密碼，而是使用個人證書來驗證的。如上圖紅圈處，這個人證書過期時間并無更新，仍然是2012年5月22日。所以，我們不但要renew站點的SSL證書，還要renew這個用于登陸StartSSL的證書。否則，明年（準確來說是十幾天后）就無法登陸StartSSL了。(只能重新注冊)

renew這個個人證書，只需重新驗證EMail:

1、 Validations wizard -> Type: Email Address Validation -> Enter Email Address -> 輸入Email收到的Verification code -> finish;

2、 Certificates wizard -> Certificate Target: S/MIME and Authentication Certificate -> Generate Private Key -> Select Email Address -> Your S/MIME client certificate is installed in your browser;

3、 Tool Box -> Retrieve Certificate -> 選擇新申請的Email, Continue.

至此，得到新的p12個人證書。過期時間2013年5月10日。

然后再備份好這個新的p12個人證書，以備后用。