On the other hand, you wrote:
(Initialization and using DKEK - #6 by sc-hsm)
I don’t understand. If DKEK is 256 bits, and we use DKEK shares to compute DKEK with XOR, DKEK shares length should be equal length of DKEK (256 bits, not 128 bits), because XOR function output length is equal XOR function arguments length:
N-bits XOR N-bits gives N-bits outputs.
For two DKEK shares, lets say:
DKEK_shares_1, and
DKEK_shares_2 what is true:
DKEK = DKEK_shares_1 ^ DKEK_shares_2
or
DKEK = DKEK_shares_1 . DKEK_shares_2
or something else?
where ^ is C lang XOR operator
. is concatenation
I have no idea how to receive 256 bits long DKEK from 128 bits DKEK shares.