Nowadays, you do not have to worry too much about installing OpenSSL: most distributions use package management applications. Refer to your distribution documentation, or read the README and INSTALL file inside the OpenSSL tarball. I want also to avoid to make this HOWTO, an installation HOWTO rather than an HOWTO use certificates.
I describe here some standard installation options which are necessary to know for the samples following. Your installation may differ.
The directory for all OpenSSL certificates is /var/ssl/. All commands and paths in this document are issued from this directory, it is not mandatory but it will help the examples.
OpenSSL by default looks for a configuration file in /usr/lib/ssl/openssl.cnf so always add -config /etc/openssl.cnf to the commands openssl ca or openssl req for instance. I use /etc/openssl.cnf so all my configuration files are all in /etc.
Utilities and other libraries are located in /usr/lib/ssl.
Ensure that the utility CA.pl is in an accessible directory such as /usr/sbin. CA.pl can be found inside /usr/lib/ssl directories. CA.pl is a utility that hides the complexity of the openssl command. In all the examples, when I use CA.pl, I will also put the openssl equivalent in brakets.
/usr/sbin/CA.pl needs to be modified to include -config /etc/openssl.cnf in ca and req calls.
#$SSLEAY_CONFIG=$ENV{"SSLEAY_CONFIG"}
$SSLEAY_CONFIG="-config /etc/openssl.cnf";
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/etc/openssl.cnf must be configured accordingly to minimize input entry.
#---Begin---
#
# OpenSSL example configuration file.
# This is mostly being used for generation of certificate requests.
#
RANDFILE = $ENV::HOME/.rnd
oid_file = $ENV::HOME/.oid
oid_section = new_oids
# To use this configuration file with the "-extfile" option of the
# "openssl x509" utility, name here the section containing the
# X.509v3 extensions to use:
# extensions =
# (Alternatively, use a configuration file that has only
# X.509v3 extensions in its main [= default] section.)
[ new_oids ]
# We can add new OIDs in here for use by 'ca' and 'req'.
# Add a simple OID like this:
# testoid1=1.2.3.4
# Or use config file substitution like this:
# testoid2=${testoid1}.5.6
####################################################################
[ ca ]
default_ca = CA_default # The default ca section
####################################################################
[ CA_default ]
dir = /var/ssl # Where everything is kept
certs = $dir/certs # Where the issued certs are kept
crl_dir = $dir/crl # Where the issued crl are kept
database = $dir/index.txt # database index file.
new_certs_dir = $dir/newcerts # default place for new certs.
certificate = $dir/cacert.pem # The CA certificate
serial = $dir/serial # The current serial number
crl = $dir/crl.pem # The current CRL
private_key = $dir/private/cakey.pem # The private key
RANDFILE = $dir/private/.rand # private random number file
x509_extensions = usr_cert # The extentions to add to the cert
# Extensions to add to a CRL. Note: Netscape communicator chokes on V2 CRLs
# so this is commented out by default to leave a V1 CRL.
# crl_extensions = crl_ext
default_days = 365 # how long to certify for
default_crl_days= 30 # how long before next CRL
default_md = sha1 # which md to use.
preserve = no # keep passed DN ordering
# A few difference way of specifying how similar the request should look
# For type CA, the listed attributes must be the same, and the optional
# and supplied fields are just that :-)
policy = policy_match
# For the CA policy
[ policy_match ]
countryName = match
stateOrProvinceName = optional
localityName = match
organizationName = match
organizationalUnitName = optional
commonName = supplied
emailAddress = optional
# For the 'anything' policy
# At this point in time, you must list all acceptable 'object'
# types.
[ policy_anything ]
countryName = optional
stateOrProvinceName = optional
localityName = optional
organizationName = optional
organizationalUnitName = optional
commonName = supplied
emailAddress = optional
####################################################################
[ req ]
default_bits = 1024
default_keyfile = privkey.pem
distinguished_name = req_distinguished_name
attributes = req_attributes
default_md = sha1
x509_extensions = v3_ca # The extentions to add to the self signed cert
[ req_distinguished_name ]
countryName = Country Name (2 letter code)
countryName_default = FJ
countryName_min = 2
countryName_max = 2
stateOrProvinceName = State or Province Name (full name)
stateOrProvinceName_default = Fiji
localityName = Locality Name (eg, city)
localityName_default = Suva
0.organizationName = Organization Name (eg, company)
0.organizationName_default = SOPAC
# we can do this but it is not needed normally :-)
#1.organizationName = Second Organization Name (eg, company)
#1.organizationName_default = World Wide Web Pty Ltd
organizationalUnitName = Organizational Unit Name (eg, section)
organizationalUnitName_default = ITU
commonName = Common Name (eg, YOUR name)
commonName_max = 64
emailAddress = Email Address
emailAddress_max = 40
# SET-ex3 = SET extension number 3
[ req_attributes ]
challengePassword = A challenge password
challengePassword_min = 4
challengePassword_max = 20
unstructuredName = An optional company name
[ usr_cert ]
# These extensions are added when 'ca' signs a request.
# This goes against PKIX guidelines but some CAs do it and some software
# requires this to avoid interpreting an end user certificate as a CA.
basicConstraints=CA:FALSE
# Here are some examples of the usage of nsCertType. If it is omitted
# the certificate can be used for anything *except* object signing.
# This is OK for an SSL server.
# nsCertType = server
# For an object signing certificate this would be used.
# nsCertType = objsign
# For normal client use this is typical
# nsCertType = client, email
# and for everything including object signing:
# nsCertType = client, email, objsign
# This is typical in keyUsage for a client certificate.
# keyUsage = nonRepudiation, digitalSignature, keyEncipherment
# This will be displayed in Netscape's comment listbox.
nsComment = "Certificate issued by https://www.sopac.org/ssl/"
# PKIX recommendations harmless if included in all certificates.
subjectKeyIdentifier=hash
authorityKeyIdentifier=keyid,issuer:always
# This stuff is for subjectAltName and issuerAltname.
# Import the email address.
# subjectAltName=email:copy
# Copy subject details
# issuerAltName=issuer:copy
# This is the base URL for all others URL addresses
# if not supplied
nsBaseUrl = https://www.sopac.org/ssl/
# This is the link where to download the latest Certificate
# Revocation List (CRL)
nsCaRevocationUrl = https://www.sopac.org/ssl/sopac-ca.crl
# This is the link where to revoke the certificate
nsRevocationUrl = https://www.sopac.org/ssl/revocation.html?
# This is the location where the certificate can be renewed
nsRenewalUrl = https://www.sopac.org/ssl/renewal.html?
# This is the link where the CA policy can be found
nsCaPolicyUrl = https://www.sopac.org/ssl/policy.html
# This is the link where we can get the issuer certificate
issuerAltName = URI:https://www.sopac.org/ssl/sopac.crt
# This is the link where to get the latest CRL
crlDistributionPoints = URI:https://www.sopac.org/ssl/sopac-ca.crl
[ v3_ca ]
# Extensions for a typical CA
# PKIX recommendation.
subjectKeyIdentifier=hash
authorityKeyIdentifier=keyid:always,issuer:always
# This is what PKIX recommends but some broken software chokes on critical
# extensions.
# basicConstraints = critical,CA:true
# So we do this instead.
basicConstraints = CA:true
# Key usage: this is typical for a CA certificate. However since it will
# prevent it being used as an test self-signed certificate it is best
# left out by default.
# keyUsage = cRLSign, keyCertSign
# Some might want this also
# nsCertType = sslCA, emailCA
# Include email address in subject alt name: another PKIX recommendation
# subjectAltName=email:copy
# Copy issuer details
# issuerAltName=issuer:copy
# RAW DER hex encoding of an extension: beware experts only!
# 1.2.3.5=RAW:02:03
# You can even override a supported extension:
# basicConstraints= critical, RAW:30:03:01:01:FF
# This will be displayed in Netscape's comment listbox.
nsComment = "Certificate issued by https://www.sopac.org/ssl/"
# This is the base URL for all others URL addresses
# if not supplied
nsBaseUrl = https://www.sopac.org/ssl/
# This is the link where to download the latest Certificate
# Revocation List (CRL)
nsCaRevocationUrl = https://www.sopac.org/ssl/sopac-ca.crl
# This is the link where to revoke the certificate
nsRevocationUrl = https://www.sopac.org/ssl/revocation.html?
# This is the location where the certificate can be renewed
nsRenewalUrl = https://www.sopac.org/ssl/renewal.html?
# This is the link where the CA policy can be found
nsCaPolicyUrl = https://www.sopac.org/ssl/policy.html
# This is the link where we can get the issuer certificate
issuerAltName = URI:https://www.sopac.org/ssl/sopac.crt
# This is the link where to get the latest CRL
crlDistributionPoints = URI:https://www.sopac.org/ssl/sopac-ca.crl
[ crl_ext ]
# CRL extensions.
# Only issuerAltName and authorityKeyIdentifier make any sense in a CRL.
# issuerAltName=issuer:copy
authorityKeyIdentifier=keyid:always,issuer:always
#----End----
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A few comments on openssl.cnf.
Variable names can use the suffixes _default for default value, _min for the minimum number of characters required and _max for the maximum number of characters required.
The file is composed of [Sections] of variables.
Specifies the base directory.
Specifies which section contains the variables for a default certificate.
Defines the usage of the certificate, for instance with CA:TRUE, the certificate is a root CA Certificate.
To create a certification authority, use the command after correctly editing openssl.cnf:
CA.pl -newca |