Btc brainflayer windows demo

Brainflayer is a Proof-of-Concept brainwallet cracking tool that uses libsecp256k1 for pubkey generation. It was originally released as part of my DEFCON talk about cracking brainwallets (slides, video, why).

The name is a reference to Mind Flayers, 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.

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.

Precompute the bloom filter:

hex2blf example.hex example.blf

Run Brainflayer against it:

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

your_generator | brainflayer -v -b example.blf

Brainflayer’s design is heavily influenced by 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, 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.

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

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.

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.

Brainflayer: The Best Brainwallet Cracking Tool

Brainflayer is a Proof-of-Concept brainwallet cracking tool that uses libsecp256k1 for pubkey generation. It was originally released as part of a DEFCON talk about cracking brainwallets. The released video is available at the end of the article.

Many researchers have spotted that cryptocurrency users are using guessable private keys to store their bitcoin and ethereum. Brainflayer can monitor thousands of private keys in seconds. If you know the private key then you own all bitcoins and ethereums in it.

Blockchain hackers are using such methods and they have stolen more than 50$ million in ethereum.

What is a private key?

A private key in the context of Bitcoin or Ethereum is a secret number that allows the crypto-coins to be spent. Every crypto-wallet contains one or more private keys, which are saved in the wallet file. Crypto-addresses are derived mathematically from the private keys.

Because the private key is the “ticket” that allows someone to spend bitcoins, it is important that these are kept secret and safe. Private keys can be kept on computer files, but are also often written on paper.

A bitcoin private key is a 256-bit number. An example in hexadecimal is the following :

From the above private key, the following public addresses are derived mathematically:

If you are more interested in the maths behind bitcoin, then check hackernoon’s article about elliptic curve cryptography.

Private keys themselves are almost never handled by the user, instead, the user will typically be given a seed phrase that encodes the same information as private keys.

Ethereum Seed Phrase

What is a Brainwallet?

A brain wallet is a standard wallet that the private key and relative public addresses are created by a hashed passphrase. The SHA-256 algorithm is regularly used by brainwallets as it produced 256-bit string which is the exact size as bitcoin’s private key.

Bitcoin Brainwallet Generator

In the above brainwallet generator, the word “password” is used as the secret passphrase. It is already mentioned that bitcoin address: 16ga2uqnF1NqpAuQeeg7sTCAdtDUwDyJav is used lately and it has in total received 0.356 BTC.

Hashed SHA256 “password” Bitcoin Address

It is obvious that you must not use brainwallets with seed phrases that are generated by a human.

Bruteforce can crack even the most difficult human-generated passphrases.

List of most known brainwallets :

How to Install Brainflayer

The following commands can be used to install brainflayer and the required dependencies on Kali or Ubuntu.

Compile Error Handling

A lot of people are troubled with compilations errors. The following changes on the Makefile file will help to overcome the errors.

The Man of Brainflayer

When everything is compiled, run it the flag -h for listing the available running options.

Create the Bloom Filter

According to Wikipedia, bloom filter is a space-efficient probabilistic data structure that is used to test whether an element exists in a set. False-positive matches are possible, but false negatives are not. In our case, there is a very small chance brainflayer that will return a cracked wallet that it is not actually cracked.

The next step is the creation of the bloom filter. A file which lists one bitcoin address per line is required. Then, addresses should be converted to Hash160 addresses. Finally, execute the following command :

For Ethereum bloom filter creation, no hash160 conversion is required.

Crack Bitcoin via Wordlist

After the bloom filter creation, everything is ready for brute-forcing. Grab your longest wordlist and attack! The following commands are the most common ones:

The sha256 algorithm is the default option.

Crack Ethereum via Wordlist

Similarly, the most common cracking options for ethereum are the following:

Parallel Cracking

Brainflayer does not support multi-thread functionality. For parallel cracking, you should run multiple instances with different -n parameter.

Private Key Scanner

Brainflayer supports cracking via incremental private keys with option -I . This method is extremely fast. A single modern core can scan more than 700.000 private keys per second.

Brainflayer Def Con Video

If you are still not satisfied, check for more information on def con video.

Brainflayer and Windows 10

In short, brainflayer is a tool that is designed for Linux operative system. There is the option to run brainflayer on Windows with WSL-Kali Linux. If you are interested in how to install and setup WSL-Kali on Windows click here.

The installation process of brainflayer on WSL-Kali is similar to normal Kali.

How to protect your brainwallet

The easiest way to protect yourself is by not using brainwallets. In case you still want to use one, then you must use a big complex random non-human generated seed as the input. Moreover, you have to ensure that the brainwallet is trusted and uses the best hashing algorithms (SHA256, SHA512 etc) multiple times to hash your seed.

Last but not least, users must never create or use a non-random bitcoin private key.

Btc brainflayer windows demo

Brainflayer is a Proof-of-Concept brainwallet cracking tool that uses libsecp256k1 for pubkey generation. It was originally released as part of my DEFCON talk about cracking brainwallets (slides, video, why).

The name is a reference to Mind Flayers, 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.

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.

Precompute the bloom filter:

hex2blf example.hex example.blf

Run Brainflayer against it:

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

your_generator | brainflayer -v -b example.blf

Brainflayer’s design is heavily influenced by 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, 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.

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

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.

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.

About

A proof-of-concept cracker for cryptocurrency brainwallets and other low entropy key alogrithms.