For decades, the access card was the default way to open a door at work. Now the phone in everyone’s pocket can do the same job, using NFC or Bluetooth. That raises an obvious question for anyone planning or upgrading an access control system: should credentials stay on cards, move to phones, or both?
The honest answer depends on the site, the people, and the security requirement.
How each works
RFID smart cards contain a chip and antenna. When presented to a reader, the card communicates wirelessly — typically at 13.56 MHz for modern secure cards, or at 125 kHz for older proximity cards. The card needs no battery; the reader powers it.
Mobile credentials store an access credential on a smartphone or smartwatch. The phone communicates with a compatible reader, usually over NFC when held close or Bluetooth Low Energy when approaching. Credentials can often be issued and revoked remotely.
Comparing them
| Factor | RFID smart cards | Mobile credentials |
|---|---|---|
| Dependence on a phone | None | Needs a charged, compatible phone |
| Remote issuing and revoking | Physical card must be handed over | Can be issued and revoked remotely |
| Security | Strong with modern secure cards; weak with legacy proximity cards | Can use device security such as biometric unlock |
| Lost credentials | Lost cards must be reported and replaced | Phones are rarely left unattended; credentials can be revoked remotely |
| Upfront cost | Card cost per user | Compatible readers and platform licensing |
| Visitors and contractors | Easy to hand out temporary cards | Requires visitors to install or accept a credential |
| Industrial suitability | Works with gloves, in dust, without a phone | Phones may be restricted or impractical on some sites |
| Other uses | Can double as ID badge, canteen and attendance card | Consolidates onto a device users already carry |
When cards remain the better choice
Cards still win in several common situations:
- Industrial and manufacturing sites where workers wear gloves, phones are restricted on the floor, or devices are impractical.
- Defence and high-security facilities that do not allow personal phones inside controlled areas.
- Large contractor or shift workforces where issuing a card at the gate is simpler than enrolling personal phones.
- Multi-purpose credentials, where one card handles access, attendance, canteen payments, and photo identification.
When mobile credentials make sense
Mobile credentials suit:
- Corporate offices with a largely desk-based workforce who always carry phones.
- Organisations with high staff turnover or many sites, where remote issuing saves administrative effort.
- Environments where convenience drives adoption and card sharing is a known problem.
The security question
The security of a card system depends almost entirely on the card technology. Legacy 125 kHz proximity cards and MIFARE Classic cards can be copied with inexpensive tools. Modern cards such as MIFARE DESFire use AES-based authentication and are far more resistant. Our article on RFID access system security covers the details.
Mobile credentials can benefit from the phone’s own security, such as requiring a fingerprint or face unlock. But they also shift part of the risk to devices the organisation may not manage, and to the platform that issues credentials.
In short: a modern secure card and a well-implemented mobile credential can both be strong. A legacy proximity card is weak whichever way it is compared.
The hybrid approach
Most organisations will not switch overnight. A practical path is to:
- Upgrade the card technology first if legacy proximity cards are in use.
- Choose readers that support multiple credential types when replacing hardware, so mobile credentials can be added later without replacing readers again.
- Pilot mobile credentials with a group that will benefit most, such as office staff.
- Keep cards for visitors, contractors, industrial areas, and anyone without a compatible phone.
This lets a site modernise gradually without disrupting people who depend on the current system.
POXO supplies RFID smart cards in 125 kHz and 13.56 MHz formats, including MIFARE and DESFire, together with time attendance and access control devices and entrance control hardware. Talk to our team about planning a credential upgrade.
Frequently Asked Questions
Are mobile access credentials more secure than smart cards?
Not automatically. Both can be secure when well implemented. Modern smart cards such as MIFARE DESFire use strong encryption, and mobile credentials can use the phone’s biometric lock. Legacy 125 kHz proximity cards are the weak option and are easy to copy.
Will smart cards be replaced by phones?
Unlikely in the near term. Cards remain better suited to industrial sites, high-security facilities that restrict phones, contractors and visitors, and any use where one card also serves as ID, attendance, and canteen credential. Many organisations will use both.
Can existing access readers accept mobile credentials?
Only if they support the relevant technology, usually NFC or Bluetooth Low Energy, and the credential platform in use. Older card-only readers generally need replacing. When upgrading readers, choosing models that support multiple credential types avoids a second replacement later.
Which smart card technology should we choose for a new system?
For access control where security matters, a 13.56 MHz secure card such as MIFARE DESFire is generally recommended over legacy 125 kHz proximity cards or MIFARE Classic, both of which can be copied with inexpensive tools.