RosettaCodeData/Task/Substitution-cipher/Nim/substitution-cipher.nim
2023-07-01 13:44:08 -04:00

29 lines
792 B
Nim

import sequtils, strutils
proc encrypt(key: seq[char]; msg: string): string =
result.setLen(msg.len)
for i, c in msg:
result[i] = key[ord(c) - 32]
proc decrypt(key: seq[char]; msg: string): string =
result.setLen(msg.len)
for i, c in msg:
result[i] = chr(key.find(c) + 32)
when isMainModule:
import random
randomize()
# Build a random key.
var key = toSeq(32..126).mapIt(chr(it)) # All printable characters.
key.shuffle()
const Message = "The quick brown fox jumps over the lazy dog, who barks VERY loudly!"
let encrypted = key.encrypt(Message)
let decrypted = key.decrypt(encrypted)
echo "Key = “$#" % key.join()
echo "Message = “$#" % Message
echo "Encrypted = “$#" % encrypted
echo "Decrypted = “$#" % decrypted