IBM researchers are collaborating with Signal and Threema to develop messaging systems that can withstand the potential threats posed by quantum computing. This initiative comes in response to growing concerns that advances in quantum technology could compromise the encryption that secures communications for governments, journalists, and millions of users globally.
In a recent report, IBM highlighted the urgency of redesigning messaging protocols to prepare for a future where quantum computers might break existing encryption methods. The researchers noted, “Breaking through this kind of encryption is practically impossible with even the most capable classical supercomputers, unless you have a spare billion years to kill. But a major computing revolution underway today may soon change that.”
While much attention has been given to the quantum threat to cryptocurrencies like Bitcoin, cryptography expert Ethan Heilman suggests that encrypted messaging platforms may face a more immediate risk. “The short-term threat is much greater for something like Signal than for Bitcoin because of store-and-forward attacks,” Heilman explained. This type of attack involves intercepting and saving encrypted messages today, with the intention of decrypting them later when quantum computing capabilities advance.
Signal and Threema, both pioneers in end-to-end encrypted messaging, have taken proactive steps to bolster their security. Their systems store encryption keys on users’ devices rather than on company servers, making it more challenging for adversaries to access sensitive information. However, the potential of a powerful quantum computer to solve the cryptographic problems that underpin this security remains a pressing concern.
Recent advancements in quantum computing, demonstrated by institutions like IBM, Google, and Caltech, have improved stability and error correction, thereby accelerating the timeline for practical quantum machines. This intensifies the scrutiny on cryptocurrencies, which rely on elliptic-curve cryptography for transaction security. A sufficiently advanced quantum computer could theoretically employ Shor’s algorithm to derive private keys from public keys, posing a significant risk.
Heilman pointed out that the increasing reliance on encrypted messaging within government circles underscores the importance of long-term communication security. He referenced the 2025 incident known as “Signalgate,” where senior U.S. officials used disappearing Signal messages on personal devices to discuss sensitive matters, highlighting the potential vulnerabilities in current systems.
Future proofing
In anticipation of future threats, Signal has begun implementing measures to counteract potential “harvest now, decrypt later” attacks. In 2023, the company introduced the PQXDH upgrade to safeguard new messaging sessions, followed by the Sparse Post-Quantum Ratchet (SPQR) protocol upgrade in 2025, which extends post-quantum protection to ongoing communications.
Threema is also taking significant steps by collaborating with IBM’s cryptography researchers to integrate the National Institute of Standards and Technology-standardized ML-KEM algorithm into its messaging framework, aiming for quantum-safe encryption. Their research also emphasizes the need to protect metadata, including details about participants in encrypted group chats.
During their efforts to adapt the existing Signal protocol for quantum safety, researchers discovered that simply replacing current components with quantum-safe alternatives could lead to a substantial increase in bandwidth requirements. This realization prompted a complete redesign of the protocols to enhance speed and communication efficiency.
While experts agree that the technology capable of attacking Bitcoin remains beyond current capabilities, Heilman cautioned that the pace of development in quantum computing could accelerate as the threat becomes more tangible. “As soon as the threat becomes more real, things move quicker,” he remarked, emphasizing the need for ongoing vigilance in the face of evolving technological landscapes.
