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const letters := 52
var key : array 1 .. letters of string
var c : string

procedure createKey
for i : 1 .. letters
key (i) := ""
end for
var next : int
for i : 1 .. letters
loop
key (i) := chr (Rand.Int (33, 126))
next := 1
for j : 1 .. letters
if key (i) = key (j) and j not= i then
next := 0
end if
end for
exit when next = 1
end loop
end for
end createKey

createKey

fcn encrypt (message : string) : string
var encrypted : string := ""
for i : 1 .. length (message)
if ord (message (i)) <= 90 then
encrypted += key ((ord (message (i)) - 38))
else
encrypted += key ((ord (message (i)) - 96))
end if
end for
result encrypted
end encrypt

fcn getKey (key : array 1 .. letters of string) : string
var keyString : string := ""
for i : 1 .. letters
keyString += key (i)
end for
result keyString
end getKey

fcn decrypt (message : string, key : array 1 .. letters of string) : string
var decrypted : string := ""
for i : 1 .. length (message)
for j : 1 .. letters
if message (i) = key (j) then
if j <= 26 then
decrypted += chr (j + 96)
else
decrypted += chr (j + 38)
end if
end if
end for
end for
result decrypted
end decrypt

createKey

var option : int
var message : string
loop
put "1) encrypt"
put "2) decrypt"
put "3) show key"
put "4) exit"
put "what do you want to do?"
get option
cls
case option of
label 1 :
put "enter message"
get message
put encrypt (message), "\n"
label 2 :
put "enter message"
get message
put decrypt (message, key), "\n"
label 3 :
put getKey (key), "\n"
end case
exit when option = 4
end loop

Author:	Mazer [ Mon Mar 08, 2004 6:58 pm ]
Post subject:
I don't know a whole lot about encryption techniques but I do no that the exit statement should be inside the case construct if you don't want it to crash. (ie, "label 4: exit" and take out the exit when line, or add "label :" and leave the rest) It looks pretty good, by the way.

Author:	Andy [ Fri Apr 23, 2004 10:29 am ]
Post subject:
i made an simple encryption program in c++ too lazy to convert it to turing, so here's my encrypt and decrpt functions btw it only works for 10 letters max or something like that... //encryption program string encrypt(char word[]) { //used for holding data char tempword[15],final[15]; int val[15],j,tempval; string encrypted; //encrypt the data for (int i=0;i<strlen(word);i++) val[i]=i; for (i=0;i<strlen(word);i++) { j=rand()%strlen(word); tempval=val[i]; val[i]=val[j]; val[j]=tempval; } for (i=0;i<strlen(word);i++) { tempword[i]=word[val[i]]; final[i]=val[i]+48; } tempword[strlen(word)]='\0'; final[strlen(word)]='\0'; strcat(final,tempword); for (i=0;i<strlen(final);i++) final[i]+=((i%3)-1)i; encrypted=final; return encrypted; } //decryption program string decrypt(string word) { //used for holding data char tempword[15],final[15]; int val[15]; string decrypted; for (int i=0;i<word.length();i++) final[i]=word[i]; final[word.length()]='\0'; for (i=0;i<strlen(final);i++) final[i]-=((i%3)-1)i; for (i=0;i<strlen(final)/2;i++) { val[i]=final[i]-48; tempword[i]=final[i+(strlen(final)/2)]; } tempword[strlen(final)/2]='\0'; for (i=0;i<strlen(tempword);i++) final[val[i]]=tempword[i]; final[strlen(tempword)]='\0'; decrypted=final; return decrypted; } its simple but its pretty good

Author:	white_dragon [ Fri Apr 23, 2004 5:34 pm ]
Post subject:
WOW!!!! out of all da possibilities i got da same character! anywho. yeah just like Delta said, use someting else rather than tat. good job

Author:	WhatAmIDoing [ Fri Apr 23, 2004 8:43 pm ]
Post subject:
it's a good idea but it won't work. you can't change the encrypyion back if u want. a code is a set thing not random. but good try

Author:	Catalyst [ Fri Apr 23, 2004 10:17 pm ]
Post subject:
hes right u need way of saving or sending the key along (too many non-alpha numeric chars for the person to write down, the chr codes would be better) and inputting the key into the prog other wise u can only decrypt the message from the instance of the program that created it which makes it useless

Author:	jdworrow [ Sun Apr 25, 2004 9:00 am ]
Post subject:
Well, I'm still a little rough around the edges with things in Turing. But I liked the basics of the encryption program. Very good idea to move forward on. [/img]

Author:	WhatAmIDoing [ Wed Apr 28, 2004 11:24 am ]
Post subject:
here is my encryption program var sentence : string var number : int loop put "" put "Please enter your message:('exit' to quit) " .. get sentence : * exit when sentence = "exit" for i : 1 .. length (sentence) number := ord (sentence (i)) if number = 90 then number := 64 elsif number = 122 then number := 96 elsif number = 32 then number := 31 end if put chr ((number) + 1) .. end for end loop if u want to decrypt just keep typing in the letters and eventualyy yuo'll get back to original message