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Category Security

PIN Length

3 – 12 digits

Number of PINs

1 – 50 PINs

Security Rules

No sequential digits (123, 876) No repeated digits (1111, 0000) No palindromes (1221, 7337) Exclude common weak PINs No year patterns (19xx, 20xx)

Quick Presets

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About

A compromised ATM PIN results in direct financial loss. The most common PINs - 1234, 0000, 1111 - account for roughly 11% of all four-digit codes in circulation. Attackers exploit this predictability. This tool generates PINs using the browser's Cryptographic Random Number Generator (crypto.getRandomValues), the same entropy source used in TLS handshakes. It applies rejection sampling to filter out sequential runs, repeated digits, palindromes, and the 20 most statistically common PINs. A standard 4-digit numeric PIN provides E ≈ 13.29 bits of entropy across 10,000 combinations. That entropy drops to near zero if the PIN is guessable. This tool ensures it is not.

Limitations: entropy calculations assume uniform random distribution and a purely numeric keyspace (0 - 9). Physical security (shoulder surfing, skimming) is outside the scope of any software tool. Change your PIN periodically and never reuse it across institutions.

Formulas

PIN entropy quantifies the theoretical difficulty of guessing a randomly generated PIN. For a purely numeric keyspace of 10 digits (0 - 9) with PIN length n:

E = n ⋅ log₂(10) ≈ n × 3.3219 bits

Where E = entropy in bits, n = number of digits in the PIN. Total keyspace size: K = 10ⁿ.

Strength scoring uses pattern detection. The sequential run detector checks for ascending or descending sequences of length ≥ 3:

isSequential(d_i) =

{

TRUE if d_i+1 − d_i = ±1 for ≥ 3 consecutiveFALSE otherwise

Where d_i = digit at position i. The repetition detector flags PINs where any single digit appears more than n2 times. Palindrome detection compares d_i = d_n−1−i for all i. The CSPRNG source crypto.getRandomValues draws from the operating system's entropy pool, which on modern systems collects from hardware interrupts, thermal noise, and timing jitter.

Reference Data

PIN Length	Total Combinations	Entropy (bits)	Brute-Force Time (3 tries/lockout)	Common Usage
4 digits	10,000	13.29	~3,333 lockout cycles	ATM, Debit Cards (ISO 9564)
5 digits	100,000	16.61	~33,333 lockout cycles	Some credit unions
6 digits	1,000,000	19.93	~333,333 lockout cycles	Mobile banking, Apple Pay
7 digits	10,000,000	23.25	~3,333,333 lockout cycles	High-security vaults
8 digits	100,000,000	26.58	~33,333,333 lockout cycles	Safe deposit boxes
Common Weak PINs (Blacklisted)
1234	~10.7% usage rate		Most common worldwide
0000	~1.6% usage rate		Second most common
1111	~1.2% usage rate		Repeated single digit
7777	~0.7% usage rate		"Lucky number" bias
2580	~0.6% usage rate		Vertical keypad column
1212	~0.4% usage rate		Alternating pattern
6969	~0.3% usage rate		Novelty bias
4321	~0.3% usage rate		Reverse sequential
1122	~0.2% usage rate		Paired digits
0852	~0.2% usage rate		Reverse vertical column
Security Standards
ISO 9564	PIN management and security for financial transactions
PCI DSS 4.0	Requirement 3.6 - Cryptographic key management procedures
ANSI X9.8	PIN entry device security requirements
EMV Spec	Chip card PIN verification (offline/online)
NIST SP 800-63B	Digital identity guidelines for memorized secrets

Frequently Asked Questions

Math.random() uses a pseudo-random number generator (PRNG) seeded from a predictable state. Its output can be reconstructed if the internal state is known. The Web Crypto API's crypto.getRandomValues() draws from the OS entropy pool (e.g., /dev/urandom on Linux, BCryptGenRandom on Windows), which collects physical entropy from hardware events. For security-critical values like PINs, CSPRNG is the only acceptable source.

Even a CSPRNG can produce 1234 or 0000 by chance. Research by Data Genetics analyzed 3.4 million 4-digit PINs and found that the top 20 most common PINs account for approximately 27% of all PINs in use. By rejecting these statistically over-represented combinations, the tool ensures generated PINs fall outside attacker priority lists. The rejection sampling re-rolls until a non-blacklisted PIN is produced, with negligible performance impact (blacklist is 20 entries out of 10,000 combinations).

Technically yes, but negligibly. For a 4-digit PIN: there are 10,000 total combinations. Excluding the ~20 blacklisted PINs, ~10 all-same-digit PINs, ~18 sequential runs (1234, 2345, ..., 9876, 6789 ascending+descending), and ~90 palindromes removes roughly 130 combinations. Adjusted entropy: log₂(9,870) ≈ 13.27 bits vs. the original 13.29 bits. The 0.02-bit reduction is irrelevant compared to the massive security gain from avoiding predictable patterns.

ISO 9564 specifies PIN lengths of 4 to 12 digits. Most ATM networks enforce exactly 4 digits. Some European banks allow 5 or 6. Mobile banking apps (Apple Pay, Google Pay) typically use 6 digits. If your bank supports 6+ digits, use them - each additional digit multiplies the keyspace by 10×, adding approximately 3.32 bits of entropy.

No. Generation occurs entirely client-side using your browser's crypto.getRandomValues(). No PIN is ever sent to a server, stored in localStorage, or written to cookies. The PINs exist only in volatile JavaScript memory and are eligible for garbage collection once you navigate away or close the tab. Your generation settings (length, count, rules) are saved to localStorage for convenience, but never the PIN values themselves.

Rejection sampling generates a candidate PIN, checks it against all active rules (no sequential, no repeated, no palindrome, not blacklisted), and discards non-conforming candidates. The process repeats until a valid PIN is found. Because each candidate is drawn uniformly from the CSPRNG, and rejection is deterministic based on the PIN's properties, the output distribution remains uniform over the accepted set. There is no bias introduced - every valid PIN has equal probability of being selected.