# Signal Protocol and Post-Quantum Ratchets

DevFeed: [Signal Protocol and Post-Quantum Ratchets](<https://devfeed.tech/articles/signal-protocol-and-post-quantum-ratchets-1846.md>)

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

Published: 2025-10-02T00:00:00Z

Content type: article

Language: en

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

Topics: [Cryptography](<https://devfeed.tech/topics/cryptography.md>)

Tags: [attacks](<https://devfeed.tech/tags/attacks.md>), [cryptographic](<https://devfeed.tech/tags/cryptographic.md>), [encryption](<https://devfeed.tech/tags/encryption.md>), [messaging](<https://devfeed.tech/tags/messaging.md>), [open-source](<https://devfeed.tech/tags/open-source.md>), [post-quantum](<https://devfeed.tech/tags/post-quantum.md>), [quantum](<https://devfeed.tech/tags/quantum.md>), [quantum-computing](<https://devfeed.tech/tags/quantum-computing.md>), [resilience](<https://devfeed.tech/tags/resilience.md>), [security](<https://devfeed.tech/tags/security.md>)

## AI overview

Signal introduces the Sparse Post Quantum Ratchet (SPQR), which is combined with the existing Double Ratchet as the Triple Ratchet to provide quantum-safe forward secrecy and post-compromise security.

## Source excerpt

We are excited to announce a significant advancement in the security of the Signal Protocol: the introduction of the Sparse Post Quantum Ratchet (SPQR). This new ratchet enhances the Signal Protocol's resilience against future quantum computing threats while maintaining our existing security guarantees of forward secrecy and post-compromise security. Read more...