Plastic Key Cards for Business: Benefits, Types and Security

Note (September 2026): This article was updated to correct an overstated claim that key cards stop strangers from getting into a building. Older 125 kHz proximity cards can be copied with inexpensive tools, so the card technology chosen matters.

Plastic key cards replace metal keys with credit-card-sized credentials that an electronic reader checks before unlocking a door. For a business, the main benefits are that a lost card can be switched off instead of changing the locks, access can be limited by door and time, and every entry can be logged. Security depends on the card type: encrypted 13.56 MHz smart cards are much harder to copy than older 125 kHz proximity cards.

Key Takeaways

• Most key cards follow the ISO/IEC 7810 ID-1 size, also called CR-80: 85.60 by 53.98 mm, the same as a bank card.
• Unlike mechanical keys, electronic access control can restrict a card to certain doors, days and times, and it records each attempt.
• Common types include magnetic stripe, Wiegand, 125 kHz proximity, 13.56 MHz smart cards and phone-based mobile credentials.
• Legacy 125 kHz prox cards send an unencrypted code and can be copied with cheap devices; MIFARE Classic encryption was publicly broken in 2008.
• For new systems, encrypted smart cards or mobile credentials, set up by a qualified installer, are the safer choice.

Being the owner of a business is not easy, but more than worth the effort that is invested. In order to be successful in the world of small business, a person will have to find ways to make their company more efficient. When it comes to the security of a commercial building, a business owner will have to take the time to research their options.

Reasons Why Plastic Key Card Technology Is Worth Using

Using an access control system is a great way for a person to get the security they are after. Here are some of the reasons why using plastic card technology is important and beneficial for a business owner.

These Cards Are Durable

The first benefit that comes along with using these types of cards is that they are very durable. The last thing that any business owner wants is to replace the keys to their doors due to them breaking on a regular basis. There are a number of different cards out there and all of them have a different level of quality. The only way you will be able to find the right one for your needs is by taking the time to do a bit of research.

An Efficient Way to Open Doors

The next benefit that comes along with using these key cards is that they are an efficient way to open doors. You will be able to activate one of these cards in minutes, which will allow you to grant access to guests and vendors with ease. With traditional keys, you will have a very hard time getting this type of access granted in a short amount of time. Rather than having to deal with the inconvenience of leading guests around, you can get an access control system and allow them to roam around on their own.

Lowers Risk for a Business Owner

When this type of technology is set up well, it makes it much harder for strangers to get into a building, although no card system removes that risk entirely. Each card used in this type of system has to be enrolled in the building’s access control system before it will open a door. This makes it harder for thieves to get in with a lost or stolen card, because that card can be switched off, and it allows a business to restrict access to certain parts of the building. Older 125 kHz proximity cards, however, can be copied with inexpensive tools, so the card technology matters (see the security section below). Having this type of control is a great way for a business owner to find out who is going where and what they are doing.

The investment made in an access control system can pay off over time through fewer lock changes, entry records and tighter control, although the return depends on the size of the building and the system chosen. Be sure to find the right professionals to install this system to ensure it is done the right way. 🙂

What Is a Plastic Key Card?

A plastic key card is a flat, rectangular credential that stores a code a door reader accepts before releasing the lock. According to the Wikipedia entry on keycard locks, most key cards share the dimensions of a credit card, the ISO/IEC 7810 ID-1 format, and the invention is credited to Tor Sørnes in the 1970s.

The ID-1 format, also known as CR-80, measures 85.60 by 53.98 mm with rounded corners. ISO/IEC 7810 sets a card thickness of 0.76 mm (plus or minus 0.08 mm) and covers resistance to bending, chemicals, heat, light and humidity, which is where much of a key card’s durability comes from.

How Does a Key Card Access Control System Work?

An electronic access control system works in a short sequence each time a card is presented:

1. The reader picks up the card’s credential, usually a number.
2. The reader passes that number to a control panel, often over a Wiegand connection.
3. The control panel compares the number with its access control list for that door.
4. If the card is allowed, a relay unlocks the door for a set time; if not, the door stays locked.
5. Both granted and refused attempts are recorded, and the system can raise an alarm if a door is forced or held open too long.

The original 26-bit Wiegand format carries an 8-bit facility (site) code of 0 to 255 and a 16-bit card number of 0 to 65,535. Many manufacturers later created longer formats of their own, so readers and panels from different brands are not always compatible. This guide to access control system installation covers the planning side in more detail.

Types of Key Cards Compared

According to the keycard lock entry on Wikipedia, some systems can place the credential in a digital wallet such as Apple Wallet or Google Wallet, removing the need for a physical card.

Key Cards vs. Traditional Keys

Are Plastic Key Cards Secure?

Plastic key cards are only as secure as the technology inside them. Legacy 125 kHz proximity cards transmit a fixed facility code and card number without encryption. In a hands-on test, the security research publication IPVM reported that a card copier bought for $30 captured a 125 kHz HID prox card in less than 5 seconds from under an inch away, and it recommended moving to encrypted 13.56 MHz formats.

Encrypted smart cards have weaknesses too. The Crypto-1 cipher used in NXP’s MIFARE Classic was partly reverse-engineered in December 2007 and fully disclosed by researchers at Radboud University in March 2008. After a further attack on hardened MIFARE Classic EV1 cards in 2015, NXP recommended that users migrate to higher-security products; MIFARE Plus and MIFARE DESFire use AES encryption.

Because a card can be lent or stolen, higher-risk areas such as server rooms often add a second factor, such as a PIN or a biometric check, so that a card alone does not open the door. The pros and cons of biometric authentication are worth weighing before adding it. Card access also works best alongside often-overlooked business security practices.

How to Choose a Key Card System for a Business

1. List the doors and zones. Note which areas need restricted access, such as stock rooms, server rooms or cash offices.
2. Pick an encrypted credential. For new installations, choose 13.56 MHz smart cards with current encryption, or mobile credentials, rather than 125 kHz prox or MIFARE Classic.
3. Plan a migration if you already use prox. HID Global, for example, sells dual-frequency Seos + Prox cards designed to move sites from 125 kHz to 13.56 MHz in stages.
4. Check compatibility. Confirm the card format works with the readers and control panel, since many Wiegand formats are proprietary.
5. Set access rules and review records. Give each person only the access their job needs, and remove cards as soon as someone leaves.
6. Use a qualified installer. A professional can size the system, wire the readers correctly and plan for power cuts, since some locks keep a mechanical key bypass.

Access control is often paired with video surveillance; this comparison of Wi-Fi vs. wired security cameras covers the main camera options.

Privacy Considerations

Because every entry can be recorded, key card systems raise privacy questions, as the Wikipedia entry on keycard locks notes. A business should tell staff and visitors what is recorded, who can see the records and how long they are kept, and follow the data protection law that applies where it operates.

Frequently Asked Questions

What size is a plastic key card?

Most plastic key cards use the ISO/IEC 7810 ID-1 size, also called CR-80: 85.60 by 53.98 mm and about 0.76 mm thick. This is the same size as a standard bank card.

Can key cards be copied?

Some can. Legacy 125 kHz proximity cards send an unencrypted number and can be copied with inexpensive devices in seconds. Encrypted 13.56 MHz smart cards are much harder to copy, although the MIFARE Classic cipher has been broken since 2008.

What is the difference between 125 kHz and 13.56 MHz cards?

125 kHz cards are low-frequency proximity cards that transmit a fixed code with no encryption. 13.56 MHz cards are high-frequency smart cards with a chip that can use encryption, typically read at 2 to 10 cm under ISO/IEC 14443.

What happens if an employee loses a key card?

The administrator removes the lost card from the access control list, so it no longer opens any door, and issues a new one. With mechanical keys, the locks would have to be re-keyed instead.

Can a phone replace a plastic key card?

Yes, on systems that support mobile credentials. The credential can be stored in a digital wallet such as Apple Wallet or Google Wallet and read by the door reader like a contactless card.

Powered by