CFSSL
Cloudflare's PKI and TLS toolkit
... cross compile for alternative platforms; however, cfssl requires cgo, and cgo requires a working compiler toolchain for the target platform. The csr is the client's certificate request. The -ca and -ca-key flags are the CA's certificate and private key, respectively. By default, they are ca.pem and ca_key.pem. The -hostname is a comma separated hostname list that overrides the DNS names and IP address in the certificate SAN extension.