certtool(1)

NAME
certtool - GnuTLS certificate tool

SYNOPSIS
certtool [-flag [value]]... [--opt-name[[=| ]value]]...

All arguments must be options.

DESCRIPTION
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.

OPTIONS

-d number, --debug=number
    Enable debugging. This option takes an integer number as its argument. The value of number is constrained to being:
    in the range  0 through 9999

    Specifies the debug level.

-V, --verbose
    More verbose output. This option may appear an unlimited number of times.

--infile=file
    Input file.

--outfile=string
    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. This option 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.

-e, --verify-chain
    Verify a PEM encoded certificate chain.

    The last certificate in the chain must be a self signed one.

--verify
    Verify a PEM encoded certificate chain using a trusted list.

    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
    Verify a CRL using a trusted list. This option must appear in combination with the following options: load-ca-certificate.

    The trusted certificate list must be loaded with --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.

    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.

--dh-info
    Print information PKCS #3 encoded Diffie-Hellman parameters.

--load-privkey=string
    Loads a private key file.

    This can be either a file or a PKCS #11 URL

--load-pubkey=string
    Loads a public key file.

    This can be either a file or a PKCS #11 URL

--load-request=file
    Loads a certificate request file.

--load-certificate=string
    Loads a certificate file.

    This can be either a file or a PKCS #11 URL

--load-ca-privkey=string
    Loads the certificate authority's private key file.

    This can be either a file or a PKCS #11 URL

--load-ca-certificate=string
    Loads the certificate authority's certificate file.

    This can be either a file or a PKCS #11 URL

--password=string
    Password to use.

    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.

--hex-numbers
    Print big number in an easier format to parse.

--cprint
    In certain operations it prints the information in C-friendly format.

    In certain operations it prints the information in C-friendly format, suitable for including into C programs.

--null-password
    Enforce a NULL password.

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

--empty-password
    Enforce an empty password.

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

-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.

    The option combined with --load-request, --load-pubkey, --load-privkey and --load-certificate will extract the public key of the object in question.

--v1
    Generate an X.509 version 1 certificate (with no extensions).

--to-p12
    Generate a PKCS #12 structure. This option 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.

--to-p8
    Generate a PKCS #8 structure.

-8, --pkcs8
    Use PKCS #8 format for private keys.

--rsa
    Generate RSA key.

    When combined with --generate-privkey generates an RSA private key.

--dsa
    Generate DSA key.

    When combined with --generate-privkey generates a DSA private key.

--ecc
    Generate ECC (ECDSA) key.

    When combined with --generate-privkey generates an elliptic curve private key to be used with ECDSA.

--ecdsa
    This is an alias for the --ecc option.

--hash=string
    Hash algorithm to use for signing.

    Available hash functions are SHA1, RMD160, SHA256, SHA384, SHA512.

--inder, --no-inder
    Use DER format for input certificates, private keys, and DH parameters . The no-inder form will disable the option.

    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
    This is an alias for the --inder option.

--outder, --no-outder
    Use DER format for output certificates, private keys, and DH parameters. The no-outder form will disable the option.

    The output will be in DER or RAW format.

--outraw
    This is an alias for the --outder option.

--bits=number
    Specify the number of bits for key generate. This option takes an integer number as its argument.

--sec-param=security parameter
    Specify the security level [low, legacy, medium, high, ultra].

    This is alternative to the bits option.

--disable-quick-random
    No effect.

--template=file
    Template file to use for non-interactive operation.

--ask-pass
    Enable interaction for entering password when in batch mode..

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

--pkcs-cipher=cipher
    Cipher to use for PKCS #8 and #12 operations.

    Cipher may be one of 3des, 3des-pkcs12, aes-128, aes-192, aes-256, rc2-40, arcfour.

--provider=file
    Specify the PKCS #11 provider library.

    This will override the default options in /etc/gnutls/pkcs11.conf

-h, --help
    Display usage information and exit.

-!, --more-help
    Pass the extended usage information through a pager.

-v [{v|c|n}], --version[={v|c|n}]
    Output version of program and exit. The default mode is `v', a simple version. The `c' mode will print copyright information and `n' will print the full copyright notice.

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

# 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

# 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

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

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.

70 (EX_SOFTWARE)
    libopts had an internal operational error. Please report it to autogen-users@lists.sourceforge.net. Thank you.

SEE ALSO
    p11tool (1)

AUTHORS
Nikos Mavrogiannopoulos, Simon Josefsson and others; see /usr/share/doc/gnutls/AUTHORS for a complete list.

COPYRIGHT
Copyright (C) 2000-2014 Free Software Foundation, and others all rights reserved. This program is released under the terms of the GNU General Public License, version 3 or later.

BUGS
Please send bug reports to: bugs@gnutls.org

NOTES
This manual page was AutoGen-erated from the certtool option definitions.