First some theory:

AHamming codeis defined for numbers [n,k] where $\displaystyle n=2^r-1$ and $\displaystyle k=n-r$. Every k bits are encoded into n-bit codewords. Furthermore, every codeword in a Hamming code has a distance of minimum 3 to another codeword, which gives the ability of correcting 1 corrupt bit in each codeword (corrects 1 error per n-bits)

Having that said, please consider the[5,2] code(anonHamming code, as per definition above). Every 2 bits are encoded into a 5 bit codeword, i.e.

$\displaystyle

00 \to 00000$

$\displaystyle 01 \to 01011$

$\displaystyle 10 \to 10101$

$\displaystyle 11 \to 11110$

This code have the exact characteristics, as far as I can see, as the Hamming code - the distance between codewords is minimum 3, and it corrects 1 error in 5 bits.

How come, then, that it is not classified as a Hamming code? Is there any difference that I have missed?