+- HP Forums (https://www.hpmuseum.org/forum)
+-- Forum: HP Software Libraries (/forum-10.html)
+--- Forum: General Software Library (/forum-13.html)
+--- Thread: (38G) Hill's Encryption System (/thread-4846.html)
(38G) Hill's Encryption System - Gerald H - 10-01-2015 10:16 AM
The following four programmes implement Hill's Cypher system for the HP 38G.
HILLSET stores the parameters, encyphering & decyphering matrices & additional cypher vector, in M9, M0 & M8.
The programme asks for an encyphering modulus, for English perhaps 26, & size of cyphering matrices & vector, conveniently 4 to fit on the screen.
ENCY encyphers the conformable matrix M1 & stores the result in M1.
DECY decyphers the conformable matrix M1 & stores the result in M1.
M1ADDV8 adds/subtracts the comformable vector M8 to the rows of M1.
For info on Hill's system see:
https://en.wikipedia.org/wiki/Hill_cipher
HILLSET
Code:
INPUT C;"Hill Cryptosystem"; "Modulus";" Cypher Modulus ► C";26:
INPUT S;"Hill Cryptosystem"; "Size";" Size of Cypher Matrix ► S";4:
IDENMAT(S)►M0:
FOR I=1 TO S STEP 1;
FOR J=1 TO S STEP 1;
IF I==J
THEN
IF RANDOM>.5
THEN
-1►M0(I,I):
END:
S►J:
ELSE
INT(C*(RANDOM))►M0(I,J):
END:
END:
END:
M0:
Ans*TRN(Ans):
MAKEMAT(Ans(I,J)MOD C,S,S
)►M9:
M0^-1:
MAKEMAT(
ROUND(Ans(I,J),0),S,S):
TRN(Ans)*Ans:
MAKEMAT(Ans(I,J)MOD C,S,S
)►M0:
MAKEMAT(INT(C*RANDOM),1,S)►M8:Code:
SIZE(M1):
Ans(1)►T:
SIZE(M9):
Ans(1)►S:
M1*M9:
MAKEMAT(Ans(I,J)MOD C,T,S
)►M1:
1:
RUN M1ADDV8:Code:
-1:
RUN M1ADDV8:
SIZE(M1):
Ans(1)►T:
SIZE(M0):
Ans(1)►S:
M1*M0:
MAKEMAT(Ans(I,J)MOD C,T,S
)►M1:Code:
Ans►V:
SIZE(M1):
MAKEMAT((M1(I,J)+V*M8(1,J))MOD C,Ans(1),S)►M1:RE: HP 38G: Hill's Encryption System - Gerald H - 03-04-2017 03:32 PM
Sorry, the programme HILLSET did not set up M0 efficiently, here is a more efficient version, the difference being in the line with the command "BREAK":
Code:
INPUT C;"Hill Cryptosystem"; "Modulus";" Cypher Modulus ► C";26:
INPUT S;"Hill Cryptosystem"; "Size";" Size of Cypher Matrix ► S";4:
IDENMAT(S)►M0:
FOR I=1 TO S STEP 1;
FOR J=1 TO S STEP 1;
IF I==J
THEN
IF RANDOM>.5
THEN
-1►M0(I,I):
END:
BREAK:
ELSE
INT(C*(RANDOM))►M0(I,J):
END:
END:
END:
M0:
Ans*TRN(Ans):
MAKEMAT(Ans(I,J)MOD C,S,S
)►M9:
M0^-1:
MAKEMAT(
ROUND(Ans(I,J),0),S,S):
TRN(Ans)*Ans:
MAKEMAT(Ans(I,J)MOD C,S,S
)►M0:
MAKEMAT(INT(C*RANDOM),1,S)►M8: