Proper mask
#1
Hi there!

I'm a totally newbie so I'm asking for you help...

I have a md5-file with passwords "????-????-????-????", where ? is 0123456789ABCDEF.

So I'm trying to bruteforce via a mask:
Code:
>hashcat64 -m 0 -a 3 -i --increment-min=19 --increment-max=19 work.md5 ?H?H?H?H-?H?H?H?H-?H?H?H?H-?H?H?H?H
hashcat (v5.1.0) starting...

* Device #1: WARNING! Kernel exec timeout is not disabled.
            This may cause "CL_OUT_OF_RESOURCES" or related errors.
            To disable the timeout, see: https://hashcat.net/q/timeoutpatch
OpenCL Platform #1: NVIDIA Corporation
======================================
* Device #1: GeForce GTX 1080 Ti, 2816/11264 MB allocatable, 28MCU

Hashes: 99 digests; 99 unique digests, 1 unique salts
Bitmaps: 16 bits, 65536 entries, 0x0000ffff mask, 262144 bytes, 5/13 rotates

Applicable optimizers:
* Zero-Byte
* Early-Skip
* Not-Salted
* Not-Iterated
* Single-Salt
* Brute-Force
* Raw-Hash

Minimum password length supported by kernel: 0
Maximum password length supported by kernel: 256

ATTENTION! Pure (unoptimized) OpenCL kernels selected.
This enables cracking passwords and salts > length 32 but for the price of drastically reduced performance.
If you want to switch to optimized OpenCL kernels, append -O to your commandline.

Watchdog: Temperature abort trigger set to 90c

Integer overflow detected in keyspace of mask: ?H?H?H?H-?H?H?H?H-?H?H?H?H-?H?H?H?H

Started: Wed Jul 10 02:38:06 2019
Stopped: Wed Jul 10 02:38:12 2019

How to fix the overflow error? Or is not a feasible task even for md5?

Thank you!
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#2
if you calculate how many passwords you are trying you will see that you are getting 16 to the power 16 or 18446744073709551616 passwords (18 billion billion).

On this post https://hashcat.net/forum/thread-8428.html you can see that 2x tesla v100 can do 100.1 GH/s for MD5. It would take that system 6 years to run through this space (assuming it can maintain a steady pace of 100 GH/s).

What you are searching is just too big, there is no way to fix the overflow error. The only thing you can do is test smaller ranges.
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