gnutls 生成证书

具体看man certtool，certtool可生成任意类型的密钥对和证书

https://help.ubuntu.com/community/GnuTLS?_ga=2.224769235.859107353.1621415949-904983128.1621415949

生成证书语句：

certtool --generate-certificate --load-privkey key.pem     --template cert.cfg --outfile cert.pem    --load-ca-certificate ca-cert.pem --load-ca-privkey ca-key.pem

证书模板：

           # X.509 Certificate options
           #
           # DN options

           # The organization of the subject.
           organization = "Koko inc."

           # The organizational unit of the subject.
           unit = "sleeping dept."

           # The locality of the subject.
           # locality =

           # The state of the certificate owner.
           state = "Attiki"

           # The country of the subject. Two letter code.
           country = CN

           # The common name of the certificate owner.
           cn = "Cindy Lauper"

           # A user id of the certificate owner.
           #uid = "clauper"

           # Set domain components
           #dc = "name"
           #dc = "domain"

           # If the supported DN OIDs are not adequate you can set
           # any OID here.
           # For example set the X.520 Title and the X.520 Pseudonym
           # by using OID and string pairs.
           #dn_oid = "2.5.4.12 Dr."
           #dn_oid = "2.5.4.65 jackal"

           # This is deprecated and should not be used in new
           # certificates.
           # pkcs9_email = "[e-mail]"

           # An alternative way to set the certificate's distinguished name directly
           # is with the "dn" option. The attribute names allowed are:
           # C (country), street, O (organization), OU (unit), title, CN (common name),
           # L (locality), ST (state), placeOfBirth, gender, countryOfCitizenship,
           # countryOfResidence, serialNumber, telephoneNumber, surName, initials,
           # generationQualifier, givenName, pseudonym, dnQualifier, postalCode, name,
           # businessCategory, DC, UID, jurisdictionOfIncorporationLocalityName,
           # jurisdictionOfIncorporationStateOrProvinceName,
           # jurisdictionOfIncorporationCountryName, XmppAddr, and numeric OIDs.

           #dn = "cn = Nikos,st = New Something,C=GR,surName=Mavrogiannopoulos,2.5.4.9=Arkadias"

           # The serial number of the certificate
           # The value is in decimal (i.e. 1963) or hex (i.e. 0x07ab).
           # Comment the field for a random serial number.
           serial = 007

           # In how many days, counting from today, this certificate will expire.
           # Use -1 if there is no expiration date.
           expiration_days = 700

           # Alternatively you may set concrete dates and time. The GNU date string
           # formats are accepted. See:
           # https://www.gnu.org/software/tar/manual/html_node/Date-input-formats.html

           #activation_date = "2004-02-29 16:21:42"
           #expiration_date = "2025-02-29 16:24:41"

           # X.509 v3 extensions

           # A dnsname in case of a WWW server.
           #dns_name = "www.none.org"
           #dns_name = "www.morethanone.org"

           # An othername defined by an OID and a hex encoded string
           #other_name = "1.3.6.1.5.2.2 302ca00d1b0b56414e5245494e2e4f5247a11b3019a006020400000002a10f300d1b047269636b1b0561646d696e"
           #other_name_utf8 = "1.2.4.5.6 A UTF8 string"
           #other_name_octet = "1.2.4.5.6 A string that will be encoded as ASN.1 octet string"

           # Allows writing an XmppAddr Identifier
           #xmpp_name = [e-mail]

           # Names used in PKINIT
           #krb5_principal = [e-mail]
           #krb5_principal = HTTP/[e-mail]

           # A subject alternative name URI
           #uri = "https://www.example.com"

           # An IP address in case of a server.
           #ip_address = "192.168.1.1"

           # An email in case of a person
           email = "[e-mail]"

           # TLS feature (rfc7633) extension. That can is used to indicate mandatory TLS
           # extension features to be provided by the server. In practice this is used
           # to require the Status Request (extid: 5) extension from the server. That is,
           # to require the server holding this certificate to provide a stapled OCSP response.
           # You can have multiple lines for multiple TLS features.

           # To ask for OCSP status request use:
           #tls_feature = 5

           # Challenge password used in certificate requests
           challenge_password = 123456

           # Password when encrypting a private key
           #password = secret

           # An URL that has CRLs (certificate revocation lists)
           # available. Needed in CA certificates.
           #crl_dist_points = "https://www.getcrl.crl/getcrl/"

           # Whether this is a CA certificate or not
           #ca

           # Subject Unique ID (in hex)
           #subject_unique_id = 00153224

           # Issuer Unique ID (in hex)
           #issuer_unique_id = 00153225

           #### Key usage

           # The following key usage flags are used by CAs and end certificates
           # to clarify its purpose. Some CAs also use it to indicate
           # the types of certificates they are purposed to sign.

           # Whether this certificate will be used for a TLS client;
           # this sets the id-kp-clientAuth (1.3.6.1.5.5.7.3.2) of
           # extended key usage.
           #tls_www_client

           # Whether this certificate will be used for a TLS server;
           # this sets the id-kp-serverAuth (1.3.6.1.5.5.7.3.1) of
           # extended key usage.
           #tls_www_server

           # Whether this key will be used to sign code. This sets the
           # id-kp-codeSigning (1.3.6.1.5.5.7.3.3) of extended key usage
           # extension.
           #code_signing_key

           # Whether this key will be used to sign OCSP data. This sets the
           # id-kp-OCSPSigning (1.3.6.1.5.5.7.3.9) of extended key usage extension.
           #ocsp_signing_key

           # Whether this key will be used for time stamping. This sets the
           # id-kp-timeStamping (1.3.6.1.5.5.7.3.8) of extended key usage extension.
           #time_stamping_key

           # Whether this key will be used for email protection. This sets the
           # id-kp-emailProtection (1.3.6.1.5.5.7.3.4) of extended key usage extension.
           #email_protection_key

           # Whether this key will be used for IPsec IKE operations (1.3.6.1.5.5.7.3.17).
           #ipsec_ike_key

           ## adding custom key purpose OIDs

           # for microsoft smart card logon
           # key_purpose_oid = 1.3.6.1.4.1.311.20.2.2

           # for email protection
           # key_purpose_oid = 1.3.6.1.5.5.7.3.4

           # for any purpose (must not be used in intermediate CA certificates)
           # key_purpose_oid = 2.5.29.37.0

           ### end of key purpose OIDs

           ### Adding arbitrary extensions
           # This requires to provide the extension OIDs, as well as the extension data in
           # hex format. The following two options are available since GnuTLS 3.5.3.
           #add_extension = "1.2.3.4 0x0AAB01ACFE"

           # As above but encode the data as an octet string
           #add_extension = "1.2.3.4 octet_string(0x0AAB01ACFE)"

           # For portability critical extensions shouldn't be set to certificates.
           #add_critical_extension = "5.6.7.8 0x1AAB01ACFE"

           # When generating a certificate from a certificate
           # request, then honor the extensions stored in the request
           # and store them in the real certificate.
           #honor_crq_extensions

           # Alternatively only specific extensions can be copied.
           #honor_crq_ext = 2.5.29.17
           #honor_crq_ext = 2.5.29.15

           # Path length constraint. Sets the maximum number of
           # certificates that can be used to certify this certificate.
           # (i.e. the certificate chain length)
           #path_len = -1
           #path_len = 2

           # OCSP URI
           # ocsp_uri = https://my.ocsp.server/ocsp

           # CA issuers URI
           # ca_issuers_uri = https://my.ca.issuer

           # Certificate policies
           #policy1 = 1.3.6.1.4.1.5484.1.10.99.1.0
           #policy1_txt = "This is a long policy to summarize"
           #policy1_url = https://www.example.com/a-policy-to-read

           #policy2 = 1.3.6.1.4.1.5484.1.10.99.1.1
           #policy2_txt = "This is a short policy"
           #policy2_url = https://www.example.com/another-policy-to-read

           # The number of additional certificates that may appear in a
           # path before the anyPolicy is no longer acceptable.
           #inhibit_anypolicy_skip_certs 1

           # Name constraints

           # DNS
           #nc_permit_dns = example.com
           #nc_exclude_dns = test.example.com

           # EMAIL
           #nc_permit_email = "[e-mail]"

           # Exclude subdomains of example.com
           #nc_exclude_email = .example.com

           # Exclude all e-mail addresses of example.com
           #nc_exclude_email = example.com

           # IP
           #nc_permit_ip = 192.168.0.0/16
           #nc_exclude_ip = 192.168.5.0/24
           #nc_permit_ip = fc0a:eef2:e7e7:a56e::/64

           # Options for proxy certificates
           #proxy_policy_language = 1.3.6.1.5.5.7.21.1

           # Options for generating a CRL

           # The number of days the next CRL update will be due.
           # next CRL update will be in 43 days
           #crl_next_update = 43

           # this is the 5th CRL by this CA
           # The value is in decimal (i.e. 1963) or hex (i.e. 0x07ab).
           # Comment the field for a time-based number.
           # Time-based CRL numbers generated in GnuTLS 3.6.3 and later
           # are significantly larger than those generated in previous
           # versions. Since CRL numbers need to be monotonic, you need
           # to specify the CRL number here manually if you intend to
           # downgrade to an earlier version than 3.6.3 after publishing
           # the CRL as it is not possible to specify CRL numbers greater
           # than 263-2 using hex notation in those versions.
           #crl_number = 5

           # Specify the update dates more precisely.
           #crl_this_update_date = "2004-02-29 16:21:42"
           #crl_next_update_date = "2025-02-29 16:24:41"

           # The date that the certificates will be made seen as
           # being revoked.
           #crl_revocation_date = "2025-02-29 16:24:41"