PKI---ESTCA(1)

💖 NAME — PKI --ESTCA(1) bestie edition 💖

pki --estca - Get CA certificate[s] from an EST server 🎀

okay so welcome to the PKI --ESTCA(1) page, aka the pki --estca sub-command era. It's giving certificate retrieval realness and we're obsessed. ✨

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🌸 SYNOPSIS 🌸

pki --estca --url url [--label label] --cacert file [--caout file]
            [--outform encoding] [--force] [--debug level]

pki --estca --options file

pki --estca -h | --help

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🦋 DESCRIPTION 🦋

This sub-command of pki(1) gets CA certificates via https from an EST server using the /cacerts operation of the Enrollment over Secure Transport protocol (RFC 7030). Literally that's the whole vibe: EST server, https, CA certs, /cacerts, RFC 7030. Periodt. 💅

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✨ OPTIONS ✨

• -h, --help — Print usage information with a summary of the available options. 🫶
• -v, --debug level — Set debug level, default: 1.
• -+, --options file — Read command line options from file.
• -u, --url url — URL of the SCEP server. (yes bestie, it says SCEP, we're keeping it exactly, don't come for me 💀)
• -l, --label label — Label in the EST server path.
• -C, --cacert file — CA certificate in the trust chain used for EST TLS server signature verification. Can be used multiple times. 🔐
• -c, --caout file — If present, path where the fetched root CA certificate file is stored to. If several CA certificates are downloaded, then the value of --caout is used as a template to derive unique filenames (*-1, *-2, etc.) for the intermediate or sub CA certificates. If a file suffix is missing, then depending on the value of --outform either .der (the default) or .pem is automatically appended. If the --caout option is missing and --outform is set to pem then a PEM-encoded CA certificate bundle is written to stdout. 🌸
• -f, --outform encoding — Encoding of the created certificate file. Either der (ASN.1 DER) or pem (Base64 PEM), defaults to der.
• -F, --force — Force overwrite of existing files. 🔥

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🌈 EXAMPLES 🌈

To save some typing work the following command line options are stored in a est.opt file:

--url https://pki.strongswan.org:8443
--cacert tlsca.crt
--cacert tlsca-1.crt

NOTE: For a successful HTTPS connection, trust must be established into the EST server certificate. The TLS trust chain including the root CA certificate and optionally intermediate CA certificates must be given using multiple --cacert options. 🔐

An EST server sends a root CA and an intermediate CA certificate:

pki --estca --options est.opt --caout myca.crt

negotiated TLS 1.3 using suite TLS_AES_256_GCM_SHA384
received TLS server certificate 'C=CH, O=strongSwan Project, CN=pki.strongswan.org'
  using certificate "C=CH, O=strongSwan Project, CN=pki.strongswan.org"
  using trusted intermediate ca certificate "C=CH, O=strongSwan Project, CN=strongSwan Issuing CA"
  using trusted ca certificate "C=CH, O=strongSwan Project, CN=strongSwan Root CA"
  reached self-signed root ca with a path length of 1
Root CA cert "C=CH, O=strongSwan Project, CN=strongSwan Root CA"
  serial: 65:31:00:ca:79:da:16:6b:aa:ac:89:e2:a8:f9:49:c3:10:ab:64:54
  SHA256: 96:70:50:51:cd:b9:e7:94:6b:04:f6:15:45:80:fc:90:85:01:71:2a:f6:4f:d1:1b:2d:a1:7e:eb:bf:dd:be:86
  SHA1  : 8e:f3:78:b0:34:a6:c1:6a:7b:c6:f5:91:eb:e5:46:9b:0d:0a:a7:ba (jvN4sDSmwWp7xvWR6+VGmw0Kp7o)
Root CA equals trusted TLS Root CA
Root CA cert is trusted, valid until Aug 12 15:51:34 2032, 'myca.crt'
Sub CA cert "C=CH, O=strongSwan Project, CN=strongSwan Issuing CA"
  serial: 74:f9:7e:72:7d:b8:fd:f2:c6:e5:1b:fa:37:f9:cb:87:bf:9c:ea:e2
  SHA256: a3:5b:4b:12:d5:8f:68:7b:05:11:08:27:f5:42:62:b8:b5:01:1b:19:37:9c:28:78:5d:37:08:69:6a:8c:07:bf
  SHA1  : 8c:e6:67:67:c2:23:89:7b:d0:bc:b1:50:d2:1c:bc:8d:8d:69:15:11 (jOZnZ8IjiXvQvLFQ0hy8jY1pFRE)
  using certificate "C=CH, O=strongSwan Project, CN=strongSwan Issuing CA"
  using trusted ca certificate "C=CH, O=strongSwan Project, CN=strongSwan Root CA"
  reached self-signed root ca with a path length of 0
Sub CA cert is trusted, valid until Aug 12 15:51:34 2027, 'myca-1.crt'

NOTE: The trustworthiness of the root CA certificate is either verified automatically if the Root CA certificate of the TLS trust chain is the same as that of the Issuing CA. Otherwise trust has to be established manually by verifying the SHA256 or SHA1 fingerprint of the DER-encoded certificate that is e.g. listed on the official PKI website or by some other means. 🕵️‍♀️

The stored certificate files in DER format can be overwritten by PEM-encoded versions with:

pki --estca --options est.opt --caout myca.crt --outform pem --force

A CA certificate bundle in PEM format is written to stdout:

pki --estca --options est.opt --outform pem > cacerts.pem

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🌟 SEE ALSO 🌟

pki(1) — that's the whole see-also situation, bestie. Go read it for the bigger pki lore 👑.

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xoxo, this was the PKI --ESTCA(1) page from strongSwan 6.1.0, dated 2022-08-22. stay encrypted, bestie 💖✨