If you’re managing physical security for a building, office, or campus, one of the first questions you’ll run into is what type of access control cards to use. From simple magstripe badges to advanced Seos credentials, there are a lot of options—and not all of them are created equal.
Some formats are cheap but insecure. Others are more expensive but provide long-term protection against cloning and hacking. This article walks through the most common card formats, their strengths and weaknesses, and how to decide which one is right for your organization.
Why Access Control Card Formats Matter
The badge you hand an employee or contractor isn’t just a piece of plastic. It’s the first line of defense for your facility. Choosing the wrong card format can leave you exposed to cheap cloning devices and unauthorized access. Choosing the right one means you can secure doors, protect data, and even extend credentials into applications like printing and network login.
Common Access Control Card Types
Magnetic Stripe Cards
Magstripe badges are the old hotel keys and legacy employee cards you swipe through a reader.
- Pros: Low cost, easy to deploy, compatible with older systems.
- Cons: Almost no security. A simple skimmer can clone the data in seconds.
Verdict: Outdated and insecure. Avoid whenever possible.
Proximity (125kHz Prox) Cards
Still common in office buildings, these cards are read when held near a reader.
- Pros: Contactless, inexpensive, durable.
- Cons: Weak encryption or none at all. Formats like 26-bit Wiegand are especially vulnerable.
Verdict: Better than magstripe, but no longer considered secure.
MIFARE Classic
Once popular for transit systems and offices, MIFARE Classic cards run at 13.56 MHz and can hold more data.
- Pros: Multi-application capable, more advanced than Prox.
- Cons: Easy to clone with off-the-shelf tools.
Verdict: If you’re still using MIFARE Classic, it’s time to move on.
iCLASS Cards
HID’s iCLASS line introduced encryption and mutual authentication.
- Pros: Supports multiple applications, stronger security than Classic.
- Cons: Older iCLASS Standard can still be cloned if encryption keys aren’t managed properly.
Verdict: An improvement, but only secure if managed carefully.
iCLASS SE
This is HID’s upgraded version of iCLASS, built around a secure identity model.
- Pros: Stronger encryption, customizable keys, and harder to duplicate.
- Cons: Higher cost, requires upgraded readers.
Verdict: A solid middle ground for organizations upgrading from older formats.
DESFire (EV1, EV2, EV3)
MIFARE DESFire offers some of the strongest publicly available credential security. It uses AES encryption and supports multiple applications.
- Pros: Enterprise-level security, fast performance, flexible design.
- Cons: Higher cost and requires more planning to take full advantage.
Verdict: Excellent for hospitals, campuses, and large corporate facilities.
Seos
HID’s most advanced option, Seos works with both cards and mobile devices.
- Pros: High-level encryption, mobile credential support, and future-proof features.
- Cons: The most expensive option, and requires modern hardware.
Verdict: The top of the line. Ideal if you want maximum security and scalability.
Quick Security Ranking
From least secure to most secure:
- Magstripe
- Prox (125kHz)
- MIFARE Classic
- iCLASS Standard
- iCLASS SE
- DESFire EV1/EV2/EV3
- Seos
Which Card Format Should You Choose?
If you’re working with a limited budget and just need a basic system, Prox or iCLASS may get you by for now. But if security and long-term value matter, it’s worth investing in DESFire or Seos. These formats not only improve security but also set you up for mobile credentials and integrations down the road.
Final Thoughts
Not all access control cards are created equal. Magstripe and Prox may be cheap, but they leave your facility vulnerable. DESFire and Seos, while more expensive, provide the kind of security modern organizations need.
At 210 Solutions, we help businesses, schools, and healthcare facilities design and deploy access control systems that are secure, scalable, and built for the future.