chore: checkpoint before Python removal

vendor/rcgen/examples/rsa-irc-openssl.rs

@@ -0,0 +1,43 @@
+#[cfg(unix)]
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+	use std::fmt::Write;
+	use std::fs;
+
+	use rcgen::{date_time_ymd, CertificateParams, DistinguishedName};
+
+	let mut params: CertificateParams = Default::default();
+	params.not_before = date_time_ymd(2021, 5, 19);
+	params.not_after = date_time_ymd(4096, 1, 1);
+	params.distinguished_name = DistinguishedName::new();
+
+	let pkey: openssl::pkey::PKey<_> = openssl::rsa::Rsa::generate(2048)?.try_into()?;
+	let key_pair_pem = String::from_utf8(pkey.private_key_to_pem_pkcs8()?)?;
+	let key_pair = rcgen::KeyPair::from_pem(&key_pair_pem)?;
+
+	let cert = params.self_signed(&key_pair)?;
+	let pem_serialized = cert.pem();
+	let pem = pem::parse(&pem_serialized)?;
+	let der_serialized = pem.contents();
+	let hash = ring::digest::digest(&ring::digest::SHA512, der_serialized);
+	let hash_hex = hash.as_ref().iter().fold(String::new(), |mut output, b| {
+		let _ = write!(output, "{b:02x}");
+		output
+	});
+	println!("sha-512 fingerprint: {hash_hex}");
+	println!("{pem_serialized}");
+	println!("{}", key_pair.serialize_pem());
+	std::fs::create_dir_all("certs/")?;
+	fs::write("certs/cert.pem", pem_serialized.as_bytes())?;
+	fs::write("certs/cert.der", der_serialized)?;
+	fs::write("certs/key.pem", key_pair.serialize_pem().as_bytes())?;
+	fs::write("certs/key.der", key_pair.serialize_der())?;
+	Ok(())
+}
+
+#[cfg(not(unix))]
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+	// Due to the support burden of running OpenSSL on Windows,
+	// we only support the OpenSSL backend on Unix-like systems.
+	// It should still work on Windows if you have OpenSSL installed.
+	unimplemented!("OpenSSL backend is not supported on Windows");
+}