Secure PIN Generator
Secure PIN Generator creates digits using crypto.getRandomValues and rejection sampling, with requested length constrained from 4 to 32. It provides unbiased numeric generation, but a PIN remains a low-alphabet secret whose safety depends heavily on attempt limits, device binding, storage, and context.
Runs locally — files stay on your deviceHow many possibilities does a random six-digit PIN have?
One million, from 000000 through 999999; leading zeroes are valid in this generator.
A PIN is a string of digits, not necessarily a number
For n independently uniform decimal digits, there are 10^n possible strings. Treating the result as a number can discard leading zeroes and reduce the representation.
How it works
Choose a digit count. The browser samples random bytes, maps them without modulo bias to 0–9, and joins the digits; lengths below four or above 32 are clamped.
Key concepts
Leading zeroes matter
004281 is a six-digit PIN and should remain a string.
Rate limiting is essential
Even uniform short PIN spaces can be exhausted without attempt controls.
When to use it
- Create a random temporary numeric code.
- Generate a local test PIN.
- Demonstrate numeric search-space growth.
When not to use it
- Do not use a short PIN without strict retry limits.
- Do not store or transmit it in plain text.
- Do not assume the page provisions, expires, or binds the code to a user.
Worked examples
Six digits
- Input
Length 6- Expected output
A string from 000000 to 999999
Every six-digit sequence is available.
Minimum clamp
- Input
Length 2- Expected output
4 digits
The implementation enforces at least four.
Long numeric token
- Input
Length 16- Expected output
16 random digits
Storage must preserve leading zeroes.
Common mistakes
Parsing as an integer
Leading zeroes disappear. Correction: Store PINs as strings.
Allowing unlimited attempts
A small search space becomes easy to enumerate. Correction: Rate-limit, lock, expire, and monitor verification.
Calling generation a full OTP system
The page has no binding, delivery, expiry, or verification state. Correction: Use an authenticated server-side flow.
Best practices
- Use short expiry and strict attempt limits.
- Store only an appropriate protected verifier.
- Bind codes to a purpose and account.
Related operations and differences
Password Generator
Choose Password Generator when you need to generate a secure random password locally.; use Secure PIN Generator specifically for pin.
Basic Auth Header Generator
Choose Basic Auth Header Generator when you need to generate a Basic Authorization header locally.; use Secure PIN Generator specifically for pin.
HMAC Generator
Choose HMAC Generator when you need to create an HMAC using the browser Web Crypto API.; use Secure PIN Generator specifically for pin.
JWT Expiration Checker
Choose JWT Expiration Checker when you need to inspect the exp claim in a JWT.; use Secure PIN Generator specifically for pin.
JWT Header Viewer
Choose JWT Header Viewer when you need to decode a JWT header without verifying its signature.; use Secure PIN Generator specifically for pin.
JWT Payload Viewer
Choose JWT Payload Viewer when you need to decode a JWT payload without verifying its signature.; use Secure PIN Generator specifically for pin.
Limitations and privacy
- Generates text only.
- No delivery, expiration, storage, verification, throttling, or user binding.
- Device compromise can expose the result.
The entered value is processed locally in this browser. Avoid using an untrusted device for real credentials or secrets.
Frequently asked questions
Can a PIN start with zero?
Yes.
Is the output cryptographically random?
It uses crypto.getRandomValues.
Does it expire automatically?
No.
Does it enforce retry limits?
No.