This tool generates valid RSA keypairs which contain some piece of text. The details are discussed in the accompanying blog post.

Use

Simplest usage: python3 vanity_rsa.py "MyVanityText"

usage: vanity_rsa.py [-h] [--key-length KEY_LENGTH] [--key-format {PEM,SSH}]
                     [--output-file OUTPUT_FILE]
                     [--output-file-public OUTPUT_FILE_PUBLIC]
                     vanity

Generate an RSA key containing arbitrary text in the public key.

positional arguments:
  vanity                The text to inject

optional arguments:
  -h, --help            show this help message and exit
  --key-length KEY_LENGTH
                        The length of the key in bits
  --key-format {PEM,SSH}
                        The format of the key
  --output-file OUTPUT_FILE
                        Where to save the private key
  --output-file-public OUTPUT_FILE_PUBLIC
                        Where to save the public key

Dependencies

The code depends on cryptography package. While not strictly necessary, you may want to install gmpy2 for a factor 10 speedup. You can install both of these using pip install cryptography gmpy2.