info gnutls

4.2.5 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.

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
   -s, --generate-self-signed  Generate a self-signed certificate
   -c, --generate-certificate  Generate a signed certificate
       --generate-proxy       Generates a proxy certificate
       --generate-crl         Generate a CRL
   -u, --update-certificate   Update a signed certificate
   -p, --generate-privkey     Generate a private key
   -q, --generate-request     Generate a PKCS #10 certificate request
                                - prohibits the option 'infile'
   -e, --verify-chain         Verify a PEM encoded certificate chain
       --verify               Verify a PEM encoded certificate chain using a trusted list
       --verify-crl           Verify a CRL using a trusted list
                                - requires the option 'load-ca-certificate'
       --generate-dh-params   Generate PKCS #3 encoded Diffie-Hellman parameters
       --get-dh-params        Get 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=file    Loads a certificate request file
                                - file must pre-exist
       --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
       --password=str         Password to use
       --hex-numbers          Print big number in an easier format to parse
       --cprint               In certain operations it prints the information in C-friendly format
       --null-password        Enforce a NULL password
   -i, --certificate-info     Print information on the given certificate
       --certificate-pubkey   Print certificate's public key
       --pgp-certificate-info  Print information on the given OpenPGP certificate
       --pgp-ring-info        Print information on the given OpenPGP keyring structure
   -l, --crl-info             Print information on the given CRL structure
       --crq-info             Print information on the given certificate request
       --no-crq-extensions    Do not use extensions in certificate requests
       --p12-info             Print information on a PKCS #12 structure
       --p7-info              Print information on a PKCS #7 structure
       --smime-to-p7          Convert S/MIME to PKCS #7 structure
   -k, --key-info             Print information on a private key
       --pgp-key-info         Print information on an OpenPGP private key
       --pubkey-info          Print information on a public key
       --v1                   Generate an X.509 version 1 certificate (with no extensions)
       --to-p12               Generate a PKCS #12 structure
                                - requires the option 'load-certificate'
       --to-p8                Generate a PKCS #8 structure
   -8, --pkcs8                Use PKCS #8 format for private keys
   -!, --rsa                  Generate RSA key
   -", --dsa                  Generate DSA key
   -#, --ecc                  Generate ECC (ECDSA) key
   -$, --ecdsa                an alias for the 'ecc' option
   -%, --hash=str             Hash algorithm to use for signing
   -&, --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
   -*, --bits=num             Specify the number of bits for key generate
   -+, --sec-param=str        Specify the security level [low, legacy, normal, high, ultra]
   -,, --disable-quick-random  No effect
   --, --template=file        Template file to use for non-interactive operation
                                - file must pre-exist
   -., --pkcs-cipher=str      Cipher to use for PKCS #8 and #12 operations
   -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.

Please send bug reports to:  <@PACKAGE_BUGREPORT@>

debug option (-d)

This is the “enable debugging” option. This option takes a number argument. Specifies the debug level.

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.

verify-chain option (-e)

This is the “verify a pem encoded certificate chain” option. The last certificate in the chain must be a self signed one.

verify option

This is the “verify a pem encoded certificate chain using a trusted list” option. The trusted certificate list can be loaded with –load-ca-certificate. If no certificate list is provided, then the system’s certificate list is used.

verify-crl option

This is the “verify a crl 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.

get-dh-params option

This is the “get the included pkcs #3 encoded diffie-hellman parameters” option. Returns stored DH parameters in GnuTLS. Those parameters are used in the SRP protocol. The parameters returned by fresh generation are more efficient since GnuTLS 3.0.9.

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-certificate option

This is the “loads a certificate file” option. This option takes a string argument. This can be either a file or a PKCS #11 URL

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

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.

null-password option

This is the “enforce a null password” option. This option enforces a NULL password. This may be different than the empty password in some schemas.

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.

to-p12 option

This is the “generate a pkcs #12 structure” option.

This option has some usage constraints. It:

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

It requires a certificate, a private key and possibly a CA certificate to be specified.

rsa option

This is the “generate rsa key” option. When combined with –generate-privkey generates an RSA private key.

dsa option

This is the “generate dsa key” option. When combined with –generate-privkey generates a DSA private key.

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.

ecdsa option

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

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.

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.

sec-param option

This is the “specify the security level [low, legacy, normal, high, ultra]” option. This option takes a string argument ‘Security parameter’. This is alternative to the bits option.

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.

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

Diffie-Hellman parameter generation

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

$ certtool --generate-dh-params --outfile dh.pem --sec-param normal

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=Nik,st=Attiki,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"

# 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"

# 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

# for microsoft smart card logon
# key_purpose_oid = 1.3.6.1.4.1.311.20.2.2

### Other predefined key purpose OIDs

# Whether this certificate will be used for a TLS client
#tls_www_client

# Whether this certificate will be used for a TLS server
#tls_www_server

# Whether this certificate will be used to sign data (needed
# in TLS DHE ciphersuites).
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.
encryption_key

# Whether this key will be used to sign other certificates.
#cert_signing_key

# Whether this key will be used to sign CRLs.
#crl_signing_key

# Whether this key will be used to sign code.
#code_signing_key

# Whether this key will be used to sign OCSP data.
#ocsp_signing_key

# Whether this key will be used for time stamping.
#time_stamping_key

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

### end of key purpose OIDs

# 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

# 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


# Options for proxy certificates
# proxy_policy_language = 1.3.6.1.5.5.7.21.1


# Options for generating a CRL

# next CRL update will be in 43 days (wow)
#crl_next_update = 43

# this is the 5th CRL by this CA
#crl_number = 5

This document was generated on February 9, 2014 using texi2html 5.0.

4.2.5 Invoking certtool

certtool help/usage (‘--help’)

debug option (-d)

generate-request option (-q)

verify-chain option (-e)

verify option

verify-crl option

get-dh-params option

load-privkey option

load-pubkey option

load-certificate option

load-ca-privkey option

load-ca-certificate option

cprint option

null-password option

pubkey-info option

to-p12 option

rsa option

dsa option

ecc option

ecdsa option

hash option

inder option

inraw option

outder option

outraw option

sec-param option

pkcs-cipher option

certtool exit status

certtool See Also

certtool Examples

Generating private keys

Generating certificate requests

Generating a self-signed certificate

Generating a certificate

Certificate information

PKCS #12 structure generation

Diffie-Hellman parameter generation

Proxy certificate generation

Certificate revocation list generation

certtool Files

Certtool’s template file format

certtool help/usage (‘`--help`’)