On January 25, a16z Crypto released a detailed article titled “Quantum Computing and Blockchain: Aligning Immediacy with Realistic Threats,” noting that views on quantum computing’s threat are sharply polarized — both overoptimism and overworry are misplaced. Currently, publicly documented quantum computing advances are nowhere near enabling practical use of the Shor algorithm to crack RSA/ECDSA encryption, but long-term risks can’t be fully dismissed. Quantum computing presents vastly different threat timeframes for different cryptographic primitives. Encryption could be vulnerable to “Harvest Now, Decrypt Later” (HNDL) attacks, requiring an early shift to post-quantum encryption. Signatures, by contrast, aren’t easily targeted by HNDL attacks. Rushing to adopt post-quantum signatures, however, may cause performance hits, immature implementations, and new risks like code bugs — calling for a cautious transition plan.
