Subject: [Cfrg] Password - final hash

From: Otto Ersek <[email-masked]>
Date: Wed, 2 Nov 2016 07:41:48 +0100

Hi,
No I don’t intend to just simply hash the final message!
Assume sha512 was to be selected as the underlying hash function

Transfer the submitted modified message appended with the positional 
data into M0 = (i,j) matrix.

1) Hash this matrix row by row → M1 = (i, 512)
2) then hash M1 column by column → M2 = (512, 512)
this populates user changes across the whole matrix, and then:

3) then hash M2 alternating between rows/columns in a predefined *) 
order multiple times over all entries

finally XOR the matrix thus we lose the “dimension” of a hash :-)

*) predefined = different for “all” messages pseudo-random but 
deterministic with a seed based on M2

Otto