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Attack Probability Calculator

Comprehensive cryptographic attack analysis. Brute force, birthday attacks, side-channel risks, password strength, and key derivation security.

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How to Use This Calculator
  1. Choose an Attack Type: Brute Force Analysis, Birthday/Collision Attack, Side-Channel Risk, Password Attack, or Key Derivation Security.
  2. For Brute Force Analysis, enter the key space in bits, attacker hash rate, parallel devices, and target success probability.
  3. For Birthday/Collision Attack, enter the hash output size in bits, desired collision probability, and items generated.
  4. For Side-Channel Risk, select the implementation type, attacker access level, and measurement precision to see timing, power, cache, and EM radiation risk.
  5. For Password Attack, enter password length, character set size, known patterns, and bcrypt hashing cost.
  6. For Key Derivation Security, select the KDF algorithm and enter iterations/cost, memory, and parallelism to check OWASP compliance.
  7. Review the calculated outputs -- such as time to crack, feasibility, collision probability, overall risk, strength rating, or OWASP compliance -- depending on the selected mode.

What each input means

Attack Type
Calculation mode to use.
Key Space (bits)
AES-128 = 128 bits
Attack Rate (hashes/sec)
1e12 = 1 trillion/sec
Hash Output (bits)
MD5=128, SHA-256=256
Items Generated
How many hashes created
Password Length
Desired password length.
Character Set Size
95 = printable ASCII
Hashing Cost (bcrypt)
bcrypt cost factor (10-14)
Iterations/Cost
PBKDF2: 100000+, bcrypt: 12, Argon2: 3
Memory (MB)
For scrypt/Argon2
Parallelism
For Argon2

How this is calculated

Formula

Time = KeySpace / AttackRate | Birthday = √(π/2 × N)

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Attack Type = 0, Key Space (bits) = 128, Attack Rate (hashes/sec) = 1000000000000, Parallel Devices = 1 = 19 input(s) provided
  2. Calculate Time to Crack
    Time to Crack
    5391448762278159000 = 5391448762278159000
  3. Calculate Feasibility
    Feasibility
    Beyond current technology = Beyond current technology
  4. Calculate Total Key Space
    Total Key Space
    3.402823669209385e+38 = 3.402823669209385e+38
  5. Calculate Energy Cost
    Energy Cost
    4.726143985013035e+21 = $4,726,143,985,013,035,000,000

Engine last updated . Checked against 6 independently-derived tests — how we verify calculators.

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