# Forward Secrecy for Asynchronous Messages

DevFeed: [Forward Secrecy for Asynchronous Messages](<https://devfeed.tech/articles/forward-secrecy-for-asynchronous-messages-1735.md>)

Original publisher: [Read original article](<https://signal.org/blog/asynchronous-security/>)

Published: 2013-08-22T00:00:00Z

Content type: article

Language: en

Sources: [Signal Blog](<https://devfeed.tech/sources/signal-blog.md>)

Topics: [Encryption](<https://devfeed.tech/topics/encryption.md>), [Messaging](<https://devfeed.tech/topics/messaging.md>), [Security](<https://devfeed.tech/topics/security.md>), [push-notification](<https://devfeed.tech/topics/push-notification.md>), [iOS](<https://devfeed.tech/topics/ios.md>), [systems](<https://devfeed.tech/topics/systems.md>)

Tags: [cryptographic](<https://devfeed.tech/tags/cryptographic.md>), [ios](<https://devfeed.tech/tags/ios.md>), [messaging](<https://devfeed.tech/tags/messaging.md>), [mobile](<https://devfeed.tech/tags/mobile.md>), [network](<https://devfeed.tech/tags/network.md>), [os](<https://devfeed.tech/tags/os.md>), [process](<https://devfeed.tech/tags/process.md>), [push-notification](<https://devfeed.tech/tags/push-notification.md>), [security](<https://devfeed.tech/tags/security.md>)

## AI overview

The article explains how traditional asynchronous messaging uses a recipient's static public key, allowing recorded ciphertext to be decrypted if that key is later compromised. It describes how OTR uses ephemeral Diffie-Hellman exchanges and continually ratchets key material to provide Perfect Forward Secrecy. It then examines why OTR must be adapted for asynchronous mobile messaging, including iOS background delivery through Apple Push Notifications.

## Source excerpt

Traditionally, asynchronous messaging systems such as email have relied on protocols like PGP or S/MIME for cryptographic security. These protocols work the way most people are familiar with: one who wishes to receive encrypted email advertises a public key, and those wishing to send encrypted email to that person encrypt their outgoing message with that public key. Read more...