The Patterns That Make Your PIN Easy to Crack

PIN codes use structures to categorize, making some types inherently riskier than others:

  • Same Digits: Repeating the same digit four times, like “1111” or “0000.”
  • Consecutive: Numbers that increase or decrease sequentially, like “1234” or “4321.”
  • Grouped: Digits that repeat in pairs or patterns, such as “1122” or “5566.”
  • Year-like: PINs that resemble years, especially from the 1900s or 2000s.

  • Random: PINs that don’t follow any obvious pattern.

PINs with the same digits are the worst, as they can be easily cracked by AI in 0.44 seconds on average. That’s faster than you can even unlock your phone.

Here’s the average time to crack different types of PINs:

The 10 PIN Codes Easiest to Crack by AI

If you recognize any of the PINs below that you have used for passwords, change them immediately. These are the top 10 most easily-cracked PIN codes, all of which share the same feature: repeated digits.


Claiming the top position is “5555”, taking only 0.37 seconds to crack. Followed closely behind is “2222”, which takes 0.41 seconds. These top 10 worst PINs are extremely vulnerable and exposed to AI-based cracking tools because their patterns, with the same number 4 times, are too recognizable. Change your PIN now if you have any of these sequences in your passcode to protect your information.

Conclusion

The combination of simple digit patterns in your PIN code creates an easy target for AI hacking tools. Codes like 5555 and 2222 take less than half a second for hacking tools to crack them, which easily exposes your account data to unauthorized access.

Uku Tomikas - CEO of business messaging platform Messente commented on the findings:

“The fact that AI can crack commonly used PINs should be a major wake-up call for both individuals and businesses. For businesses using SMS or PIN-based verification flows, weak PIN codes can leave customer accounts vulnerable, even when two-factor authentication is enabled.


“I recommend that businesses implement multi-layered authentication, such as randomized one-time passwords (OTPs), time-based tokens, and PIN fallback mechanisms to reduce the impact of predictable codes

“Messente’s secure messaging and verification solutions help reduce risks by ensuring that your PINs and OTPs are delivered reliably and backed by modern security standards.”

Methodology

To reveal the most vulnerable PIN codes, we analyzed real-world data breach datasets and trained a supervised machine learning model to detect common patterns in PIN selection.

A supervised machine learning model was developed and trained on the collected PIN dataset. The model was designed to learn patterns in PIN selection behavior and predict the most probable PIN codes.

To evaluate performance, the model was tested on a separate set of previously unseen PINs. We measured the model’s ability to accurately and quickly predict these PINs, focusing on guess success rate and efficiency.

For deeper analysis, PIN codes were classified into five distinct categories based on their structural patterns:

  • Consecutive: Sequences where digits increase or decrease consecutively (e.g., 1234, 4321).
  • Grouped: Sequences with adjacent identical digits (e.g., 1122, 5566).
  • Same Digits: Patterns where digits repeat in mirrored or alternating forms (e.g., 1221, 1212).
  • Random: PINs without any apparent pattern (e.g., 3975).
  • Year: PINs resembling years (e.g., 1987, 2023).

Each category was then analyzed and ranked based on predictability, highlighting which types of PINs are most susceptible to being compromised.