const dict1 = {
'A'
: 1,
'B'
: 2,
'C'
: 3,
'D'
: 4,
'E'
: 5,
'F'
: 6,
'G'
: 7,
'H'
: 8,
'I'
: 9,
'J'
: 10,
'K'
: 11,
'L'
: 12,
'M'
: 13,
'N'
: 14,
'O'
: 15,
'P'
: 16,
'Q'
: 17,
'R'
: 18,
'S'
: 19,
'T'
: 20,
'U'
: 21,
'V'
: 22,
'W'
: 23,
'X'
: 24,
'Y'
: 25,
'Z'
: 26};
const dict2 = {0:
'Z'
, 1:
'A'
, 2:
'B'
, 3:
'C'
, 4:
'D'
, 5:
'E'
,
6:
'F'
, 7:
'G'
, 8:
'H'
, 9:
'I'
, 10:
'J'
,
11:
'K'
, 12:
'L'
, 13:
'M'
, 14:
'N'
, 15:
'O'
,
16:
'P'
, 17:
'Q'
, 18:
'R'
, 19:
'S'
, 20:
'T'
,
21:
'U'
, 22:
'V'
, 23:
'W'
, 24:
'X'
, 25:
'Y'
};
function
encrypt(message, shift) {
let cipher =
''
;
for
(let i = 0; i < message.length; i++) {
const letter = message[i];
if
(letter !==
' '
) {
const num = (dict1[letter] + shift) % 26;
cipher += dict2[num];
}
else
{
cipher +=
' '
;
}
}
return
cipher;
}
function
decrypt(message, shift) {
let decipher =
''
;
for
(let i = 0; i < message.length; i++) {
const letter = message[i];
if
(letter !==
' '
) {
const num = (dict1[letter] - shift + 26) % 26;
decipher += dict2[num];
}
else
{
decipher +=
' '
;
}
}
return
decipher;
}
function
main() {
let message =
"GEEKS FOR GEEKS"
;
let shift = 13;
let result = encrypt(message.toUpperCase(), shift);
console.log(result);
message =
"TRRXF SBE TRRXF"
;
shift = 13;
result = decrypt(message.toUpperCase(), shift);
console.log(result);
}
main();