September 2017 Update

Task/Vigen-re-cipher/Phix/vigen-re-cipher.phix

@@ -0,0 +1,22 @@
+enum type mode ENCRYPT = +1, DECRYPT = -1 end type
+
+function Vigenere(string s, string key, mode m)
+string res = ""
+integer k = 1, ch
+    s = upper(s)
+    for i=1 to length(s) do
+        ch = s[i]
+        if ch>='A' and ch<='Z' then
+            res &= 'A'+mod(ch+m*(key[k]+26),26)
+            k = mod(k,length(key))+1
+        end if
+    end for
+    return res
+end function
+
+constant key = "LEMON",
+         s = "ATTACK AT DAWN",
+         e = Vigenere(s,key,ENCRYPT),
+         d = Vigenere(e,key,DECRYPT)
+
+printf(1,"Original: %s\nEncrypted: %s\nDecrypted: %s\n",{s,e,d})