原文地址：http://www.eifr.com/article.php?id=1966
1.啓動keychainAccess.app 路徑：Application=>Utilities
2.選擇login->Certificates,選擇自己要到出的證書(如圖)
3.右鍵選擇export…會提示設置密碼，自己設個就好
4.注意機器可能會提示輸入本機管理員密碼
5. 在你需要的機器上安裝證書（.cer），導入私鑰文件(.p12)。安裝對應App的provisioning profile。
開發者證書介紹
1. Certification(證書)
證書是對電腦開發資格的認證，每個開發者帳號有一套，分爲兩種：
1) Developer Certification(開發證書)
安裝在電腦上提供權限：開發人員通過設備進行真機測試。可以生成副本供多臺電腦安裝；
2) Distribution Certification(發佈證書)
安裝在電腦上提供發佈iOS程序的權限：開發人員可以製做測試版和發佈版的程序。
2. Provisioning Profile(授權文件)
授權文件是對設備如iPod Touch、iPad、iPhone的授權，文件內記錄的是設備的UDID和程序的App Id，即使被授權的設備可以安裝或調試Bundle identifier與授權文件中記錄的App Id對應的程序。
1) Developer Provisioning Profile(開發授權文件)
2) Distribution Provisioning Profile(發佈授權文件)
（方便的方法，Windows->Organizer, LIBRARY->Provisioning Profile 點擊refresh按鈕 導入provisioning profile）
文章2
在創建開發供應配置文件的時候，如果想在多臺mac機器上共用同一個證書文件，首先就是按照下面說的：
When you request a certificate from the iPhone Provisioning Portal, a public/private key pair is generated. The public key is included in your certificate. The private key is stored in your keychain. With these items, Xcode code-signs the applications you build
with it. If you need to use another computer to develop iOS applications, you must transfer these digital-identification items to the other computer. You can do this in the Xcode Organizer.
To export your digital-identification items to a secure file, follow these steps:
Open the Xcode Organizer.
In the IPHONE DEVELOPMENT group, select Developer Profile.
Click Export Developer Profile.
Name the file, select a location for it, enter a password to secure the file, and click Save.
Now, when you need to develop iOS applications on another computer, import your digital-identification items into it by performing these steps:
Copy the developer-profile archive to the second computer.
On the second computer, launch Xcode.
Open the Organizer.
In the IPHONE DEVELOPMENT group, select Developer Profile.
Click Import Developer Profile.
Locate the archive, enter the password used to secure it, and click Open.
關鍵的一點就是不是直接從keychain裏導出.cer文件，而是利用Xcode的organizer的IPHONE DEVELOPMENT －－－》Developer Profile裏自帶的Export和Import操作，否則便會出錯。（方便的方法，點擊refresh按鈕 導入provisioning profile）
