Have You Ever Had 26 Bit Credential Capacity Problems?

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Brian Rhodes
Apr 18, 2017
IPVMU Certified

In electronic access, 26-bit format credentials are still commonly used.  Why?  Have you had data limit issues?

For context, consider that 26-bit first was introduced in the early 1970's with Wiegand Credentials. 26 bits is not much capacity.  Consider the approximate file size of a typical email is 75 Kilobytes, roughly 230% more data than what these credentials can contain.

In many cases, such a small size will not be an issue.  From an HID brochure:

The 26-bit format consists of 255 possible facility codes. Within each facility code, there are 65,535 unique card numbers

But modern credentials often carry more than just a unique number.  Cards/Identity templates often store names, addresses, contact numbers, biometric IDs, and even pictures.

The more information a card contains, the bigger it must be.

So again, do 26-bit cards work for you?  Where have they been a problem?

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Scott Lindley
Apr 19, 2017
Farpointe Data, Inc.

Given the figures above Brian, the 26-bit Wiegand format yields more than 17 million unique codes (facility code & ID number).  Data limits certainly exist within each facility code, as well as across the entire format.  In the early 70's that was perhaps a big number, but I believe most would agree that it's not today. 

Why does it persist today?  Here are a few reasons:  26-bit Wiegand was the first standardized interface between access devices, i.e. readers, and access panels.  It's been implemented on a global basis, with installation parameters widely understood.  Further, implementation is relatively low cost.  And, it is a relatively quick data transfer.

Today 26-bit Wiegand clearly continues to work for many users.  However it would certainly be interesting to hear where challenges have presented themselves.

 

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