Paolo Veronelli wrote:
Is there any standard protocol for calculating a unique number from a
record/atom ?
The question is related to RSA signing records by authors.Any
consideration about this matter and oz can be helpful.
Waiting for replies, I completed the functor so we have a solution to
blame :P
I doubt the Hash procedure is reliable as based on the Pickle functor.
Is that serialization portable,repetibile on different platforms and
stable in time or planned to change in the future.
The last hypothesis could invalidate all the past-to-change signings.
I'm not concerned about code speed , but *any* suggestion on the code is
welcome.
Thanks again
Paolino
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% RSA functor %%%%%%%%%%%%%%%%
functor
import OS Pickle
export new:NewRSA verify:Verify sign:Sign
define
fun {ModPow B E M} % exponentiation under modulo
A={NewCell 1} CB={NewCell B}
proc {Loop E}
if E>0 then
if (E mod 2)==1 then A:=(@[EMAIL PROTECTED]) mod M end
CB:=(@[EMAIL PROTECTED]) mod M
{Loop (E div 2)}
end
end
in {Loop E} @A end
fun {RandIn P} % between (0..P) random generator
Y={OS.randLimits _ $}
fun {Rand X L}
C D=(P-1) div L
R=X+L*(if D>Y then C=true {OS.rand}
else C=false {OS.rand} mod D
end)
in
if C then {Rand R L*Y} else R+1 end
end
in {Rand 0 1} end
fun {Fermat P K} %Fermat test
for I in 0..K default:true return:R do
if {ModPow {RandIn P} P-1 P} \= 1 then {R false} end
end
end
fun {APrime Bits K} B={Pow 2 Bits} in % generate a prime of Bits
bits passing K Fermat tests
for return:R do A=1+{RandIn B} in
if {Fermat A K} then {R A} end
end
end
proc {Euclide A B X Y} % Extended Euclidean algorithm
if B==0 then X=1 Y=0 else
local X1 Y1 {Euclide B (A mod B) X1 Y1}
in X=Y1 Y=X1-Y1*(A div B) end
end
end
proc {NewRSA Bits K Pr M} X % generate an RSA key
P={APrime Bits K} Q={APrime Bits K} T=(P-1)*(Q-1)
in
M=P*Q {Euclide 65537 T X _} Pr=T+X mod T
end
fun {Hash V M}
N={NewCell 0} B={Pickle.pack V}
in
for I in 0..{ByteString.length B}-1 do
N:[EMAIL PROTECTED] B I}
end
@N mod M
end
fun {Sign V E M} {ModPow {Hash V M} E M} end
fun {Verify S V M} {ModPow S 65537 M}=={Hash V M} end
end
%% Test %%
% local
% NBits=256 FermatParameter=100 Private Modulus TestLoop=100
% in
% {NewRSA NBits FermatParameter Private Modulus}
% {Browse 'generated key'(private:Private modulus:Modulus)}
% {Browse success=
% for I in 0..TestLoop default:success return:R do F={RandIn Modulus} in
% if {Verify {Sign F Private Modulus} F Modulus} then skip else
{R failure} end
% end
% }
% end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% RSA functor ends %%%%%%%%%%%%%%%%
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