V adfgvx = ‘ADFGVX’

F encrypt(plainText, polybius, key)
   V s = ‘’
   L(ch) plainText
      L(r) 6
         L(c) 6
            I polybius[r][c] == ch
               s ‘’= :adfgvx[r]‘’:adfgvx[c]

   DefaultDict[Char, String] cols
   L(ch) s
      cols[key[L.index % key.len]] ‘’= ch

   V result = ‘’
   L(k) sorted(cols.keys())
      I !result.empty
         result ‘’= ‘ ’
      result ‘’= cols[k]
   R result

F decrypt(cipherText, polybius, key)
   V skey = sorted(key)
   V cols = [‘’] * key.len
   V idx = 0
   L(col) cipherText.split(‘ ’)
      cols[key.findi(skey[idx])] = col
      idx++

   V s = ‘’
   L(i) 0 .< key.len
      L(col) cols
         I i < col.len
            s ‘’= col[i]

   V result = ‘’
   L(i) (0 .< s.len - 1).step(2)
      V r = :adfgvx.findi(s[i])
      V c = :adfgvx.findi(s[i + 1])
      result ‘’= polybius[r][c]
   R result

V polybius = [[Char("\0")] * 6] * 6
V alphabet = ‘ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789’
random:shuffle(&alphabet)
L(r) 6
   L(c) 6
      polybius[r][c] = alphabet[6 * r + c]

print("6 x 6 Polybius square:\n")
print(‘  | A D F G V X’)
print(‘---------------’)
L(row) polybius
   print(adfgvx[L.index]‘ | ’row.join(‘ ’))

V words = File(‘unixdict.txt’).read().split("\n").filter(w -> w.len == 9 & w.len == Set(Array(w)).len)
V key = random:choice(words).uppercase()
print("\nThe key is "key)

V PlainText = ‘ATTACKAT1200AM’
print("\nPlaintext : "PlainText)

V cipherText = encrypt(PlainText, polybius, key)
print("\nEncrypted : "cipherText)

V plainText = decrypt(cipherText, polybius, key)
print("\nDecrypted : "plainText)