hashcat Forum

OK, if you say so.

Now I've a question @ epixoip

Quote:Please understand sha512crypt, aka SHA512(Unix), is *not* simply salted sha512. The "hex string" generated by Cain's Hash Calculator is just a raw sha512 hash, and is completely different -- and in no way compatible with -- sha512crypt in libc. The "ASCII string" that crypt outputs is base64-encoded, and is the result of 5,000 rounds of the sha512 algorithm.

You can use -m 1800 in the cpu version of Hashcat to crack the sha512crypt hashes from your shadow file.

I gues 5 ruonds means, that there is generated a SHA512 hash out of my pw and this string is passing the algorythm once again. This will be repeated for another 3 times and this hash will be encoded with base64 after this.

Now I looked up base64 at wikipedia and compared it with my linux string. There were some "." (dots) included in my hash but no "+", but in wikipedia was no ".", but a "+" for the value of "62". Am I right, when I think these two chars are both reprisented by the value of 62?

Beside that I tryed to convert a base64 saltto hex manually.
The bas64 strin contains of 13 chars, means 13 6bit-blocks means 78 bits. 78 ins't divisible by 8, so I think ther ware 2 zero bits more 0-bits at the end of the hex hash. But in this case 80 isn't divisible by 6 and to convert this string two 8bit-zero-blocks should had been added two the hash, because 96 is the next number which is divisble by 6. But in this case two "=" mus stand after the bas64-hash, which aren't there.

Is there something wrong in my calculation, or are they just droped out of the hash?

It's not the same Base64 encoding, a customized one (Based on Base64).

And it's 5000 rounds, not 3 or 5.

Really, really tricky, I like that. 5000 rounds, this explains why it lasts so long to crack this hash and why rainbow-tables are a good alternative. But the salt is so long, that rainbowtables would need too much hdd-space. Seems to be much more safer than anything else I tryed till now and seems to be nearly invulnurable by brute-force, and uncrackable in general if you use the right password.

Overall, it is more than 5000 sha512 operations because of the initialization part which is more complex as compared to md5crypt. There can be 30-40 additional sha512 hash operations depending on salt and password (the initialization part is particularily unfriendly to GPUs).

A good description of the algorithm can be found here:

https://www.vidarholen.net/contents/blog/?p=33