Encryption Key Strength Calculator
Evaluate the strength of encryption keys based on algorithm type, key length, and attacker capability. Estimates security bits and time-to-crack using standard cryptographic models.
Formulas Used
Symmetric (AES / ChaCha20):
Security bits = n (key length). Brute-force requires 2n operations.
With Grover's quantum algorithm: Security bits = n / 2.
RSA / Diffie-Hellman:
Security bits ≈ log₂(exp(1.923 · (ln n)1/3 · (ln ln n)2/3))
Based on General Number Field Sieve (GNFS) sub-exponential complexity L[n, 1/3, 1.923].
With Shor's quantum algorithm: Security bits = 0 (broken in polynomial time).
Elliptic Curve (ECC):
Security bits = n / 2 (Pollard's rho attack on ECDLP: O(2n/2) operations).
With Shor's quantum algorithm: Security bits = 0 (broken in polynomial time).
Hash / HMAC Key:
Security bits = n (preimage resistance). With Grover: Security bits = n / 2.
Time to Crack:
T = 2security_bits / attacker_ops_per_second (seconds)
Assumptions & References
- Brute-force assumes an exhaustive key search with no algorithmic shortcuts beyond those modeled (GNFS for RSA, Pollard's rho for ECC).
- Attacker speeds are order-of-magnitude estimates; real-world performance varies by implementation and hardware generation.
- Quantum attack estimates assume a cryptographically relevant quantum computer (CRQC) with sufficient logical qubits — not yet available as of 2024.
- Security bit thresholds follow NIST SP 800-57 Part 1 Rev 5 (2020), Table 2: 80-bit (legacy), 112-bit (2030), 128-bit (post-2030).
- RSA/DH security-bit formula: Lenstra & Verheul (2001) and NIST SP 800-57 Table 2 mapping.
- ECC security bits = n/2 per NIST SP 800-57 and ECRYPT-CSA D5.4 (2018).
- Grover's algorithm reference: Grover, L.K. (1996), STOC '96.
- Shor's algorithm reference: Shor, P.W. (1994), FOCS '94.
- Post-quantum migration guidance: NIST FIPS 203/204/205 (2024) — CRYSTALS-Kyber, CRYSTALS-Dilithium, SPHINCS+.
- This calculator models key strength only. Real-world security also depends on protocol design, implementation quality, key management, and side-channel resistance.