Threat Timeline: Tracking Progress Toward Q-Day

Every quantum breakthrough, every PQC milestone, every shift in the countdown to cryptographically relevant quantum computers.

Why This Matters

Q-Day isn’t a fixed date—it’s a moving target influenced by quantum hardware progress, error correction breakthroughs, and algorithmic improvements. We track both sides of this race: quantum capability advancing and cryptocurrency defenses strengthening. In May 2025, Google researcher Craig Gidney demonstrated that breaking RSA-2048 now requires fewer than 1 million qubits—a 95% reduction from 2019 estimates. The window is closing faster than anticipated.

Current State of the Race

The gap between quantum computing capability and cryptographic vulnerability is narrowing. Here’s where we stand as of late 2025:

Metric Current Status CRQC Threshold
Physical Qubits (Leading Systems) 1,000–1,400 <1 million needed
Logical Qubits Demonstrated ~12–50 ~1,400 needed for RSA-2048
Best Two-Qubit Gate Fidelity 99.9% 99.99%+ for fault tolerance
Cryptocurrencies with Mainnet PQC 1 (QRL) Majority of market cap
Consensus Q-Day Estimate 2030–2035

Translation: We’re at roughly 1–4% of the logical qubits needed to break cryptocurrency cryptography. At current progress rates, industry roadmaps project fault-tolerant quantum computers by 2029–2030. Meanwhile, only 1 of 49 tracked cryptocurrencies have strong quantum resistance.

Major Milestones: 2019–2025

The quantum computing landscape has transformed dramatically in recent years. These milestones mark the acceleration toward cryptographically relevant quantum computers:

Date Milestone
Oct 2019 Google Claims Quantum Supremacy: 53-qubit Sycamore processor completes a specific calculation in 200 seconds that would take classical supercomputers ~10,000 years. First demonstration that quantum computers can outperform classical systems on certain tasks.
Jul 2022 NIST Selects Post-Quantum Standards: After 6 years of global competition, NIST announces winners: Kyber (key encapsulation), Dilithium, SPHINCS+, and FALCON (digital signatures). Cryptocurrency projects now have proven algorithms to adopt.
Aug 2024 NIST Publishes Final PQC Standards: FIPS 203 (ML-KEM), FIPS 204 (ML-DSA), and FIPS 205 (SLH-DSA) officially released. Organizations can implement with confidence. White House mandates federal migration to PQC by 2035.
Dec 2024 Google Willow Achieves Below-Threshold Errors: 105-qubit chip demonstrates exponential error reduction as qubits scale—a critical milestone proving fault-tolerant quantum computing is achievable. Completes benchmark in 5 minutes that would take classical supercomputers 10 septillion years.
Feb 2025 Microsoft Unveils Majorana 1: World’s first topological qubit chip using novel “topoconductor” materials. Claims architecture can scale to 1 million qubits on a single chip. Approach offers inherent error resistance at hardware level.
May 2025 Gidney Paper Slashes CRQC Requirements: Google researcher Craig Gidney publishes analysis showing RSA-2048 can be broken with <1 million noisy qubits in under a week—a 95% reduction from 2019’s 20 million qubit estimate. Game-changing for timeline projections.
Jun 2025 IBM & IonQ Release Aggressive Roadmaps: IBM targets 200 logical qubits by 2029 (Starling) and 1,000+ by early 2030s (Blue Jay). IonQ projects 1,600 logical qubits by 2028 and 80,000 by 2030—potentially exceeding CRQC thresholds.
Nov 2025 IBM Nighthawk & Loon Unveiled: Nighthawk processor (120 qubits) designed for quantum advantage by 2026. Loon experimental processor demonstrates all hardware components needed for fault-tolerant quantum computing. Real-time error decoding achieved.

The “Harvest Now, Decrypt Later” Threat

One of the most insidious aspects of the quantum threat is already active. Nation-state actors and sophisticated adversaries are collecting encrypted data today with the intention of decrypting it once CRQCs become available.

Why This Matters for Cryptocurrency

Every blockchain transaction ever made is permanently recorded. Public keys exposed through transactions are stored forever. When quantum computers arrive, attackers won’t need to intercept new communications—they can simply scan historical blockchain data for vulnerable addresses with exposed keys and significant balances.

At-risk exposure: Approximately 25% of Bitcoin supply (~6.65 million addresses) and over 65% of Ethereum have exposed public keys that would be vulnerable to a future quantum attack.

This threat model means that the effective deadline for quantum-safe migration is not Q-Day itself—it’s today. Data encrypted or signed with vulnerable algorithms now will be compromised later, regardless of when protection is added.

Learn more about the Harvest Now, Decrypt Later threat →

What We’re Watching

The timeline to Q-Day depends on several factors that could accelerate or delay arrival:

Accelerators

  • Error correction breakthroughs: Reducing physical-to-logical qubit ratios
  • Algorithmic improvements: Gidney’s 2025 paper cut requirements by 95%
  • Massive investment: $3.77B raised in Q1–Q3 2025 alone
  • Government programs: US, China, EU quantum initiatives
  • New qubit architectures: Topological, photonic, neutral atom approaches

Decelerators

  • Physical limits: Decoherence and noise challenges
  • Engineering complexity: Scaling beyond 1,000 qubits
  • Talent shortage: 3 positions per qualified candidate
  • Control system latency: Real-time error correction demands
  • Cooling requirements: Near absolute zero operation

The Asymmetry Problem

Quantum computing progress is exponential (qubit counts and quality improving rapidly). Cryptocurrency migration is linear at best (5–7 years from proposal to full deployment, with governance bottlenecks). Even if Q-Day estimates slip by 2–3 years, that doesn’t help projects that haven’t started migrating. Research suggests Bitcoin’s full migration could require at least 76 days of dedicated on-chain effort in an optimistic scenario—far longer in practice.

Expert & Industry Predictions

Q-Day estimates vary widely, but the range is narrowing as hardware matures:

Source Q-Day Estimate Basis
Global Risk Institute (2024) 17–34% chance by 2034 Annual expert survey
IBM Roadmap (2025) Fault-tolerant by 2029 Starling: 200 logical qubits
IonQ Roadmap (2025) CRQC-capable by 2028 1,600 logical qubits projected
Google Quantum AI Breaking RSA: 10+ years Requires millions of physical qubits
PostQuantum.com Analysis (2025) RSA-2048 broken by 2030 Based on Gidney paper + roadmaps
NIST / White House Migration complete by 2035 Federal mandate deadline
QRC Assessment 2030–2035 Consensus of industry projections

Key insight: Even optimistic (late) estimates give cryptocurrency only 10–15 years. Given that migration takes 5–7 years and requires governance consensus, there’s little margin for error. Projects not actively preparing are already behind.

Key Indicators to Monitor

These metrics define the gap between current quantum capability and cryptographic threat:

Metric Current (2025) Danger Threshold
Logical qubits ~12–50 ~1,400 (CRQC achieved)
Error rate 0.001 (improving) 0.00000001 (needed for reliability)
Gate fidelity 99–99.9% 99.99%+ (fault tolerance)
Physical-to-logical qubit ratio ~1,000:1 <100:1 (efficient scaling)
Crypto projects with mainnet PQC 1 (QRL) Majority of market cap secured

Cryptocurrency Readiness Snapshot

While quantum hardware advances rapidly, cryptocurrency defenses lag significantly behind:

36

Critical Vulnerability (RED)

12

Upgrade Recommended (YELLOW)

1

Quantum-Ready (GREEN)

The vast majority of cryptocurrency value remains protected only by quantum-vulnerable ECDSA signatures. As of late 2025, no major cryptocurrency (Bitcoin, Ethereum, Solana, Cardano) has deployed post-quantum cryptography on mainnet. Bitcoin has no concrete BIP for PQC adoption. Ethereum’s EIP-7932 remains in discussion. The race between quantum capability and crypto defense is decisively favoring quantum.

Explore the Details

Quantum Hardware Progress

Track qubit counts, error rates, and major announcements from IBM, Google, IonQ, Microsoft and other quantum computing leaders.

See hardware timeline →

QKD vs PQC Explained

Quantum Key Distribution is often confused with Post-Quantum Cryptography. Learn why QKD is not the solution for blockchain security.

QKD vs PQC →

Q-Day Countdown Tool

Model your own Q-Day timeline by adjusting variables like hardware progress rate, error correction advances, and algorithmic improvements.

Interactive countdown →

Project Readiness Tracker

See which cryptocurrency projects are actively preparing for post-quantum migration and their current implementation status.

Readiness tracker →

Update Policy

Monthly

Regular timeline review

48 Hours

Major breakthrough response

Sourced

All data citations documented

This page is updated monthly and whenever significant milestones occur—major hardware announcements, algorithmic breakthroughs, or cryptocurrency PQC deployments. All data points are sourced from peer-reviewed research, official company announcements, and verified industry reports. If you identify an error or have updated information, please contact us with documentation.

Check Your Holdings

See how 49 cryptocurrencies score on quantum resistance using our 7-dimension methodology.

Last updated: December 4, 2025 | QRC Scoring Engine V5.1 | Next review: January 2026