public class DelegGen
extends java.lang.Object
This command-line tools generates sets of parameters for Makwa delegation. Usage:
DelegGen [ -it ] inParam workFactor outFile
The inParam
parameter is the name of a file containing an
encoded Makwa modulus, or an encoded Makwa private key. Processing
is (much) faster if a private key is used; but the obtained set is
equally valid otherwise.
The workFactor
parameter is the work factor for which the
set of parameters is created. Each set of parameters is specific to a
single work factor.
The resulting set of parameters is finally encoded into the
file whose name is provided as outFile
.
If either the "-genX
" or "-gen1
" option is used,
then the parameters will be created using the generator of invertible
quadratic residues included in the provided public or private key.
If that provided key does not include such a generator, then the
process fails and an error is reported.
-genX
is used, then the generated parameters will
include n+64
precomputed mask pairs, for a modulus of
n
bits; the resulting parameter file may be quite large
(a bit more than 1 megabyte for a 2048-bit modulus).-gen1
is used, then the generated parameters will
include only a single mask pair, and thus will be very compact
(less than 1 kilobyte for a 2048-bit modulus). However, this
method implies a larger computation overhead upon usage.Using the generator means that the delegation process is information theoretic secure, i.e. the delegation server learns nothing about the password even if it is assumed to have unlimited computing abilities (with the "classic" delegation parameters, such security is achieved "only" through computational infeasibility, i.e. leaking information requires a lot more computing power than is available on Earth today and in the foreseeable future). Since generator-based delegation implies a substantial computational overhead on the client (for a 2048-bit modulus, the overhead is 7x with "-genX", somehwat more with "-gen1"), it is recommended to use it only if it is required by a specific security or marketing model.