Access-Control UID Software
Utilities for RFID UID byte-order conversion, 4/7-byte representations, hexadecimal/binary inspection and historical data-protection experiments.
These utilities were developed to inspect, convert and compare UID values obtained from RFID readers with the representation used by the surrounding access-control software and database.
Different Representations of the Same Identifier
One recurring issue was that the byte sequence produced by a reader did not always match the textual representation stored in the database. In one test, a UID received as F23ACBD2 corresponded to D2CB3AF2 in the existing record.
The difference was about byte ordering and representation rather than a different logical card identity. I made that conversion explicit in the application and verified the result against the stored data.
This became an early binary-data lesson that remains relevant: expose byte boundaries and representation assumptions before applying a conversion.
Four- and Seven-Byte UID Work
Because the internship involved identifiers of different lengths, the conversion tools supported inspecting 4-byte and 7-byte values in hexadecimal and binary forms.
The objective was not only to print a final identifier. Intermediate representations were useful for diagnosing incorrect conversion logic.
Data-Protection Experiments
Some 2014 prototypes also experimented with cryptographic APIs rather than treating identifiers only as plain text. These were not modern access-control or key-management designs; they were early attempts to handle data representation and protection in the same workflow.
A readable UID is not itself an authentication guarantee; cloning and authorization policy belong to separate security questions.
Related Work
