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https://github.com/ryancdotorg/brainflayer

A proof-of-concept cracker for cryptocurrency brainwallets and other low entropy key algorithms.
https://github.com/ryancdotorg/brainflayer

bitcoin brainwallet cryptography ethereum password-cracker secp256k1

Last synced: about 2 months ago
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A proof-of-concept cracker for cryptocurrency brainwallets and other low entropy key algorithms.

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README 

        
Brainflayer

===========



⚠️ *I am not currently maintaining Brainflayer. It has acomplished [what I set out to do with it](https://rya.nc/defcon-brainwallets.html), and the work that went into it brought about a major inflection point in my career, but I have moved on to other things. Someday, I may come back to it, but don't count on that.* ⚠️



I am currently [suing the British Government](https://www.leighday.co.uk/news/news/2023-news/legal-challenge-urges-government-to-give-legal-recognition-to-nonbinary-people/). If you've found my work useful...



**...please donate to my [crowdfunding effort](https://www.crowdjustice.com/case/non-binary-recognition/)**.



Description

-----------



Brainflayer is a Proof-of-Concept brainwallet cracking tool that uses

[libsecp256k1](https://github.com/bitcoin/secp256k1) for pubkey generation.

It was originally released as part of my DEFCON talk about cracking brainwallets

([slides](https://rya.nc/dc23), [video](https://rya.nc/b6), [why](https://rya.nc/defcon-brainwallets.html)).



The name is a reference to [Mind Flayers](https://en.wikipedia.org/wiki/Illithid),

a race of monsters from the Dungeons & Dragons role-playing game. They eat

brains, psionically enslave people and look like lovecraftian horrors.



The current release is more than four times faster than the DEFCON release, and

many features have been added.



If brainflayer is useful to you, please get in touch to let me know. I'm very

interested in any research it's being used for, and I'm generally happy to

collaborate with academic groups.



Disclaimer

----------

Just because you *can* steal someone's money doesn't mean you *should*.

Stealing would make you a jerk. Don't be a jerk.



No support will be provided at this time, and I may ignore or close issues

requesting support without responding.



THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE

LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

POSSIBILITY OF SUCH DAMAGE.



Usage

-----



### Basic



Precompute the bloom filter:



`hex2blf example.hex example.blf`



Run Brainflayer against it:



`brainflayer -v -b example.blf -i phraselist.txt`



or



`your_generator | brainflayer -v -b example.blf`



### Advanced



Brainflayer's design is heavily influenced by [Unix philosophy](https://en.wikipedia.org/wiki/Unix_philosophy).

It (mostly) does one thing: hunt for tasty brainwallets. A major feature it

does *not* have is generating candidate passwords/passphrases. There are plenty

of other great tools that do that, and brainflayer is happy to have you pipe

their output to it.



Unfortunately, brainflayer is not currently multithreaded. If you want to have

it keep multiple cores busy, you'll have to come up with a way to distribute

the work yourself (brainflayer's -n and -k options may help). In my testing,

brainflayer benefits significantly from hyperthreading, so you may want to

run two copies per physical core. Also worth noting is that brainflayer mmaps

its data files in shared memory, so additional brainflayer processes do not

use up that much additional RAM.



While not strictly required, it is *highly* recommended to use the following

options:



* `-m FILE` Load the ecmult table from `FILE` (generated with `ecmtabgen`)

            rather than computing it on startup. This will allow multiple

            brainflayer processes to share the same table in memory, and

            signifigantly reduce startup time when using a large table.



* `-f FILE` Verify check bloom filter matches against `FILE`, a list of all

            hash160s generated with

            `sort -u example.hex | xxd -r -p > example.bin`

            Enough addresses exist on the Bitcoin network to cause false

            positives in the bloom filter, this option will suppress them.



Brainflayer supports a few other types of input via the `-t` option:



* `-t keccak` passphrases to be hashed with keccak256 (some ethereum tools)



* `-t priv` raw private keys - this can be used to support arbitrary

            deterministic wallet schemes via an external program. Any trailing

            data after the hex encoded private key will be included in

            brainflayer's output as well, for reference. See also the `-I`

            option if you want to crack a bunch of sequential keys, which has

            special speed optimizations.



* `-t warp` salts or passwords/passphrases for WarpWallet



* `-t bwio` salts or passwords/passphrases for brainwallet.io



* `-t bv2`  salts or passwords/passphrases for brainv2 - this one is *very* slow

            on CPU, however the parameter choices make it a great target for GPUs

            and FPGAs.



* `-t rush` passwords for password-protected rushwallets - pass the fragment (the

            part of the url after the #) using `-r`. Almost all wrong passwords

            will be rejected even without a bloom filter.



Address types can be specified with the `-c` option:



* `-c u` uncompressed addresses



* `-c c` compressed addresses



* `-c e` ethereum addresses



* `-c x` most signifigant bits of public point's x coordinate



It's possible to combine two or more of these, e.g. the default is `-c uc`.



An incremental private key brute force mode is available for fans of

[directory.io](http://www.directory.io/), try



`brainflayer -v -I 0000000000000000000000000000000000000000000000000000000000000001 -b example.blf`



See the output of `brainflayer -h` for more detailed usage info.



Also included is `blfchk` - you can pipe it hex encoded hash160 to check a

bloom filter file for. It's very fast - it can easily check millions of

hash160s per second. Not entirely sure what this is good for but I'm sure

you'll come up with something.



Building

--------



Should compile on Linux with `make` provided you have the required devel libs

installed (at least openssl and gmp are required along with libsecp256k1's

build dependencies). I really need to learn autotools. If you file an issue

about a build failure in libsecp256k1 I will close it.



Dependencies should install with



```

apt install build-essential libgmp-dev libssl-dev

```



Supported build target is currently Ubuntu 20.04 on amd64/x86_64. Issues with

building for other platforms probably won’t be fixed. In particular, Kali Linux

is *not* supported. Support for operating systems other than Linux would require

extensive refactoring of Brainflayer's memory optimizations and is not happening.



Redistribution of compiled `brainflayer` binaries is prohibited, and

unauthorized binaries probably contain malware.



Authors

-------



The bulk of Brainflayer was written by Ryan Castellucci. Nicolas Courtois and

Guangyan Song contributed the code in `ec_pubkey_fast.c` which more than

doubles the speed of public key computations compared with the stock secp256k1

library from Bitcoin. This code uses a much larger table for ec multiplication

and optimized routines for ec addition and doubling.