Shor algorithm will instantly break all encryption

01

Why people believe this

Shor's algorithm factors large numbers exponentially faster than classical computers. RSA encryption relies on factoring being hard. Therefore all encryption is immediately broken once quantum computers exist.

02

The correction

Shor's algorithm requires millions of fault-tolerant logical qubits to break RSA-2048. Gidney and Ekera (2021) estimated breaking RSA-2048 requires approximately 20 million physical qubits running for 8 hours. Current best hardware has around 1000 physical qubits with much higher error rates than needed. Additionally, post-quantum cryptography standards were finalized by NIST in 2024 — CRYSTALS-Kyber and CRYSTALS-Dilithium — and deployment has already begun.

03

Visual demonstration

Physical qubits needed to break RSA (Gidney and Ekera, 2021)

RSA-512

1,500 logical3M

RSA-1024

3,000 logical6M

RSA-2048

4,000 logical20M

RSA-4096

8,000 logical40M

Current best hardware~127 qubits

barely visible on this scale

Breaking RSA-2048 requires ~20 million physical qubits running for 8 hours. Current best hardware has 127. The gap is not closing fast enough to be a near-term threat — but post-quantum cryptography standards are already being deployed.

Loading chart...

04

Simulator note

This concept requires either mathematical proof or hardware-scale experiments beyond what a browser simulator can demonstrate. See the research notes for the canonical references.

05

Research notes