How to detect in Android whether UID from NFC tag is random?

Question

I am working on an Android project which relies on the unique UID of a discovered NFC tag to process the tag. I extract this UID using the following code:

by         


        

Answer 1

This RFC: http://tools.ietf.org/html/rfc4122#section-4.1.3 defines the format of a UID; it includes a field indicating what type of UID it is:

 Msb0  Msb1  Msb2  Msb3   Version  Description

    0     0     0     1        1     The time-based version
                                     specified in this document.

    0     0     1     0        2     DCE Security version, with
                                     embedded POSIX UIDs.

    0     0     1     1        3     The name-based version
                                     specified in this document
                                     that uses MD5 hashing.

    0     1     0     0        4     The randomly or pseudo-
                                     randomly generated version
                                     specified in this document.

    0     1     0     1        5     The name-based version
                                     specified in this document
                                     that uses SHA-1 hashing.