Encryption Algorithm from PHP to Ruby (Vignere variant)

[shure]

I am a bit stuck with this. I have to interface with an api that uses a version of an encryption algorithm that they seem to have ripped from Typo3 written by Ari Kuorikoski.I need to create a ruby lib to interface with their api, so have to port their algorithm into ruby, and I am a bit out of my depth when it comes to encryption.This is the code:\[code\]private function keyED($txt) { $encrypt_key = md5($this->encrypt_key); $ctr=0; $tmp = ""; for ($i=0;$i<strlen($txt);$i++) { if ($ctr==strlen($encrypt_key)) $ctr=0; $tmp.= substr($txt,$i,1) ^ substr($encrypt_key,$ctr,1); $ctr++; } return $tmp; \[/code\]} \[code\]private function encrypt($txt){ srand((double)microtime()*1000000); $encrypt_key = md5(rand(0,32000)); $ctr=0; $tmp = ""; for ($i=0;$i<strlen($txt);$i++){ if ($ctr==strlen($encrypt_key)) $ctr=0; $tmp.= substr($encrypt_key,$ctr,1) . (substr($txt,$i,1) ^ substr($encrypt_key,$ctr,1)); $ctr++; } return base64_encode($this->keyED($tmp)); \[/code\]}The part that has me stumped is this, I have to write it for ruby 1.8.6 as that's the server that it will be on. And there's no XOR for strings... Not that I would understand it if there was.Any help, pointers, ideas would be much much appreciated.Thanks,JAddendum:I realize, I didn't put any code up, the only difficulty is actually the xor problem, but here is my code so far:\[code\]def xor(s1,s2) if s2.empty? then return s1 else a1 = s1.unpack("c*") a2 = s2.unpack("c*") a2 *= 2 while a2.length < a1.length return a1.zip(a2).collect {|c1,c2| c1 ^ c2}.pack("c*") end end def keyED(str) encrypt_key = Digest::MD5.digest(@key) ctr = 0 tmp = '' for i in 0...str.length do ctr = 0 if ctr == encrypt_key.length tmp << xor(str.slice(i,1), encrypt_key.slice(ctr,1)).to_s ctr = ctr + 1 end return tmp end # === Ported Code # This code was ported from Ari's Typo 3 Session Encryption def encrypt(str) encrypt_key = Digest::MD5.digest(rand(32000).to_s) ctr = 0 tmp = '' for i in 0...str.length do ctr=0 if ctr==encrypt_key.length tmp << encrypt_key.slice(ctr,1) << xor(str.slice(i,1), encrypt_key.slice(ctr,1)) ctr = ctr + 1 end return Base64.encode64(keyED(tmp)) end def decrypt(str) txt = keyED(str) tmp = '' for i in 0...txt.length do md = txt.slice(i,1) i = i + 1 tmp << xor(txt.slice(i,1),md) end puts "Decrypte string:#{Base64.decode64(tmp)}EOSTRING" end\[/code\]Update: Final working source, based on James helpful answer, major props! And to David Garamound.\[code\]def xor(s1,s2) raise ArgumentError, "Can't bitwise-XOR a String with a non-String" unless s2.kind_of? String raise ArgumentError, "Can't bitwise-XOR strings of different length" unless s1.length == s2.length (0..s1.length-1).collect { |i| s1 ^ s2 }.pack("C*")enddef keyED(txt,key) ctr,tmp = 0,'' key = Digest::MD5.hexdigest(key) for i in 0...txt.length do ctr = 0 if ctr == key.length str = xor(txt.slice(i,1),key.slice(ctr,1)) tmp << str ctr = ctr + 1 end return tmpenddef encrypt(txt,key) ctr,tmp = 0,'' ekey = Digest::MD5.hexdigest(rand(32000).to_s) for i in 0...txt.length do ctr = 0 if ctr == ekey.length str = xor(txt.slice(i,1), ekey.slice(ctr,1)) tmp << ekey.slice(ctr,1) << str ctr = ctr + 1 end return Base64.encode64(keyED(tmp,key))end\[/code\]