In his guide "How to create your customized Bitcoin-Address (vanitygen) – step by step" 1miau already explained how to create a "Custom" Bitcoin address using vanitygen.

Examples (BTC):

1fudCz15sHGR8L2YQnaG4JVMjMQpaDo37
1BTCTUnYLskK7N9nXb17wf6oVYMYrX5WHG
1DogemNVw8AZnMf3cB4L1wijGnr9DVKzia
1Fomo7V86nWrjdv6JzU7yavtp5hfzZWsZr

Source: https://bitcointalk.org/index.php?topic=5096373.0

However generating such a custom address does not only work for Bitcoin, but also for Ethereum.

Bitcoin addresses are Base58 encoded and can contain the following characters:

1 2 3 4 5 6 7 8 9 a b c d e f g h i j k m n o p q r s t u v w x y z A B C D E F G H J K L M N P Q R S T U V W X Y Z

When creating our Ethereum address, we unfortunately have to limit ourselves to the hexadecimal system with the following characters:

0 1 2 3 4 5 6 7 8 9 A B C D E F

A few examples of custom ETH-addresses:
0xcafebabeb69f2361cec1106cb26e3f422b65442f
0xdeadbeef36072d66d93b2c9fda370c06964262b2
0xbadc0dedf5b784a70bc9a8c8476b5c88e9f6f49e
0x11111111262b236c9ac9a9a8c8e4276b5cf6b2c9

Example of "Hexspeak":
https://en.wikipedia.org/wiki/Hexspeak


For creating our desired address, we'll need some computing power and the time it takes to score a hit increases with the length of our prefix.

Available Tools:

VanityEth
- only uses CPU (-> slow)
- only available for Linux
- Open Source
- trustworthy source
https://github.com/MyEtherWallet/VanityEth

profanity
- uses GPU (-> much faster)
- Windows/Linux
- Open Source
https://github.com/johguse/profanity

vanity-eth.tk (online, therefore not recommended) [1]
- only uses CPU (-> slow)
- browser-based
- Open Source
https://github.com/bokub/vanity-eth


In this guide I will focus on creating a custom ETH-address utilizing our CPU using "VanityEth" - if you've got a GPU you might also want to check out my [Guide] on how to create an Ethereum custom-adress utilizing your GPU

_____________________________________________________

Prerequisites:
- Node.js
https://nodejs.org/en/download/
Windows Installer (.msi) [32- or 64bit depending on your OS]
_____________________________________________________

First we need the current source code of VanityEth, which can be found at the following link:
https://github.com/MyEtherWallet/VanityEth

Navigate to "Clone or download" and click "Download ZIP".



Extract the content of the "VanityEth-master.zip" to your C:\ partition..

Now we start a command prompt by entering "CMD" in the Windows search or open the run dialog box by pressing the [WINDOWS] + [R] key at the same time and start the command prompt by entering "CMD".



Run the following commands to switch to the folder containing the contents of our previously extracted .zip-file followed and installing the VanityEth-Package using npm.

cd C:\VanityEth-master npm install

We're ready to start generating our address (I'd recommend disconnecting your internet connection first).
Assuming we'd like to have an address starting with the prefix  "0xDEAD" (e.g. 0xDEADxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx), we'll have to use the following command:

  node index.js -i dead -l

As soon as a matching address has been found, it will be saved to a text-file with the corresponding private-key.
You can find the text-file in the VanityEth-master folder on your C:\-drive ( C:\VanityEth-master\"VanityEth-log-[...].txt)  [2][3].

Syntax:

Usage: node index.js <command> [options]

Options:
  -i, --input     input hex string                                      [string]
  -c, --checksum  check against the checksum address                   [boolean]
  -n, --count     number of wallets                                     [number]
  --contract      contract address for contract deployment             [boolean]
  -l, --log       log output to file                                   [boolean]
  -h, --help      Show help                                            [boolean]

Examples:
  node index.js -checksum -i B00B5  get a wallet where address matches B00B5 in
                               checksum format
  node index.js --contract -i ABC   get a wallet where 0 nonce contract address
                               matches the vanity
  node index.js -n 25 -i ABC        get 25 vanity wallets
  node index.js -n 1000             get 1000 random wallets

copyright 2018

If you have any questions please feel free to ask anytime. 

_____________________________________________________
[1] I didn't go into vanity-eth.tk in detail, but according to its Github it can also be used offline:

Once the web page is loaded, you can turn off the internet and continue playing, it will work seamlessly
You can also download the latest build of Vanity-ETH here and use it on a completely offline computer
The code is 100% open source and available on Github. You can review it as much as you want before using it

Source: https://github.com/bokub/vanity-eth

[2] [MyEtherWallet] Creating a (new) keystore-file using your private-key 
[3] [Guide] MyEtherWallet Offline Transactions [SECURITY]

© Nestade (=xuNsh1ne) 22.04.2019