US Patent 11658823 End-to-end encryption based on a simple shared secret

This invention enables asynchronous encrypted communication under a protection of a simple password which must be communicated out-of-band. The password is easily communicable in-person, by telephone or by a text message. The invention assumes that one of the parties has an online device, such as a smartphone. After the encrypted session has been established, it can be used for a variety of cryptographic applications, such as encrypting or decrypting messages, sharing of cryptographic keys, and verifying data. The invention also has the secondary benefit of authenticating both parties to each other.