Attempting Cobra MD5 function

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Socoder -> Cobra -> Attempting Cobra MD5 function
Sun, 26 Aug 2007, 20:45
HoboBen	Hi, I'm trying to write a function to create MD5 hashes in Cobra. I've got the JavaScript MD5 source code (The C one was impossibly long!) And this excellent info too. Cobra can't yet take or return arrays with functions (though I have requested that), so a straight copy+paste hack job won't really work. It hasn't been too difficult to follow the general code behind the MD5 function, but in that second link, I don't really get this bit: In C code it appears that four auxiliary functions are defined as such: typedef unsigned int word; word f(word x, word y, word z) { return x & y \| ~x & z; } word g(word x, word y, word z) { return x & z \| y & ~z; } word h(word x, word y, word z) { return x ^ y ^ z; } word i(word x, word y, word z) { return y ^ (x \| ~z); } and f(00001111, 00110011, 01010101) = 01010011; g(00001111, 00110011, 01010101) = 00100111; h(00001111, 00110011, 01010101) = 01101001; i(00001111, 00110011, 01010101) = 10011100; // or -1100100 signed --v What does that all mean, and how would I Cobra-ise it? I sorta have a grasp of how that bit works, but I don't know what it's for, either. What does "~" mean in C? How does the whole \|&^~ thing work in the return part? Are these shorthand operations on some binary data or what? Finally, what's the difference between a hex or base-64 encoded string? Thank you, Hobo -=-=- blog \| work \| code \| more code
Mon, 27 Aug 2007, 02:55
Afr0	Never tried using MD5 myself, but based on that bit of code you posted, I can tell it appears to be equivalent to mathematical functions named F, G, H, I used in the algorithm. They are explained here under the section 'Algorithm'. As for the operators, I can give you the standard C names for most of them, but it's too early in the morning for me to bother to do any proper research into how they work in this particular case; & = Binary And (Can also be AddressOf, but doesn't seem to be in this case, since there aren't any pointers involved) \| = Inclusive Or ^ = Exclusive Or (Also referred to as Xor for BASIC users) ~ = One's compliment - This operator is unary (requires one operand) and has the efect of 'flipping' bits. -=-=- Afr0 Games Project Dollhouse on Github - Please fork!
Mon, 27 Aug 2007, 08:44
HoboBen	Thanks Afro, That helps a fair bit I'll see if I have any luck. Cheers -=-=- blog \| work \| code \| more code