| Author | Message | Time |
|---|---|---|
| warz | I've been reading up on SHA1, in order to better understand what CheckRevision is doing, and I see that it's taking one parameter from the stack - pointer to the data to be sha1'd. Does SHA1 only take one parameter, and create the 160-bit digest simply based on that alone? Or, is there other factors that can influence the output of this? It looks like lockdown is incrementing a second argument, the value returned from storm.350, while it loops around the SHA1 function, as well as inside of the SHA1 function. It SHA1'd the data three times. | November 6, 2006, 2:12 AM |
| JoeTheOdd | If I understand correctly, it's like MD5. It hashes the data, and that's it. If you wanted to hash it with a "key" or "seed", it'd be perfectly legit to append or preappend that directly onto the data, though. EDIT - I don't know what storm.350 does, but I bet it's a seed of some sort, or makes a seed from the server/client tokens or something. But then again if CheckRevision()'s signature didn't change then you couldn't be passing the tokens to it in the first place.. | November 6, 2006, 3:31 AM |
| warz | Well, after looking at an actual sha1 implementation in C, it looks like the value returned from storm.350, or from within storm.350, is one of the parameters for SHA1Transform. | November 6, 2006, 3:51 AM |
| Ersan | [quote author=Joe[x86] link=topic=15988.msg160853#msg160853 date=1162783911]If I understand correctly, it's like MD5. It hashes the data, and that's it. If you wanted to hash it with a "key" or "seed", it'd be perfectly legit to append or preappend that directly onto the data, though. [/quote] This is called salting, and it's very likely that this is what it's doing. salt = seed Try: SHA1 ( salt + value ) or SHA1 ( value + salt ) or SHA1 ( salt + value + salt ) Most common usage. | November 10, 2006, 12:30 AM |
| UserLoser | [quote author=warz link=topic=15988.msg160856#msg160856 date=1162785063] Well, after looking at an actual sha1 implementation in C, it looks like the value returned from storm.350, or from within storm.350, is one of the parameters for SHA1Transform. [/quote] You don't have to worry about SHA1Transform, only SHA1Init (no brainer), SHA1Update and SHA1Final. SHA1Update calls SHA1Transform for you | November 10, 2006, 12:41 AM |
| warz | Yes. Also, it doesn't appear to be using a salt. | November 10, 2006, 2:28 AM |