Cannot encrypt to a local key using Mobile Encryption for iOS

Products

• Mobile Encryption for iOS

Issue/Introduction

Mobile Encryption for iOS can store user keys in its local keyring. This avoids the app having to lookup keys on Encryption Management Server.

To import a user key, send the key as a *.asc email attachment, tap on the attachment and choose Copy to Mail Encrypt to import it to the local keyring.

To encrypt to a local key, follow the same procedure as when encrypting to a key stored in Encryption Management Server:

1. Open Mobile Encryption for iOS and tap on New Message.
2. Enter the recipient's email address in the To field.

If the recipient's email address is displayed as follows, a suitable key can be found:
[email protected]

If the recipient's email address is displayed as follows, a suitable key cannot be found:
? [email protected] 

After importing a local key, you find that Mobile Encryption for iOS cannot find it.

Environment

Mobile Encryption for iOS 2.0 and above with local keys.
 

Cause

Mobile Encryption for iOS can only encrypt to local keys that have been signed with an exportable signature.

Resolution

To sign the key with an exportable signature, you will need to use Encryption Desktop:

1. Open Encryption Desktop using the same account that is enrolled with Mobile Encryption for iOS.
2. Import the key by opening the *.asc file.
3. Right click on the imported key and choose Sign.
4. Check the option Allow signature to be exported which is unchecked by default.
5. The key will show as Verified and you will be able to use it to encrypt mail using Encryption Desktop.

To use the key in Mobile Encryption for iOS:

1. Export the signed key to a *.asc file.
2. Email the *.asc file to yourself and open the message with the *.asc attachment in Mobile Encryption for iOS.
3. Tap on the *.asc attachment and choose Copy to Mail Encrypt to import it to the local keyring.