Researchers from IBM are collaborating with encrypted messaging services Signal and Threema to redesign protocols against future quantum attacks. Cryptographer Ethan Heilman stated that messaging faces a greater near-term quantum risk than Bitcoin due to “store-and-forward” attacks, where communications can be recorded now and decrypted later. Advances in quantum computing are accelerating efforts to adopt post-quantum cryptography.
IBM researchers have detailed a collaborative effort with developers from Signal and Threema to create quantum-resistant messaging systems. “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,” the researchers wrote in a report.
Cryptography researcher Ethan Heilman explained that encrypted messaging may be more immediately vulnerable than Bitcoin. “The short‑term threat is much greater for something like Signal than for Bitcoin because of store‑and‑forward attacks,” Heilman said. This refers to adversaries intercepting and saving encrypted data to decrypt it later with a quantum computer.
Heilman highlighted the use of Signal by U.S. national security officials, referencing the 2025 incident known as “Signalgate”. “Historically, there have been intelligence cases where communications were recorded decades earlier and only broken later,” he noted. This creates a risk of future decryption that does not exist for cryptocurrency transactions.
Signal has already implemented upgrades like PQXDH and SPQR to defend against such attacks. Threema is exploring integrating the NIST-standardized ML-KEM algorithm for quantum-safe encryption. The research also focuses on protecting metadata about group chat participants without drastically increasing bandwidth.
Most researchers agree that quantum computers capable of attacking Bitcoin remain distant. However, Heilman observed that development accelerates as the threat becomes more tangible. “As soon as the threat becomes more real, things move quicker,” he stated.
