CA

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CA
WhitespaceLogo.gif
What:
0x20 Certificate Authority CA
Participants:
Jaroslov
Locations:
Whitespace
Cornify

0x20 Certificate Authority

  • CA with OpenSSL
    • all flat files in 1 directory
    • can easily be stored/transported on an encrypted filesystem
  • Used for OpenVPN authentication

openssl.cnf

Check the openssl.cnf file with the 0x20 specific values:

  • root ca is valid for 15 years
  • certificates are valid for 5 years
  • DN: C=BE, ST=Ghent, L=Whitespace, O=0x20, CN=0x20 root ca
  • nsCaRevocationUrl = http://www.0x20.be/ca-0x20-crl.pem
  • extendedKeyUsage=serverAuth (server certs)
  • extendedKeyUsage=clientAuth (client certs)

Create a CA

$ openssl req -new -x509 -days 5475 -newkey rsa:4096 -extensions v3_ca -keyout \ 
private/ca-0x20-key.pem -out ca-0x20-cert.pem -config ./openssl.cnf

Sign server cert

  • Change openssl.cnf to server settings:
$ vi ./openssl.cnf
nsCertType = server
extendedKeyUsage=serverAuth
  • If needed create the key and the csr (certificate signing request):
$ openssl genrsa -aes256 -out 0x20-servername.key 2048
$ openssl req -new -key 0x20-servername.key -nodes -out 0x20-servername.csr
  • Sign the certificate:
$ openssl ca -in 0x20-servername.csr -cert ca-0x20-cert.pem -keyfile \
 private/ca-0x20-key.pem -out 0x20-servername.cert -config ./openssl.cnf
  • check index.txt (= the CA db)

Create a CRL

$ openssl ca -gencrl -out crl/crl.pem -config ./openssl.cnf
  • (first time you need to populate the crlnumber file: $ echo "01" > crlnumber)

Revoke a certificate

  • Check the certificates in newcerts/
  • Revoke the needed one:
$ openssl ca -revoke newcerts/1000.pem -config ./openssl.cnf
  • distribute the crl where needed.