encrypt not working in Leopard - temporary solution suggestion

[Mark Smith]

Josh, this came up during the summer, and here is an RC4  
implementation. It's 'symetrical' - (you use the same function in and  
out). You'll need to base64encode the output if you're sending over  
the internet, and base64Decode back again before decrypting.

put base64Encode(rc4(somePlainData, someSecretKey)) into  
someEncryptedData
....
put rc4(base64Decode(someEncrypedData), someSecretKey) into  
somePlainData




function rc4 pText, pKey
   -- initialize
   repeat with i = 0 to 255
     put i into S1[i]
   end repeat

   put 0 into i
   repeat with n = 0 to 255
     add 1 to i
     if i > length(pkey) then put 1 into i
     put charToNum(char i of pKey) into S2[n]
   end repeat

   put 0 into j
   repeat with i = 0 to 255
     put (j + S1[i] + S2[i]) mod 256 into j
     put S1[i] into temp
     put S1[j] into S1[i]
     put temp into S1[j]
   end repeat

   -- encrypt/decrypt
   put 0 into i ; put 0 into j
   repeat for each char c in pText
     put charToNum(c) into tChar

     put (i + 1) mod 256 into i
     put (j + S1[i]) mod 256 into j
     put S1[i] into temp
     put S1[j] into S1[i]
     put temp into S1[j]
     put (S1[i] + S1[j]) mod 256 into t
     put S1[t] into K

     put numToChar(tChar bitXor K) after tOutput
   end repeat

   return tOutput
end rc4


Best,

Mark

On 15 Dec 2007, at 02:59, Josh Mellicker wrote:
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> If anyone has something better, post it if ya got it!
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