To cite package ‘base64’ in publications use:

  Ooms J (2024). _base64: Base64 Encoder and Decoder_. R package
  version 2.0.2, <https://github.com/jeroen/base64>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {base64: Base64 Encoder and Decoder},
    author = {Jeroen Ooms},
    year = {2024},
    note = {R package version 2.0.2},
    url = {https://github.com/jeroen/base64},
  }