Handy simple tool for common certificate-related operations.

$ certainly test.example.com test2.example.com foo.local 10.0.200.36
Writing test.example.com.key
Writing test.example.com.crt

$ certainly --inspect test.example.com.crt
[Local]  C=ZZ, O=Certainly, OU=test.example.com from kaydel-ko, CN=test.example.com
Issuer:  C=ZZ, O=Certainly, OU=test.example.com from kaydel-ko, CN=test.example.com

Created on:   Sun Sep 15 01:30:14 2019
Expires on:   Sun Sep 15 01:30:14 2029

Domains:
 DNS: test.example.com
 DNS: test2.example.com
 DNS: foo.local
 IPV4: 10.0.200.36

To see more: $ openssl x509 -text -in test.example.com.crt

$ certainly --inspect twitter.com
[Remote] C=US, ST=California, L=San Francisco, O=Twitter, Inc., OU=syd2, CN=twitter.com
Issuer:  C=US, O=DigiCert Inc, OU=www.digicert.com, CN=DigiCert SHA2 High Assurance Server CA

Chain:
 Subject: C=US, O=DigiCert Inc, OU=www.digicert.com, CN=DigiCert SHA2 High Assurance Server CA
 Issuer:  C=US, O=DigiCert Inc, OU=www.digicert.com, CN=DigiCert High Assurance EV Root CA

Created on:   Sun May 13 00:00:00 2019
Expires on:   Sun May 10 12:00:00 2020

Domains:
 DNS: twitter.com
 DNS: www.twitter.com

To see more: $ echo Q | openssl s_client twitter.com:443

Binaries are available through GitHub Releases.

With Cargo: cargo install certainly

yay -S certainly-bin

Download the deb file from GitHub Releases.

Accepting contributions for more!

This project uses Caretaker Maintainership.

• --std and --reverse-std will output both key and certificate to STDOUT instead of writing files.

• --double-std will output the key to STDERR and the certificate to STDOUT instead, so redirection can be used to write or pipe files where needed efficiently. Take care of checking the key is actually formatted properly and not an error message though!

• --inspect outputs terse information about the passed certificate file (or url) and exits.

• --make-ca creates a key/certificate pair suitable for issuing instead. Use with --ca.

• --ca NAME signs a certificate with a CA pair instead of self-signing. Provide only the common filename, without the .crt and .key extensions.

• --client creates client certificates rather than server ones.

• --ecdsa creates p256r1 ECDSA certificates (default).

• --ed25519 creates ED25519 certificates.

• --rsa creates 4096-bit RSA certificates (not for production use).

See the man page for more.

• mkcert, a tool specifically for local-CA certificate management.

• Copyright © Félix Saparelli.
• Licensed under the Artistic License 2.0.