# Advanced cryptographic ratcheting

DevFeed: [Advanced cryptographic ratcheting](<https://devfeed.tech/articles/advanced-cryptographic-ratcheting-1728.md>)

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

Published: 2013-11-26T00:00:00Z

Content type: article

Language: en

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

Topics: [Ratchet](<https://devfeed.tech/topics/ratchet.md>), [Security](<https://devfeed.tech/topics/security.md>), [Encryption](<https://devfeed.tech/topics/encryption.md>), [Messaging](<https://devfeed.tech/topics/messaging.md>), [Protocol (disambiguation)](<https://devfeed.tech/topics/protocol.md>)

Tags: [cryptographic](<https://devfeed.tech/tags/cryptographic.md>), [messaging](<https://devfeed.tech/tags/messaging.md>), [open](<https://devfeed.tech/tags/open.md>), [security](<https://devfeed.tech/tags/security.md>)

## AI overview

The article describes improvements to TextSecure's encrypted asynchronous chat protocol, including a key exchange mechanism for asynchronous transports and an enhanced OTR forward-secrecy ratchet. It explains how ephemeral Diffie-Hellman keys are advertised, acknowledged, and advanced during a session to protect recorded ciphertext if a later key compromise occurs.

## Source excerpt

At Open Whisper Systems, we've been working on improving our encrypted asynchronous chat protocol for TextSecure. The TextSecure protocol was originally a derivative of OTR, with minor changes to accommodate it for transports with constraints like SMS or Push. Some of the recent changes we've made include simplifying and improving OTR's deniability, as well as creating a key exchange mechanism for asynchronous transports. Our most recent change incorporates what we believe to be substantial improvements to OTR's forward secrecy "ratchet." Read more...