Post-Quantum Risk Evaluator

Learned Hand Formula Applied to HNDL and Mosca's Theorem

⚠️ The Legal Risk of Post-Quantum Delay

The Learned Hand Formula (from U.S. v. Carroll Towing Co., 1947) states that negligence occurs when B < PL, where B is the burden (cost) of prevention, P is the probability of harm, and L is the magnitude of loss. In the context of Post-Quantum Cryptography and the "Harvest Now, Decrypt Later" (HNDL) threat, this means: if the cost of implementing PQC now is less than the expected loss from quantum decryption (probability × damages), delaying PQC migration could create legal exposure.

📊 Industry Scenario:

Select an industry scenario to load typical values for that sector, or choose "Custom" to set your own parameters.

Currency:

📚 Learn More: Deep Dive into Mosca's Theorem ▼

Mosca's Theorem: Quantum Security Preparedness

Mosca's Theorem provides a framework for determining when organizations must act to protect against quantum computing threats. The inequality (X + Y) > Z helps assess quantum readiness.

Quantum Threat Probability (Mosca 2015)

"There is a 1 in 7 chance that some fundamental public-key crypto will be broken by quantum by 2026, and a 1 in 2 chance of the same by 2031." — Dr. Michele Mosca

~14%

by 2026

(1 in 7)

~50%

by 2031

(1 in 2)

~70%

by 2035

(projected)

~85%

by 2040

(projected)

⚠️ Uncertainty Note

These probabilities are estimates based on 2015 analysis and carry significant uncertainty. Quantum computing development timelines remain unpredictable. Recent advances (or setbacks) may shift these probabilities. Use these as general guidance, not precise predictions.

📌 Why X + Y Are Cumulative: The "Harvest Now, Decrypt Later" (HNDL) Threat

For HNDL-sensitive data, X and Y don't overlap because adversaries can steal encrypted data today and store it until quantum computers become available to decrypt it. Even if you start migrating to quantum-safe cryptography immediately, any HNDL-sensitive data encrypted with current algorithms during the Y-year migration period remains at risk. If your data needs to stay secret for X years, and migration takes Y years, you need X + Y years total before all at-risk data's confidentiality requirement expires.

Interactive Timeline Visualization

X: Data Security Period

Y: Migration Time

Z: Quantum Threat

⚠️ Q-Day (Z)

⟦ Z = Quantum Computer Arrival 9 years

When will quantum computers be able to break current encryption?

03691215

8 ≤ 9

What This Tool Does NOT Assess

This tool provides an educational framework for understanding post-quantum risk through Mosca's Theorem and the Learned Hand Formula. However, it has important limitations.

Factors Not Modeled:

Regulatory compliance requirements – NIST, NSA, industry-specific mandates
Industry standards and peer behavior – what competitors are doing
Insurance coverage and availability – cyber insurance requirements
Vendor readiness – supply chain and ecosystem maturity
Technical feasibility – system compatibility and migration complexity
Data classification nuances – different data types may need different timelines
Operational impacts – business continuity during migration

Recommended Next Steps:

Consult with legal counsel about your specific risk profile

Engage cybersecurity experts for technical feasibility assessment

Review regulatory requirements applicable to your industry

Conduct comprehensive data classification to identify HNDL-sensitive information

Document your decision-making process regardless of chosen timeline