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Calcimator

Encryption Strength Calculator

Estimate brute-force time from key length and attacker computing power. Covers symmetric (AES) and asymmetric (RSA) algorithms with quantum threat modeling.

Inputs

Results

Effective key strength (bits)

256

Security rating (0-4)

4

Log10 crack time (seconds)64.76
Meets NIST 2030 standard1
Time Description1.33e+47 × age of universe
Time Unituniverse ages
How to Use This Calculator
  1. Enter key length (bits) -- AES-128, AES-256, RSA-2048, RSA-4096, EC-256, or EC-384.
  2. Set attacker speed in log10 keys/sec -- GPU farm ~15, nation-state ~18.
  3. Select algorithm type (symmetric or asymmetric) and toggle quantum threat.
  4. Review effective security bits, estimated crack time (log10 seconds), security rating, and NIST 2030 compliance.
  5. Migrate RSA-2048 to RSA-4096 or EC-256 -- NIST recommends minimum 128 bits of security through 2030.

How the result changes with Key length (bits)

Key length (bits)Effective key strength (bits)Security rating (0-4)
4174174
1,4391,4394
2,6652,6654
3,6873,6874

What each input means

Key length (bits)
Cryptographic key size. AES: 128/192/256. RSA: 1024/2048/3072/4096.
Attacker speed (log10 keys/sec)
Log10 of keys tested per second. 9 = single GPU, 12 = GPU cluster, 15 = nation-state, 20 = theoretical quantum.
Algorithm type (0-1)
0 = Symmetric (AES, ChaCha20). 1 = Asymmetric (RSA, DSA) — effective strength is much lower than key length.
Quantum threat (0-1)
0 = Classical computing only. 1 = Quantum (Grover halves symmetric strength; Shor breaks RSA entirely).

What each result means

Effective key strength (bits)
Effective symmetric-equivalent key strength after algorithm and quantum adjustments.
Log10 crack time (seconds)
Logarithm (base 10) of average brute-force time in seconds. >17 ≈ beyond human lifetime.
Security rating (0-4)
0 = Broken, 1 = Weak (<80 bits), 2 = Acceptable (80-127), 3 = Strong (128-255), 4 = Overkill (256+).
Meets NIST 2030 standard
1 = Yes (≥128 effective bits), 0 = No. NIST requires 128-bit minimum security strength through 2030+.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Key length (bits) = 256, Attacker speed (log10 keys/sec) = 12, Algorithm type (0-1) = 0, Quantum threat (0-1) = 0 = 4 input(s) provided
  2. Calculate Effective key strength
    Effective key strength
    256 = 256
  3. Calculate Security rating
    Security rating
    4 = 4
  4. Calculate Log10 crack time
    Log10 crack time = log10AvgAttempts - keysPerSecondLog10
    64.76 = 64.76
  5. Calculate Meets NIST 2030 standard
    1 = 1

Engine last updated .

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