certtool man page

certtool — GnuTLS certificate tool

Synopsis

certtool [-flags] [-flag [value]] [--option-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.

The tool accepts files or URLs supported by GnuTLS. In case PIN is required for the URL access you can provide it using the environment variables GNUTLS_PIN and GNUTLS_SO_PIN.

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.

This option generates a CRL. 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).
-u, --update-certificate
Update a signed certificate.
-p, --generate-privkey
Generate a private key.
--provable
Generate a private key or parameters from a seed using a provable method.

This will use the FIPS-186-4 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 proven 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.
--verify-provable-privkey
Verify a private key generated from a seed using a provable method.

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=string
When generating a private key use the given hex-encoded seed.
-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. It can be combined with --verify-purpose or --verify-hostname.
--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. 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-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.
--verify-hostname=string
Specify a hostname to be used for certificate chain verification.

This is to be combined with one of the verify certificate options.
--verify-email=string
Specify a email to be used for certificate chain verification. This option 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=string
Specify a purpose OID to be used for certificate chain verification.

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
Allow broken algorithms, such as MD5 for verification.

This can be combined with --p7-verify, --verify or --verify-chain.
--generate-dh-params
Generate PKCS #3 encoded Diffie-Hellman parameters.

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.
--get-dh-params
Get the included PKCS #3 encoded Diffie-Hellman parameters.

Returns stored DH parameters in GnuTLS. Those parameters returned are defined in RFC7919, and can be considered standard parameters for a TLS key exchange.
--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=string
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
--load-crl=string
Loads the provided CRL.
--load-data=string
Loads auxiliary data.
--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.
--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.
--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.
-i, --certificate-info
Print information on the given certificate.
--fingerprint
Print the fingerprint of the given certificate.

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
Print the key ID of the given certificate.

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.
--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.

This option will dump the contents and print the metadata of the provided PKCS #12 structure.
--p12-name=string
The PKCS #12 friendly name to use.

The name to be used for the primary certificate and private key in a PKCS #12 file.
--p7-generate
Generate a PKCS #7 structure.

This option generates a PKCS #7 certificate container structure. To add certificates in the structure use --load-certificate and --load-crl.
--p7-sign
Signs using a PKCS #7 structure.

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.
--p7-detached-sign
Signs using a detached PKCS #7 structure.

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.
--p7-include-cert, --no-p7-include-cert
The signer's certificate will be included in the cert list.. The no-p7-include-cert form will disable the option. This option 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, --no-p7-time
Will include a timestamp in the PKCS #7 structure. The no-p7-time form will disable the option.

This option will include a timestamp in the generated signature
--p7-show-data, --no-p7-show-data
Will show the embedded data in the PKCS #7 structure. The no-p7-show-data form will disable the option.

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

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.
--p8-info
Print information on a PKCS #8 structure.

This option will print information about encrypted PKCS #8 structures. That option does not require the decryption of the 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.

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, SHA3-224, SHA3-256, SHA3-384, SHA3-512.
--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.
--curve=string
Specify the curve used for EC key generation.

Supported values are secp192r1, secp224r1, secp256r1, secp384r1 and secp521r1.
--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=string
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..

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=string
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 = 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

# 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"

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 medium

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.

Bugs

Please send bug reports to: bugs@gnutls.org

Notes

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

Referenced By

danetool(1), ocsptool(1), p11tool(1), psktool(1), tpmtool(1).

04 Nov 2016 3.5.6 User Commands