Small command-line tools for making certificates with OCaml x509/nocrypto toolstack.
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A very small utility for making self-signed certificates and private keys using ocaml-x509 and ocaml-nocrypto for key generation. Intended as a (non-drop-in) replacement for these uses of the command-line openssl utility.


certify is now available in opam, a free source-based package manager for OCaml. You can install certify via opam with opam install certify.

Outside of opam:

git clone
cd ocaml-certify
ocaml pkg/ build

Binaries will be in _build/src, and you can install them wherever you like, or just use them in place.


For help, try selfsign --help, sign --help, or csr --help.

  • selfsign produces a private key and self-signed certificate
  • sign takes a certificate signing request, and a CA (key and certificate), and produces a certificate
  • csr produces a private key and a certificate signing request


Simple openssl interoperability tests are in tests/