I'm using owasp EnDe web-based tool to understand nibbles and encoding in general. This online utility in my knowledge is the best free resource avaiable for anyone who is interested to learn encoding techniques.
I'm testing a sample input which is
Now, the results of encoding it based upon first nibble and second nibble is given as
A simple representation in hex of above sample input is
61 62 63 64 77 78 79 7a .
Can someone explain how it relates to the use in this tool?
For those who are interested in download owasp live cd here is the link http://appseclive.org/content/downloads
With some help from guys at stackexchange sisters I'm able to figured out the messy stuff. The whole encoding works like this.
Actually i was confusing in nibble 1 and nibble 2 definition in the tool. In theory nibble 1 should refer to high nibble and nibble 2 as low nibble. I was just confused in the use of nibbles format in the tool.
Now consider this. enDe tool takes entire set (abcdwxyz) and convert it into now the tools converts it like this
36,1,36,2,36,3,36,4,37,7,37,8,37,9,37,A based upon following logic.
For string (abcd) it writes as 36,1,36,2,36,3,36,4 by picking on e.g
'a' -> hex (61) -> chr(36) At the end appending 1 on left side as 36,1
Now, when i choose nibble 2 it translates abcdwxyz as 'a' -> hex (61) -> chr(31) At the end appending 1 on left side as 6,31
Now, two things to notice here is that in nibble 1 (encoding) msb(6) is used to get hex equivalent 36 for nibble 2 encoding lsb(1) is used to get hex equivalent 31 appending lsb before result (6,31). I'm still little confused about the use and placement of nibbles I hope someone in here would take time to comment and explain more.
I hope this explanation others to understand the use of such useful tool and a little a feedback on this little research from the site gurus would be a plus too:)