Who reads your mails? With regular mails you, the receiver, all mail providers and maybe others can read them. With end-to-end encrypted mails only the sender and the receivers can read them. Our iOS-App Letterbox makes end-to-end encryption easy to use, is compatible with most mail providers and supports the standard encryption protocol OpenPGP.

Letterbox is simlar to common mail apps but indicates the security state of incoming and outgoing mails. We disinguish between a confidential and insecure mails.

Confidential mail

• Only you and the sender know the content of the mail.
• You know which mails the sender sent before.
• Sender and receiver need Letterbox or compatible mail client.

Insecure mail

• You, the sender and all involed mail providers know the cntent of the mail.
• But who sent the mail? Sender addresses can be freely chosen.
• A fraud can impersonate a person when using a known mail address as sender address.