certtool(1) | User Commands | certtool(1) |
certtool - GnuTLS certificate tool
certtool [-flags] [-flag [value]] [--option-name[[=| ]value]]
All arguments must be options.
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.
in the range 0 through 9999
Specifies the debug level.
The option combined with --load-request, --load-pubkey, --load-privkey and --load-certificate will extract the public key of the object in question.
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.
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.
This option is deprecated as a duplicate of --pubkey-info
NOTE: THIS OPTION IS DEPRECATED
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.
Will generate a PKCS #10 certificate request. To specify a private key use --load-privkey.
This option will dump the contents and print the metadata of the provided PKCS #12 structure.
The name to be used for the primary certificate and private key in a PKCS #12 file.
It requires a certificate, a private key and possibly a CA certificate to be specified.
This option will print information about encrypted PKCS #8 structures. That option does not require the decryption of the structure.
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.
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.
This option can be combined with --generate-privkey, to specify the key type to be generated. Valid options are, 'rsa', 'rsa-pss', 'dsa', 'ecdsa', 'ed25519, and 'ed448'.'. When combined with certificate generation it can be used to specify an RSA-PSS certificate when an RSA key is given.
Supported values are secp192r1, secp224r1, secp256r1, secp384r1 and secp521r1.
This is alternative to the bits option.
This needs to be combined with --load-privkey.
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.
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.
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).
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). To add new certificates to the CRL use --load-certificate.
The trusted certificate list must be loaded with --load-ca-certificate.
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.
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.
This is to be combined with one of the verify certificate options.
This is to be combined with one of the verify certificate options.
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.
This can be combined with --p7-verify, --verify or --verify-chain.
This option can be used to specify a certificate verification
profile. Certificate
verification profiles correspond to the security level. This should be
one of
'none', 'very weak', 'low', 'legacy', 'medium', 'high', 'ultra',
'future'. Note that by default no profile is applied, unless one is set
as minimum in the gnutls configuration file.
This option generates a PKCS #7 certificate container structure. To add certificates in the structure use --load-certificate and --load-crl.
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.
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.
This options works with --p7-sign or --p7-detached-sign and will include or exclude the signer's certificate into the generated signature.
This option will include a timestamp in the generated signature
This option can be combined with --p7-verify or --p7-info and will display the embedded signed data in the 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.
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
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.
This can be either a file or a PKCS #11 URL
This can be either a file or a PKCS #11 URL
This option can be used with a file
This option can be used with a file
This can be either a file or a PKCS #11 URL
This can be either a file or a PKCS #11 URL
This option can be used with a file
This option can be used with a file
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.
This option enforces a NULL password. This is different than the empty or no password in schemas like PKCS #8.
This option enforces an empty password. This is different than the NULL or no password in schemas like PKCS #8.
In certain operations it prints the information in C-friendly format, suitable for including into C programs.
When combined with --generate-privkey generates an RSA private key.
NOTE: THIS OPTION IS DEPRECATED
When combined with --generate-privkey generates a DSA private key.
NOTE: THIS OPTION IS DEPRECATED
When combined with --generate-privkey generates an elliptic curve private key to be used with ECDSA.
NOTE: THIS OPTION IS DEPRECATED
NOTE: THIS OPTION IS DEPRECATED
Available hash functions are SHA1, RMD160, SHA256, SHA384, SHA512, SHA3-224, SHA3-256, SHA3-384, SHA3-512.
Typical keys shouldn't set or restrict this 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.
The output will be in DER or RAW format.
NOTE: THIS OPTION IS DEPRECATED
This option will enable interaction to enter password when in batch mode. That is useful when the template option has been specified.
Cipher may be one of 3des, 3des-pkcs12, aes-128, aes-192, aes-256, rc2-40, arcfour.
This will override the default options in /etc/gnutls/pkcs11.conf
Output textual information before PEM-encoded data
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 # The value is in decimal (i.e. 1963) or hex (i.e. 0x07ab). # Comment the field for a random serial number. serial = 007 # In how many days, counting from today, this certificate will expire. # Use -1 if there is no expiration date. expiration_days = 700 # Alternatively you may set concrete dates and time. The GNU date string # formats are accepted. See: # https://www.gnu.org/software/tar/manual/html_node/Date-input-formats.html #activation_date = "2004-02-29 16:21:42" #expiration_date = "2025-02-29 16:24:41" # X.509 v3 extensions # A dnsname in case of a WWW server. #dns_name = "www.none.org" #dns_name = "www.morethanone.org" # An othername defined by an OID and a hex encoded string #other_name = "1.3.6.1.5.2.2 302ca00d1b0b56414e5245494e2e4f5247a11b3019a006020400000002a10f300d1b047269636b1b0561646d696e" #other_name_utf8 = "1.2.4.5.6 A UTF8 string" #other_name_octet = "1.2.4.5.6 A string that will be encoded as ASN.1 octet string" # Allows writing an XmppAddr Identifier #xmpp_name = 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 = "https://www.example.com" # An IP address in case of a server. #ip_address = "192.168.1.1" # An email in case of a person email = "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 = "https://www.getcrl.crl/getcrl/" # Whether this is a CA certificate or not #ca # Subject Unique ID (in hex) #subject_unique_id = 00153224 # Issuer Unique ID (in hex) #issuer_unique_id = 00153225 #### Key usage # The following key usage flags are used by CAs and end certificates # 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-clientAuth (1.3.6.1.5.5.7.3.2) of # extended key usage. #tls_www_client # Whether this certificate will be used for a TLS server; # this sets the id-kp-serverAuth (1.3.6.1.5.5.7.3.1) of # extended key usage. #tls_www_server # Whether this key will be used to sign code. This sets the # id-kp-codeSigning (1.3.6.1.5.5.7.3.3) of extended key usage # extension. #code_signing_key # Whether this key will be used to sign OCSP data. This sets the # id-kp-OCSPSigning (1.3.6.1.5.5.7.3.9) of extended key usage extension. #ocsp_signing_key # Whether this key will be used for time stamping. This sets the # id-kp-timeStamping (1.3.6.1.5.5.7.3.8) of extended key usage extension. #time_stamping_key # Whether this key will be used for email protection. This sets the # id-kp-emailProtection (1.3.6.1.5.5.7.3.4) of extended key usage extension. #email_protection_key # Whether this key will be used for IPsec IKE operations (1.3.6.1.5.5.7.3.17). #ipsec_ike_key ## adding custom key purpose OIDs # for microsoft smart card logon # key_purpose_oid = 1.3.6.1.4.1.311.20.2.2 # for email protection # key_purpose_oid = 1.3.6.1.5.5.7.3.4 # for any purpose (must not be used in intermediate CA certificates) # key_purpose_oid = 2.5.29.37.0 ### end of key purpose OIDs ### Adding arbitrary extensions # This requires to provide the extension OIDs, as well as the extension data in # hex format. The following two options are available since GnuTLS 3.5.3. #add_extension = "1.2.3.4 0x0AAB01ACFE" # As above but encode the data as an octet string #add_extension = "1.2.3.4 octet_string(0x0AAB01ACFE)" # For portability critical extensions shouldn't be set to certificates. #add_critical_extension = "5.6.7.8 0x1AAB01ACFE" # When generating a certificate from a certificate # request, then honor the extensions stored in the request # and store them in the real certificate. #honor_crq_extensions # Alternatively only specific extensions can be copied. #honor_crq_ext = 2.5.29.17 #honor_crq_ext = 2.5.29.15 # Path length constraint. Sets the maximum number of # certificates that can be used to certify this certificate. # (i.e. the certificate chain length) #path_len = -1 #path_len = 2 # OCSP URI # ocsp_uri = https://my.ocsp.server/ocsp # CA issuers URI # ca_issuers_uri = https://my.ca.issuer # Certificate policies #policy1 = 1.3.6.1.4.1.5484.1.10.99.1.0 #policy1_txt = "This is a long policy to summarize" #policy1_url = https://www.example.com/a-policy-to-read #policy2 = 1.3.6.1.4.1.5484.1.10.99.1.1 #policy2_txt = "This is a short policy" #policy2_url = https://www.example.com/another-policy-to-read # The number of additional certificates that may appear in a # path before the anyPolicy is no longer acceptable. #inhibit_anypolicy_skip_certs 1 # Name constraints # DNS #nc_permit_dns = example.com #nc_exclude_dns = test.example.com # EMAIL #nc_permit_email = "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 # The value is in decimal (i.e. 1963) or hex (i.e. 0x07ab). # Comment the field for a time-based number. # Time-based CRL numbers generated in GnuTLS 3.6.3 and later # are significantly larger than those generated in previous # versions. Since CRL numbers need to be monotonic, you need # to specify the CRL number here manually if you intend to # downgrade to an earlier version than 3.6.3 after publishing # the CRL as it is not possible to specify CRL numbers greater # than 263-2 using hex notation in those versions. #crl_number = 5 # Specify the update dates more precisely. #crl_this_update_date = "2004-02-29 16:21:42" #crl_next_update_date = "2025-02-29 16:24:41" # The date that the certificates will be made seen as # being revoked. #crl_revocation_date = "2025-02-29 16:24:41"
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
Changing the certificate format
To convert the certificate from PEM to DER format, use:
$ certtool --certificate-info --infile cert.pem --outder --outfile cert.der
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
One of the following exit values will be returned:
p11tool (1), psktool (1), srptool (1)
Nikos Mavrogiannopoulos, Simon Josefsson and others; see /usr/share/doc/gnutls/AUTHORS for a complete list.
Copyright (C) 2000-2020 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.
Please send bug reports to: bugs@gnutls.org
This manual page was AutoGen-erated from the certtool option definitions.
2023-11-30 | 3.7.1 |