Joe, a user, has been trying to send Ann, a different user, an encrypted document via email. Ann has not received the attachment but is able to receive the header information. Which of the following…

Unencrypted credentials would typically affect the initial sending of the email by Joe, potentially preventing the entire email from being sent or flagging it as insecure, rather than selectively blocking only the encrypted attachment upon receipt by Ann.

For Ann to receive and securely process an encrypted attachment, her mail system or client typically needs to authenticate her identity or verify her access rights, often against a key management system or directory service like Azure AD for certificate validation. If authentication issues occur during this critical identity verification process, security mechanisms on Ann's mail server or client may prevent the encrypted attachment from being delivered or displayed to her, even while allowing the non-encrypted email headers to pass through, preventing unauthorized access or decryption failures.

A weak cipher suite might cause the encrypted attachment to be flagged as insecure or rejected entirely by a security policy, but it is less likely to specifically allow headers while stripping the attachment compared to an authentication failure that prevents the necessary processing or decryption.

While permission issues can prevent Ann from opening or decrypting a file once received, 'authentication issues' represent a more fundamental problem that could prevent the encrypted attachment from even being delivered to her inbox if her identity cannot be verified to grant those permissions.