UW Digital ID (Mac) - Apple Mail - Security Header Does Not Appear
Email messages viewed in Apple Mail will sometimes not display the security header indicating they have been digitally signed.
This problem is specific to users viewing email with Apple Mail (Mac Mail). This can happen for one of the following reasons:
- The sender's signing and encryption algorithms are set to something other than SHA-1 and 3DES, respectively. Apple Mail's security header does not know what to display when emails with more stringent encryption settings are received, so the header will not be displayed at all.
- The email is not digitally signed.
How to Fix
Because the current version of Apple Mail does not allow users to configure which signing and encryption algorithms to accept, there is no simple workaround. If you are affected by this issue, the only known "fixes" are as follows:
- Contact the sender directly to verify that the email was digitally signed.
- Use a mail client other than Apple Mail to view your email.
- Ask the sender to change his or her signing and encryption settings to SHA-1 and 3DES, respectively. Senders using Microsoft Outlook can use the following document for assistance with changing these settings: UW Digital ID (Mac) - Configuring Outlook 2011 to use a UW Digital Certificate.