SHANNON INFORMATION THEORY AUDITOR

Password Entropy & GPU Crack Time Auditor

Evaluate the mathematical strength of passwords using Shannon Entropy ($E = L \times \log_2 R$). 100% private: all calculations execute in your browser's local memory; zero passwords ever touch a network.

Enter Password or Passphrase to Audit

SECURITY TIER:

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Shannon Entropy

0 bits

Target > 65 bits for modern security

Character Pool Size (R)

0 characters

Letters, numbers, special symbols

Total Password Length

Character count

Brute-Force Cracking Time Estimates (Offline Hardware)

Attack Scenario	Hash Rate Capacity	Estimated Time to Crack
Online Attack (Web Login)	100 guesses / second (rate-limited)	-
GPU Rig (Nvidia RTX 4090 Hashcat)	100 Billion guesses / second ($10^{11}$)	-
State Supercomputer / Distributed Botnet	100 Trillion guesses / second ($10^{14}$)	-

The Mathematical Definition of Password Entropy

Password entropy is a measurement of unpredictability borrowed from Claude Shannon's Information Theory. It calculates the logarithm of all possible combinations given the length of the string ($L$) and the character pool size ($R$):

Entropy (Bits) = Length × log₂(Pool Size)

Every bit of entropy doubles the time required for a brute-force attacker to guess the credential. For instance, an 8-character lowercase password provides approximately 37.6 bits of entropy, which modern GPU clusters can exhaust in less than 2 minutes. In contrast, a 20-character passphrase generates over 90 bits of entropy, requiring billions of years to compute.