Invoking certtool
-----------------

Tool to parse and generate X.509 certificates, requests and private keys. It can be used interactively or non interactively by specifying the template command line option.

The tool accepts files or supported URIs via the --infile option. In case PIN is required for URI access you can provide it using the environment variables GNUTLS_PIN and GNUTLS_SO_PIN.

This section was generated by AutoGen, using the agtexi-cmd template and the option descriptions for the certtool program. This software is released under the GNU General Public License, version 3 or later.

certtool help/usage (--help)
............................

This is the automatically generated usage text for certtool.

The text printed is the same whether selected with the help option (--help) or the more-help option (--more-help).  more-help will print the usage text by passing it through a pager program. more-help is disabled on platforms without a working fork(2) function.  The PAGER environment variable is used to select the program, defaulting to more.  Both will exit with a status code of 0.

     certtool - GnuTLS certificate tool
     Usage:  certtool [ -<flag> [<val>] | --<name>[{=| }<val>] ]...

        -d, --debug=num            Enable debugging
                                     - it must be in the range:
                                       0 to 9999
        -V, --verbose              More verbose output
                                     - may appear multiple times
            --infile=file          Input file
                                     - file must pre-exist
            --outfile=str          Output file

     Certificate related options:

        -i, --certificate-info     Print information on the given certificate
            --pubkey-info          Print information on a public key
        -s, --generate-self-signed  Generate a self-signed certificate
        -c, --generate-certificate  Generate a signed certificate
            --generate-proxy       Generates a proxy certificate
        -u, --update-certificate   Update a signed certificate
            --fingerprint          Print the fingerprint of the given certificate
            --key-id               Print the key ID of the given certificate
            --certificate-pubkey   Print certificate's public key
            --v1                   Generate an X.509 version 1 certificate (with no extensions)
            --sign-params=str      Sign a certificate with a specific signature algorithm

     Certificate request related options:

            --crq-info             Print information on the given certificate request
        -q, --generate-request     Generate a PKCS #10 certificate request
                                     - prohibits the option 'infile'
            --no-crq-extensions    Do not use extensions in certificate requests

     PKCS#12 file related options:

            --p12-info             Print information on a PKCS #12 structure
            --p12-name=str         The PKCS #12 friendly name to use
            --to-p12               Generate a PKCS #12 structure

     Private key related options:

        -k, --key-info             Print information on a private key
            --p8-info              Print information on a PKCS #8 structure
            --to-rsa               Convert an RSA-PSS key to raw RSA format
        -p, --generate-privkey     Generate a private key
            --bits=num             Specify the number of bits for key generation
            --curve=str            Specify the curve used for EC key generation
            --sec-param=str        Specify the security level [low, legacy, medium, high, ultra]
            --to-p8                Convert a given key to a PKCS #8 structure
        -8, --pkcs8                Use PKCS #8 format for private keys
            --provable             Generate a private key or parameters from a seed using a provable method
            --verify-provable-privkey  Verify a private key generated from a seed using a provable method
            --seed=str             When generating a private key use the given hex-encoded seed

     CRL related options:

        -l, --crl-info             Print information on the given CRL structure
            --generate-crl         Generate a CRL
            --verify-crl           Verify a Certificate Revocation List using a trusted list
                                     - requires the option 'load-ca-certificate'

     Certificate verification related options:

        -e, --verify-chain         Verify a PEM encoded certificate chain
            --verify               Verify a PEM encoded certificate (chain) against a trusted set
            --verify-hostname=str  Specify a hostname to be used for certificate chain verification
            --verify-email=str     Specify a email to be used for certificate chain verification
                                     - prohibits the option 'verify-hostname'
            --verify-purpose=str   Specify a purpose OID to be used for certificate chain verification
            --verify-allow-broken  Allow broken algorithms, such as MD5 for verification

     PKCS#7 structure options:

            --p7-generate          Generate a PKCS #7 structure
            --p7-sign              Signs using a PKCS #7 structure
            --p7-detached-sign     Signs using a detached PKCS #7 structure
            --p7-include-cert      The signer's certificate will be included in the cert list.
                                     - disabled as '--no-p7-include-cert'
                                     - enabled by default
            --p7-time              Will include a timestamp in the PKCS #7 structure
                                     - disabled as '--no-p7-time'
            --p7-show-data         Will show the embedded data in the PKCS #7 structure
                                     - disabled as '--no-p7-show-data'
            --p7-info              Print information on a PKCS #7 structure
            --p7-verify            Verify the provided PKCS #7 structure
            --smime-to-p7          Convert S/MIME to PKCS #7 structure

     Other options:

            --get-dh-params        List the included PKCS #3 encoded Diffie-Hellman parameters
            --dh-info              Print information PKCS #3 encoded Diffie-Hellman parameters
            --load-privkey=str     Loads a private key file
            --load-pubkey=str      Loads a public key file
            --load-request=str     Loads a certificate request file
            --load-certificate=str Loads a certificate file
            --load-ca-privkey=str  Loads the certificate authority's private key file
            --load-ca-certificate=str Loads the certificate authority's certificate file
            --load-crl=str         Loads the provided CRL
            --load-data=str        Loads auxiliary data
            --password=str         Password to use
            --null-password        Enforce a NULL password
            --empty-password       Enforce an empty password
            --hex-numbers          Print big number in an easier format to parse
            --cprint               In certain operations it prints the information in C-friendly format
            --key-type=str         Specify the key type to use on key generation
            --hash=str             Hash algorithm to use for signing
            --salt-size=num        Specify the RSA-PSS key default salt size
            --inder                Use DER format for input certificates, private keys, and DH parameters
                                     - disabled as '--no-inder'
            --inraw                an alias for the 'inder' option
            --outder               Use DER format for output certificates, private keys, and DH parameters
                                     - disabled as '--no-outder'
            --outraw               an alias for the 'outder' option
            --template=str         Template file to use for non-interactive operation
            --stdout-info          Print information to stdout instead of stderr
            --ask-pass             Enable interaction for entering password when in batch mode.
            --pkcs-cipher=str      Cipher to use for PKCS #8 and #12 operations
            --provider=str         Specify the PKCS #11 provider library

     Version, usage and configuration options:

        -v, --version[=arg]        output version information and exit
        -h, --help                 display extended usage information and exit
        -!, --more-help            extended usage information passed thru pager

     Options are specified by doubled hyphens and their name or by a single
     hyphen and the flag character.

     Tool to parse and generate X.509 certificates, requests and private keys.
     It can be used interactively or non interactively by specifying the
     template command line option.

     The tool accepts files or supported URIs via the --infile option.  In case
     PIN is required for URI access you can provide it using the environment
     variables GNUTLS_PIN and GNUTLS_SO_PIN.

Base options
............

debug option (-d).
..................

This is the ``enable debugging'' option. This option takes a number argument. Specifies the debug level.

cert-options options
....................

Certificate related options.

pubkey-info option.
...................

This is the ``print information on a public key'' option. The option combined with --load-request, --load-pubkey, --load-privkey and --load-certificate will extract the public key of the object in question.

fingerprint option.
...................

This is the ``print the fingerprint of the given certificate'' option. This is a simple hash of the DER encoding of the certificate. It can be combined with the --hash parameter. However, it is recommended for identification to use the key-id which depends only on the certificate's key.

key-id option.
..............

This is the ``print the key id of the given certificate'' option. This is a hash of the public key of the given certificate. It identifies the key uniquely, remains the same on a certificate renewal and depends only on signed fields of the certificate.

sign-params option.
...................

This is the ``sign a certificate with a specific signature algorithm'' option. This option takes a string argument. This option can be combined with --generate-certificate, to sign the certificate with a specific signature algorithm variant. The only option supported is 'RSA-PSS', and should be specified when the signer does not have a certificate which is marked for RSA-PSS use only.

crq-options options
...................

Certificate request related options.

generate-request option (-q).
.............................

This is the ``generate a pkcs #10 certificate request'' option.

This option has some usage constraints.  It:

  * must not appear in combination with any of the following options: infile.

Will generate a PKCS #10 certificate request. To specify a private key use --load-privkey.

pkcs12-options options
......................

PKCS#12 file related options.

p12-info option.
................

This is the ``print information on a pkcs #12 structure'' option. This option will dump the contents and print the metadata of the provided PKCS #12 structure.

p12-name option.
................

This is the ``the pkcs #12 friendly name to use'' option. This option takes a string argument. The name to be used for the primary certificate and private key in a PKCS #12 file.

to-p12 option.
..............

This is the ``generate a pkcs #12 structure'' option. It requires a certificate, a private key and possibly a CA certificate to be specified.

key-options options
...................

Private key related options.

p8-info option.
...............

This is the ``print information on a pkcs #8 structure'' option. This option will print information about encrypted PKCS #8 structures. That option does not require the decryption of the structure.

to-rsa option.
..............

This is the ``convert an rsa-pss key to raw rsa format'' option. It requires an RSA-PSS key as input and will output a raw RSA key. This command is necessary for compatibility with applications that cannot read RSA-PSS keys.

generate-privkey option (-p).
.............................

This is the ``generate a private key'' option. When generating RSA-PSS private keys, the --hash option will restrict the allowed hash for the key; in the same keys the --salt-size option is also acceptable.

curve option.
.............

This is the ``specify the curve used for ec key generation'' option. This option takes a string argument. Supported values are secp192r1, secp224r1, secp256r1, secp384r1 and secp521r1.

sec-param option.
.................

This is the ``specify the security level [low, legacy, medium, high, ultra]'' option. This option takes a string argument Security parameter. This is alternative to the bits option.

to-p8 option.
.............

This is the ``convert a given key to a pkcs #8 structure'' option. This needs to be combined with --load-privkey.

provable option.
................

This is the ``generate a private key or parameters from a seed using a provable method'' option. This will use the FIPS PUB186-4 algorithms (i.e., Shawe-Taylor) for provable key generation. When specified the private keys or parameters will be generated from a seed, and can be later validated with --verify-provable-privkey to be correctly generated from the seed. You may specify --seed or allow GnuTLS to generate one (recommended). This option can be combined with --generate-privkey or --generate-dh-params.

That option applies to RSA and DSA keys. On the DSA keys the PQG parameters are generated using the seed, and on RSA the two primes.

verify-provable-privkey option.
...............................

This is the ``verify a private key generated from a seed using a provable method'' option. This will use the FIPS-186-4 algorithms for provable key generation. You may specify --seed or use the seed stored in the private key structure.

seed option.
............

This is the ``when generating a private key use the given hex-encoded seed'' option. This option takes a string argument. The seed acts as a security parameter for the private key, and thus a seed size which corresponds to the security level of the private key should be provided (e.g., 256-bits seed).

crl-options options
...................

CRL related options.

generate-crl option.
....................

This is the ``generate a crl'' option. This option generates a Certificate Revocation List. When combined with --load-crl it would use the loaded CRL as base for the generated (i.e., all revoked certificates in the base will be copied to the new CRL).

verify-crl option.
..................

This is the ``verify a certificate revocation list using a trusted list'' option.

This option has some usage constraints.  It:

  * must appear in combination with the following options: load-ca-certificate.

The trusted certificate list must be loaded with --load-ca-certificate.

cert-verify-options options
...........................

Certificate verification related options.

verify-chain option (-e).
.........................

This is the ``verify a pem encoded certificate chain'' option. Verifies the validity of a certificate chain. That is, an ordered set of certificates where each one is the issuer of the previous, and the first is the end-certificate to be validated. In a proper chain the last certificate is a self signed one. It can be combined with --verify-purpose or --verify-hostname.

verify option.
..............

This is the ``verify a pem encoded certificate (chain) against a trusted set'' option. The trusted certificate list can be loaded with --load-ca-certificate. If no certificate list is provided, then the system's trusted certificate list is used. Note that during verification multiple paths may be explored. On a successful verification the successful path will be the last one. It can be combined with --verify-purpose or --verify-hostname.

verify-hostname option.
.......................

This is the ``specify a hostname to be used for certificate chain verification'' option. This option takes a string argument. This is to be combined with one of the verify certificate options.

verify-email option.
....................

This is the ``specify a email to be used for certificate chain verification'' option. This option takes a string argument.

This option has some usage constraints.  It:

  * must not appear in combination with any of the following options: verify-hostname.

This is to be combined with one of the verify certificate options.

verify-purpose option.
......................

This is the ``specify a purpose oid to be used for certificate chain verification'' option. This option takes a string argument. This object identifier restricts the purpose of the certificates to be verified. Example purposes are 1.3.6.1.5.5.7.3.1 (TLS WWW), 1.3.6.1.5.5.7.3.4 (EMAIL) etc. Note that a CA certificate without a purpose set (extended key usage) is valid for any purpose.

verify-allow-broken option.
...........................

This is the ``allow broken algorithms, such as md5 for verification'' option. This can be combined with --p7-verify, --verify or --verify-chain.

pkcs7-options options
.....................

PKCS#7 structure options.

p7-generate option.
...................

This is the ``generate a pkcs #7 structure'' option. This option generates a PKCS #7 certificate container structure. To add certificates in the structure use --load-certificate and --load-crl.

p7-sign option.
...............

This is the ``signs using a pkcs #7 structure'' option. This option generates a PKCS #7 structure containing a signature for the provided data from infile. The data are stored within the structure. The signer certificate has to be specified using --load-certificate and --load-privkey. The input to --load-certificate can be a list of certificates. In case of a list, the first certificate is used for signing and the other certificates are included in the structure.

p7-detached-sign option.
........................

This is the ``signs using a detached pkcs #7 structure'' option. This option generates a PKCS #7 structure containing a signature for the provided data from infile. The signer certificate has to be specified using --load-certificate and --load-privkey. The input to --load-certificate can be a list of certificates. In case of a list, the first certificate is used for signing and the other certificates are included in the structure.

p7-include-cert option.
.......................

This is the ``the signer's certificate will be included in the cert list.'' option.

This option has some usage constraints.  It:

  * can be disabled with --no-p7-include-cert.

  * It is enabled by default.

This options works with --p7-sign or --p7-detached-sign and will include or exclude the signer's certificate into the generated signature.

p7-time option.
...............

This is the ``will include a timestamp in the pkcs #7 structure'' option.

This option has some usage constraints.  It:

  * can be disabled with --no-p7-time.

This option will include a timestamp in the generated signature

p7-show-data option.
....................

This is the ``will show the embedded data in the pkcs #7 structure'' option.

This option has some usage constraints.  It:

  * can be disabled with --no-p7-show-data.

This option can be combined with --p7-verify or --p7-info and will display the embedded signed data in the PKCS #7 structure.

p7-verify option.
.................

This is the ``verify the provided pkcs #7 structure'' option. This option verifies the signed PKCS #7 structure. The certificate list to use for verification can be specified with --load-ca-certificate. When no certificate list is provided, then the system's certificate list is used. Alternatively a direct signer can be provided using --load-certificate. A key purpose can be enforced with the --verify-purpose option, and the --load-data option will utilize detached data.

other-options options
.....................

Other options.

generate-dh-params option.
..........................

This is the ``generate pkcs #3 encoded diffie-hellman parameters'' option. The will generate random parameters to be used with Diffie-Hellman key exchange. The output parameters will be in PKCS #3 format. Note that it is recommended to use the --get-dh-params option instead.

NOTE: THIS OPTION IS DEPRECATED

get-dh-params option.
.....................

This is the ``list the included pkcs #3 encoded diffie-hellman parameters'' option. Returns stored DH parameters in GnuTLS. Those parameters returned are defined in RFC7919, and can be considered standard parameters for a TLS key exchange. This option is provided for old applications which require DH parameters to be specified; modern GnuTLS applications should not require them.

load-privkey option.
....................

This is the ``loads a private key file'' option. This option takes a string argument. This can be either a file or a PKCS #11 URL

load-pubkey option.
...................

This is the ``loads a public key file'' option. This option takes a string argument. This can be either a file or a PKCS #11 URL

load-request option.
....................

This is the ``loads a certificate request file'' option. This option takes a string argument. This option can be used with a file

load-certificate option.
........................

This is the ``loads a certificate file'' option. This option takes a string argument. This option can be used with a file

load-ca-privkey option.
.......................

This is the ``loads the certificate authority's private key file'' option. This option takes a string argument. This can be either a file or a PKCS #11 URL

load-ca-certificate option.
...........................

This is the ``loads the certificate authority's certificate file'' option. This option takes a string argument. This can be either a file or a PKCS #11 URL

load-crl option.
................

This is the ``loads the provided crl'' option. This option takes a string argument. This option can be used with a file

load-data option.
.................

This is the ``loads auxiliary data'' option. This option takes a string argument. This option can be used with a file

password option.
................

This is the ``password to use'' option. This option takes a string argument. You can use this option to specify the password in the command line instead of reading it from the tty. Note, that the command line arguments are available for view in others in the system. Specifying password as '' is the same as specifying no password.

null-password option.
.....................

This is the ``enforce a null password'' option. This option enforces a NULL password. This is different than the empty or no password in schemas like PKCS #8.

empty-password option.
......................

This is the ``enforce an empty password'' option. This option enforces an empty password. This is different than the NULL or no password in schemas like PKCS #8.

cprint option.
..............

This is the ``in certain operations it prints the information in c-friendly format'' option. In certain operations it prints the information in C-friendly format, suitable for including into C programs.

rsa option.
...........

This is the ``generate rsa key'' option. When combined with --generate-privkey generates an RSA private key.

NOTE: THIS OPTION IS DEPRECATED

dsa option.
...........

This is the ``generate dsa key'' option. When combined with --generate-privkey generates a DSA private key.

NOTE: THIS OPTION IS DEPRECATED

ecc option.
...........

This is the ``generate ecc (ecdsa) key'' option. When combined with --generate-privkey generates an elliptic curve private key to be used with ECDSA.

NOTE: THIS OPTION IS DEPRECATED

ecdsa option.
.............

This is an alias for the ecc option, see the ecc option documentation.

key-type option.
................

This is the ``specify the key type to use on key generation'' option. This option takes a string argument. This option can be combined with --generate-privkey, to specify the key type to be generated. Valid options are, 'rsa', 'rsa-pss', 'dsa', 'ecdsa', and 'ed25519'.

hash option.
............

This is the ``hash algorithm to use for signing'' option. This option takes a string argument. Available hash functions are SHA1, RMD160, SHA256, SHA384, SHA512, SHA3-224, SHA3-256, SHA3-384, SHA3-512.

salt-size option.
.................

This is the ``specify the rsa-pss key default salt size'' option. This option takes a number argument. Typical keys shouldn't set or restrict this option.

inder option.
.............

This is the ``use der format for input certificates, private keys, and dh parameters '' option.

This option has some usage constraints.  It:

  * can be disabled with --no-inder.

The input files will be assumed to be in DER or RAW format. Unlike options that in PEM input would allow multiple input data (e.g. multiple certificates), when reading in DER format a single data structure is read.

inraw option.
.............

This is an alias for the inder option, see the inder option documentation.

outder option.
..............

This is the ``use der format for output certificates, private keys, and dh parameters'' option.

This option has some usage constraints.  It:

  * can be disabled with --no-outder.

The output will be in DER or RAW format.

outraw option.
..............

This is an alias for the outder option, see the outder option documentation.

ask-pass option.
................

This is the ``enable interaction for entering password when in batch mode.'' option. This option will enable interaction to enter password when in batch mode. That is useful when the template option has been specified.

pkcs-cipher option.
...................

This is the ``cipher to use for pkcs #8 and #12 operations'' option. This option takes a string argument Cipher. Cipher may be one of 3des, 3des-pkcs12, aes-128, aes-192, aes-256, rc2-40, arcfour.

provider option.
................

This is the ``specify the pkcs #11 provider library'' option. This option takes a string argument. This will override the default options in /etc/gnutls/pkcs11.conf

certtool exit status
....................

One of the following exit values will be returned:

0 (EXIT_SUCCESS)
     Successful program execution.

1 (EXIT_FAILURE)
     The operation failed or the command syntax was not valid.

certtool See Also
.................

p11tool (1)

certtool Examples
.................

Generating private keys
.......................

To create an RSA private key, run:

     $ certtool --generate-privkey --outfile key.pem --rsa

To create a DSA or elliptic curves (ECDSA) private key use the above command combined with 'dsa' or 'ecc' options.

Generating certificate requests
...............................

To create a certificate request (needed when the certificate is  issued  by another party), run:

     certtool --generate-request --load-privkey key.pem \
        --outfile request.pem

If the private key is stored in a smart card you can generate a request by specifying the private key object URL.

     $ ./certtool --generate-request --load-privkey "pkcs11:..." \
       --load-pubkey "pkcs11:..." --outfile request.pem

Generating a self-signed certificate
....................................

To create a self signed certificate, use the command:

     $ certtool --generate-privkey --outfile ca-key.pem
     $ certtool --generate-self-signed --load-privkey ca-key.pem \
        --outfile ca-cert.pem

Note that a self-signed certificate usually belongs to a certificate authority, that signs other certificates.

Generating a certificate
........................

To generate a certificate using the previous request, use the command:

     $ certtool --generate-certificate --load-request request.pem \
        --outfile cert.pem --load-ca-certificate ca-cert.pem \
        --load-ca-privkey ca-key.pem

To generate a certificate using the private key only, use the command:

     $ certtool --generate-certificate --load-privkey key.pem \
        --outfile cert.pem --load-ca-certificate ca-cert.pem \
        --load-ca-privkey ca-key.pem

Certificate information
.......................

To view the certificate information, use:

     $ certtool --certificate-info --infile cert.pem

PKCS #12 structure generation
.............................

To generate a PKCS #12 structure using the previous key and certificate, use the command:

     $ certtool --load-certificate cert.pem --load-privkey key.pem \
        --to-p12 --outder --outfile key.p12

Some tools (reportedly web browsers) have problems with that file because it does not contain the CA certificate for the certificate. To work around that problem in the tool, you can use the --load-ca-certificate parameter as follows:

     $ certtool --load-ca-certificate ca.pem \
       --load-certificate cert.pem --load-privkey key.pem \
       --to-p12 --outder --outfile key.p12

Obtaining Diffie-Hellman parameters
...................................

To obtain the RFC7919 parameters for Diffie-Hellman key exchange, use the command:

     $ certtool --get-dh-params --outfile dh.pem --sec-param medium

Verifying a certificate
.......................

To verify a certificate in a file against the system's CA trust store use the following command:

     $ certtool --verify --infile cert.pem

It is also possible to simulate hostname verification with the following options:

     $ certtool --verify --verify-hostname www.example.com --infile cert.pem

Proxy certificate generation
............................

Proxy certificate can be used to delegate your credential to a temporary, typically short-lived, certificate.  To create one from the previously created certificate, first create a temporary key and then generate a proxy certificate for it, using the commands:

     $ certtool --generate-privkey > proxy-key.pem
     $ certtool --generate-proxy --load-ca-privkey key.pem \
       --load-privkey proxy-key.pem --load-certificate cert.pem \
       --outfile proxy-cert.pem

Certificate revocation list generation
......................................

To create an empty Certificate Revocation List (CRL) do:

     $ certtool --generate-crl --load-ca-privkey x509-ca-key.pem \
                --load-ca-certificate x509-ca.pem

To create a CRL that contains some revoked certificates, place the certificates in a file and use --load-certificate as follows:

     $ certtool --generate-crl --load-ca-privkey x509-ca-key.pem \
       --load-ca-certificate x509-ca.pem --load-certificate revoked-certs.pem

To verify a Certificate Revocation List (CRL) do:

     $ certtool --verify-crl --load-ca-certificate x509-ca.pem < crl.pem

certtool Files
..............

Certtool's template file format
...............................

A template file can be used to avoid the interactive questions of certtool. Initially create a file named 'cert.cfg' that contains the information about the certificate. The template can be used as below:

     $ 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

An example certtool template file that can be used to generate a certificate request or a self signed certificate follows.

     # 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 = GR

     # 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 = "none@none.org"

     # 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
     # Comment the field for a time-based 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:
     # http://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 = juliet@im.example.com

     # Names used in PKINIT
     #krb5_principal = user@REALM.COM
     #krb5_principal = HTTP/user@REALM.COM

     # A subject alternative name URI
     #uri = "http://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 = "none@none.org"

     # 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 = "http://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

     # Whether this certificate will be used to sign data (needed
     # in TLS DHE ciphersuites). This is the digitalSignature flag
     # in RFC5280 terminology.
     signing_key

     # Whether this certificate will be used to encrypt data (needed
     # in TLS RSA ciphersuites). Note that it is preferred to use different
     # keys for encryption and signing. This is the keyEncipherment flag
     # in RFC5280 terminology.
     encryption_key

     # Whether this key will be used to sign other certificates. The
     # keyCertSign flag in RFC5280 terminology.
     #cert_signing_key

     # Whether this key will be used to sign CRLs. The
     # cRLSign flag in RFC5280 terminology.
     #crl_signing_key

     # The keyAgreement flag of RFC5280. It's purpose is loosely
     # defined. Not use it unless required by a protocol.
     #key_agreement

     # The dataEncipherment flag of RFC5280. It's purpose is loosely
     # defined. Not use it unless required by a protocol.
     #data_encipherment

     # The nonRepudiation flag of RFC5280. It's purpose is loosely
     # defined. Not use it unless required by a protocol.
     #non_repudiation

     #### Extended key usage (key purposes)

     # The following extensions are used in an end certificate
     # 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-serverAuth (1.3.6.1.5.5.7.3.1) of
     # extended key usage.
     #tls_www_client

     # Whether this certificate will be used for a TLS server;
     # This sets the id-kp-clientAuth (1.3.6.1.5.5.7.3.2) 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 contraint. 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 = http://my.ocsp.server/ocsp

     # CA issuers URI
     # ca_issuers_uri = http://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 = http://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 = http://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 = "nmav@ex.net"

     # 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
     # Comment the field for a time-based number.
     #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"