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Encryption Key Space Calculator

Calculate encryption key space size, brute force time, and security level for cryptographic algorithms.

Inputs

bits

Results

Key Space Size

3.4 × 10³⁸

Key Space (bits)

128 bits

Security Level

128 bits

Brute Force Time

5.4 × 10¹⁸

vs DES Key Space4.7 × 10²¹
How to Use This Calculator
  1. Enter the encryption key length in bits.
  2. Set the attacker compute speed in operations per second.
  3. Review the total number of possible keys and brute-force time in years.
  4. Verify key length meets NIST minimum recommendations: 128-bit AES or 2048-bit RSA.
  5. Use the output to justify key length choices in security architecture documentation.

What each input means

Key Length
Encryption key length in bits
Algorithm
Encryption algorithm

How this is calculated

Formula

Key Space = 2^keyLength

Worked example, using the default values

  1. Identify Input Parameters
    Key Length = 128, Algorithm = 0 = 2 input(s) provided
  2. Calculate Key Space Size
    Key Space Size = formatSuperscript(actualKeySpace)
    3.4 × 10³⁸ = 3.4 × 10³⁸
  3. Calculate Key Space
    Key Space = Math
    128 = 128
  4. Calculate Security Level
    128 = 128
  5. Calculate vs DES Key Space
    vs DES Key Space = formatSuperscript(keySpaceMultiplier)
    4.7 × 10²¹ = 4.7 × 10²¹

Engine last updated . Checked against 1 independently-derived test — how we verify calculators.

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