Tutorial How to securely generate vanity addresses for others

[Tutorial] How to securely generate vanity addresses for others - Printable Version

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How to securely generate vanity addresses for others - XMR - Aug 27, 2016

Someone recently wrote a tutorial on how to generate addresses with custom prefixes, but that isn't secure for generating addresses for other people as both parties will have access to the private key. This tutorial will cover how to generate vanity addresses for other people in a manner such that only the recipient will have access to the final private key. For this, both parties will need the vanitygen tools.

I'm using an Arch Linux system for this tutorial, though you can download v0.22 pre-built Windows binaries from here: https://github.com/downloads/samr7/vanitygen/vanitygen-0.22-win.zip

Lines starting with '#' symbols are comments and can be ignored. If you type them into your shell, nothing will happen.

Download the vanitygen tools and navigate to the new directory:

Code 
arccot@arccotangent-arch:~$ git clone https://github.com/samr7/vanitygen.git && cd vanitygen

You could also download the repository (source code) as a zip file from here: https://github.com/samr7/vanitygen/archive/master.zip

If compiling from source, you will need to install the compiler and dependencies:

Code 
Debian/Ubuntu: sudo apt-get install build-essential git libssl-dev libpcre3-dev

Arch Linux: sudo pacman -S openssl pcre gcc git

# Arch doesn't have separate development packages, everything is packaged as one. There is no openssl-dev or pcre-dev.

Compile the tools:

Code 
arccot@arccotangent-arch:~/vanitygen$ make

Optionally, you can install the tools to /usr/local/bin:

Code 
arccot@arccotangent-arch:~/vanitygen$ sudo install vanitygen /usr/local/bin && sudo install keyconv /usr/local/bin

To generate a partial private key, you'll need the recipient's public key. They can generate a new address by performing this command:

Code 
user@recipient:~$ keyconv -G

Pubkey (hex): 0434c524119cc9cc2cec1a056ab6270c49be404360fe359b6ad820456ce30b6b93f01e961f287d6feec38dd7e589c2284f9b126c3b0a09fc8440765e944535fa29

Privkey (hex): D17113CB2FE050EA8402A0A31994D846C15E16D2225E1CA55CF8CECFBB377CEC

Address: 1LJ2vQX8rdUHk982VHoBxRxNYpceinJ3yH

Privkey: 5KQXVJjWmKHGLoXWTjeSZ2TzU1o7tBr5giVCruCWRrvKMdLkfyA

Code 
# Generate a new, random address

keyconv -G

Then they will need to send you the hexadecimal public key that starts with "04" and you can use this public key with the -P option to generate a partial private key:

Code 
arccot@arccotangent-arch:~/vanitygen$ vanitygen -P 0434c524119cc9cc2cec1a056ab6270c49be404360fe359b6ad820456ce30b6b93f01e961f287d6feec38dd7e589c2284f9b126c3b0a09fc8440765e944535fa29 1Tut

Difficulty: 4553521

Pattern: 1Tut                                                                  

Address: 1Tut5yHDrbtbHJWqG1NmHXLBpm2WtRTMk

PrivkeyPart: 5K2a9aDFyE3AHAwq1rpAWPUiVgr5KPxDHb2p9UZMD6ymiQsuBfW

Code 
# Generate a partial private key, given someone's public key

vanitygen -P <public key> <address prefix>

Finally, the recipient of the address can combine the private key from the address they generated, and the partial privkey (shown here as "PrivkeyPart") that the other person generated and get the private key for the vanity address:

Code 
user@recipient:~$ keyconv -c 5KQXVJjWmKHGLoXWTjeSZ2TzU1o7tBr5giVCruCWRrvKMdLkfyA 5K2a9aDFyE3AHAwq1rpAWPUiVgr5KPxDHb2p9UZMD6ymiQsuBfW

Address: 1Tut5yHDrbtbHJWqG1NmHXLBpm2WtRTMk

Privkey: 5Jg4sy3eof5DE9WMXpPi23btMrZTsmM7vZe7nujY6j4SB7Qr4UA

Code 
# Combine private key parts to get the vanity address private key

keyconv -c <private key 1> <private key 2>

The order in which the partial private keys are specified doesn't matter. The person that generated the partial private key has no access to your vanity address as the partial private key corresponds to a completely different address:

Code 
arccot@arccotangent-arch:~/vanitygen$ keyconv 5K2a9aDFyE3AHAwq1rpAWPUiVgr5KPxDHb2p9UZMD6ymiQsuBfW

Address: 1PWEtY6RK6UkPuUipKrZ7dESrWtRSey3Mn

Privkey: 5K2a9aDFyE3AHAwq1rpAWPUiVgr5KPxDHb2p9UZMD6ymiQsuBfW

Code 
# Get the address corresponding to a certain private key

keyconv <private key>

The person that generated the partial private key has no access to the vanity address, only the person that requested it has access to the final key. Therefore, it is possible to generate vanity addresses for others as a paid service. 🎉

* - Jаson - Aug 27, 2016

ayy lmao ok show off 🎉

* - Bαker - Aug 27, 2016

Does this work with only BTC?

* - minimalist - Aug 27, 2016

Nice write-up. I'm happy here with my non-vanity BTC address but this will probably come in handy to those who want to open up vanity gen services...because those are a thing.

* - XMR - Aug 27, 2016

(Aug 27, 2016 06:32 PM)Blаck Wrote: ayy lmao ok show off 🎉

It legitimately took me like 10 minutes to realize you wrote the other tut 🤣

(Aug 27, 2016 06:33 PM)๖ۣۜMrDark Wrote: Does this work with only BTC?

Technically, no. It can work with any cryptocurrency, but you'll need to modify the code accordingly for the different address/private key versions.

This article can be of help: https://en.bitcoin.it/wiki/List_of_address_prefixes