A key whose value is a string to match against a certificate or identity's email address.
- iOS 2.0+
- macOS 10.6+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
The corresponding value is of type
CFString and contains an RFC822 email address. If provided, returned certificates or identities are limited to those that either contain the address or do not contain any email address.