Acting as a certificate authority (CA) means dealing with cryptographic pairs ofprivate keys and public certificates. The very first cryptographic pair we'llcreate is the root pair. This consists of the root key (ca.key.pem) and rootcertificate (ca.cert.pem). This pair forms the identity of your CA.
Apr 12, 2020 With openssl self signed certificate you can generate private key with and without passphrase. If you use any type of encryption while creating private key then you will have to provide passphrase every time you try to access private key. Create a Root Certificate and self-sign it. Use the following commands to generate the csr and the certificate. Openssl req -new -sha256 -key contoso.key -out contoso.csr openssl x509 -req -sha256 -days 365 -in contoso.csr -signkey contoso.key -out contoso.crt The previous commands create the root certificate.
Typically, the root CA does not sign server or client certificates directly. Theroot CA is only ever used to create one or more intermediate CAs, which aretrusted by the root CA to sign certificates on their behalf. This is bestpractice. It allows the root key to be kept offline and unused as much aspossible, as any compromise of the root key is disastrous.
Note
It's best practice to create the root pair in a secure environment.Ideally, this should be on a fully encrypted, air gapped computer that ispermanently isolated from the Internet. Remove the wireless card and fillthe ethernet port with glue.
Prepare the directory¶
Choose a directory (/root/ca) to store all keys and certificates.
Create the directory structure. The index.txt and serial files act as aflat file database to keep track of signed certificates.
Prepare the configuration file¶
You must create a configuration file for OpenSSL to use. Copy the root CAconfiguration file from the Appendixto /root/ca/openssl.cnf.
The [ca] section is mandatory. Here we tell OpenSSL to use the optionsfrom the [CA_default] section.
The [CA_default] section contains a range of defaults. Make sure youdeclare the directory you chose earlier (/root/ca).
Openssl Generate Cert From Csr
We'll apply policy_strict for all root CA signatures, as the root CA isonly being used to create intermediate CAs.
We'll apply policy_loose for all intermediate CA signatures, as theintermediate CA is signing server and client certificates that may come from avariety of third-parties.
Options from the [req] section are applied when creating certificates orcertificate signing requests.
The [req_distinguished_name] section declares the information normallyrequired in a certificate signing request. You can optionally specify somedefaults.
The next few sections are extensions that can be applied when signingcertificates. For example, passing the -extensionsv3_ca command-lineargument will apply the options set in [v3_ca].
We'll apply the v3_ca extension when we create the root certificate.
We'll apply the v3_ca_intermediate extension when we create theintermediate certificate. pathlen:0ensures that there can be no further certificate authorities below theintermediate CA.
We'll apply the usr_cert extension when signing client certificates, suchas those used for remote user authentication.
We'll apply the server_cert extension when signing server certificates,such as those used for web servers.
Dll files fixer license key generator v 1.4. Type of this Setup: Offline Installer/Full Standalone Setup.
The crl_ext extension is automatically applied when creatingcertificate revocation lists.
We'll apply the ocsp extension when signing the Online CertificateStatus Protocol (OCSP) certificate.
Create the root key¶
Create the root key (ca.key.pem) and keep it absolutely secure. Anyone inpossession of the root key can issue trusted certificates. Encrypt the root keywith AES 256-bit encryption and a strong password.
Note
Use 4096 bits for all root and intermediate certificate authority keys.You'll still be able to sign server and client certificates of a shorterlength.
Create the root certificate¶
Use the root key (ca.key.pem) to create a root certificate (ca.cert.pem).Give the root certificate a long expiry date, such as twenty years. Once theroot certificate expires, all certificates signed by the CA become invalid.
Warning
Whenever you use the req tool, you must specify a configuration file touse with the -config option, otherwise OpenSSL will default to/etc/pki/tls/openssl.cnf.
Verify the root certificate¶
The output shows:
- the
SignatureAlgorithmused - the dates of certificate
Validity - the
Public-Keybit length - the
Issuer, which is the entity that signed the certificate - the
Subject, which refers to the certificate itself
The Issuer and Subject are identical as the certificate is self-signed.Note that all root certificates are self-signed.
The output also shows the X509v3 extensions. We applied the v3_caextension, so the options from [v3_ca] should be reflected in theoutput.
Version 1.0.4 — Last updated on 2015-12-09.
© Copyright 2013-2015, Jamie Nguyen. Created with Sphinx using a custom-built theme.
Finding your Private Key on Different Servers or Control Panels
Linux-Based (Apache, Nginx, LightHttpd)
Windows Operating Systems
Mac OS X
Tomcat
cPanel
WHM
Plesk
Synology NAS DSM
Webmin
VestaCP
DirectAdmin
Webuzo
What Is a Private Key?
What Is a Private Key?
You've received your SSL Certificate, and now you need to install it.
Firstly, let's go through some basics. Public Key Infrastructure (PKI) security is about using two unique keys: the Public Key is encrypted within your SSL Certificate, while the Private Key is generated on your server and kept secret.
All the information sent from a browser to a website server is encrypted with the Public Key, and gets decrypted on the server side with the Private Key. Together the key pair keeps communication secured, and one key will not work without the other.
How do I get it?
The Private Key is generated with your Certificate Signing Request (CSR). The CSR is submitted to the Certificate Authority right after you activate your Certificate. The Private Key must be kept safe and secret on your server or device, because later you'll need it for Certificate installation.
Note: all Certificates except Multi-Domains support Private Key generation in your browser. The key is always saved during SSL activation, we never receive this information. That's why it's important you save and back it up during the process if you use the in-browser automatic generation method. If the Private Key key file is lost, you'll need to reissue your Certificate.
Can I generate a new Private Key for my Certificate if I lose the old one?
Yes. You can generate a new private key and CSR, or use the automatic CSR and key generation during Certificate reissue (this option is available for all Certificates except for the Multi-Domains).
What does the Private Key look like?
It looks like a block of encoded data, starting and ending with headers, such as —–BEGIN RSA PRIVATE KEY—– and —–END RSA PRIVATE KEY—–.
You may not get to see this code when generating your CSR. Usually, it gets generated in the background with the CSR, and is automatically saved on your server. The system also fills the corresponding field automatically during installation of your Certificate in some control panels, such as cPanel.
The way this works varies depending on your web server, control panel, or any other tools used for CSR generation. Select the one that applies to you in the following section for specific guidance.
Finding your Private Key on Different Servers or Control Panels
Linux-based (Apache, NGINX, LightHttpd)
Normally, the CSR/RSA Private Key pairs on Linux-based operating systems are generated using the OpenSSL cryptographic engine, and saved as files with '.key' or '.pem' extensions on the server.
But no specific extensions are mandatory for text files in Linux, so the key file may have any name and extension, or no extension at all.
If you remember the whole name of the key file or at least part of it, you can use the following command in your console to find the file and its directory:
The slash symbol in this command implies that the search begins from the root directory of the server. This way you have more file options to view. The name of the file in between the single quotation marks should be the part of the name that you remember. To search for the file by extension, enter '*.key' to view all the files with the '.key' extension on your server.
Tip: often the name of the file corresponds to the domain name it was generated for e.g. 'domain_tld.key' or 'domain.tld.pem'.
Here's another useful command that lets you search files by their content:
This command will return the absolute path to the Private Key file if it's located on your server.
Windows Operating Systems (IIS, Exchange, Small Business server)
Windows servers don't let you view the Private Key in plain text format. When you import your Certificate via MMC or IIS, the Private Key is bound to it automatically if the CSR/Key pair has been generated on the same server.
If you need to obtain the Private Key to install your Certificate on a different server, you can export the key in a password protected PFX (PKCS#12) file. To do that, open the MMC Certificates snap-in tools following these steps:
Win+R >> mmc.exe >> OK >> File >> Add/Remove Snap-in >> Certificates >> Add >> Computer account >> Next >> Local computer >> Finish >> OK
Next, go to Certificate Enrollment Requests >> Certificates (if you haven't completed the Certificate request yet). If you've done that, you'd select Personal >> Certificates, then right-click the Certificate >> select All Tasks >> Export. The Export wizard will open, and give you instructions. You can find more detailed instructions here.
Once that's done, you will see the .pfx file containing your Certificate, CA-Bundle, and Private Key. To extract the key, use this tool. Choose the PKCS12 to PEM option, then upload the file and enter your chosen password.
Mac OS X
The Keychain tool in the Server application of Mac OS X won't allow you to access the Private Key via the graphic user interface. Instead use the Terminal, by opening /etc/certificates/ directory and clicking the file.
Its name should be something like '*.key.pem'. And the terminal commands to open the file are: cd /etc/certificates/ , then ls , and sudo nano test.key.pem.
Note: to check if the Private Key matches your Certificate, go here. Then paste the Certificate and the Private Key text codes into the required fields and click Match.
Tomcat
If your Tomcat SSL connector is configured in JSSE style, the Private Key must be in a password-protected keystore file with a .jks or .keystore extension. This file, unlike most other cases, is created before the CSR. To extract the Private Key, you'll need to convert the keystore into a PFX file with the following command:
Tips:
- 'Keystore.jks' should be replaced with your actual keystore name,
- 'keystore.p12' will be the name of the PKCS12 file you will receive,
- , and are the alias (key and keystore passwords that were entered during keystore generation),
- , and should be replaced with your JKS file alias, its password, and Private Key password.
- and should be replaced with the passwords you set for your new PKCS12 file and the Private Key.
After the PKCS12 file is generated, you can convert it to a PEM file with separated CRT, CA-Bundle and KEY files using this tool. Alternatively, use the following command in the terminal:
'Private.key' can be replaced with any key file title you like.
cPanel
- SSL/TLS Manager
a) The simplest way to get the appropriate key used during SSL installation is reflected in the below picture:
b) Alternatively, you can find the Private key in the Private keys section of the SSL/TLS Manager, which can be located in the cPanel main menu. You will see all the Private Keys ever generated in your cPanel. To view the code of the key, click View & Edit. If there are several keys in that menu, you can copy each of them to find a match with your Certificate code by using this tool. - File manager
On the homepage of your cPanel, click File manager. Find the folder named 'ssl' in the folder tree to the left (see screenshot). That folder will contain another folder named 'keys'. This key folder also contains all the keys ever generated in your cPanel.
WHM
Openssl Generate Cert And Key Generator
WHM stores your private keys and CSR codes in the SSL Storage Manager menu. On the homepage, click SSL/TLS >> SSL Storage Manager. To view the Private Key, click the magnifier icon next to the relevant key in the Key column.
Plesk
Click Domains >> your domain >> SSL/TLS Certificates. Practical large scale distributed key generation. You'll see a page like the one shown below. The key icon with the message 'Private key part supplied' means there is a matching key on your server.
To get it in plain text format, click the name and scroll down the page until you see the key code. Alternatively, click the green arrow icon on the right. This will download a PEM file, containing your Private Key, Certificate and CA-Bundle files (if they were previously imported to the server). The files can be opened in any text editor, such as Notepad.
Synology NAS DSM
When generating a CSR in Synology DSM, the Private Key is provided to you in a zip file on the last step. The key code is contained within a server.key file, that can be opened with a text editor, such as Notepad.
Webmin
Webmin works as a graphic user interface (GUI) on top of the command-line interface. There is also a file manager called Filemin, that you can use to browse the server file system and find your Private Key file. Alternatively, go to Others >> Command Shell and run the find or grep command, which you can find in the Linux Operating Systems section above.
VestaCP
Your Private Key needs to be saved during CSR generation, as it will not be available via the graphic user interface.
That said, you may be able to retrieve your Private Key via SSH. It is saved as a temporary file in the '/tmp' folder. The path to the file will look something like this: '/tmp/tmp.npAnkmWFcu/domain.com.key'.
Note: the files in the /tmp directory are deleted every time your server is rebooted, so this is not a safe place to store your Private Key.
To get the path to your key file, use this Linux command:
Where you see 'domain.com', replace this with the actual domain name you generated the CSR for.
The path to your key file can also be found using the grep command:
DirectAdmin
In the up-to-date version of DirectAdmin, your Private Key is saved on the server. Access it in the 'Paste a pre-generated Certificate and key' field during installation.
If that section is empty, it may mean the CSR and key were generated elsewhere, or the key was not saved in DirectAdmin due to a glitch. If a glitch happened, try retrieving the key via SSH. Usually it is saved in this directory:
/usr/local/directadmin/data/users//domains/.key
Note: and are your DirectAdmin details.
Webuzo
On the homepage, find the SSL management section by clicking the Private Keys button. This will display a list of all the Private Keys generated in Webuzo. To see the key code, click the pencil icon to the right under the Option column, as shown in the screenshot below:
Open Ssl Generate Cert And Key Download
To sum up, ways to find your private key fully depend on the interface of the web server where you generate the CSR. If the methods described above did not help you find the private key for your certificate, the only solution would be to generate a new CSR/private key pair and reissue your certificate and to make sure that the key is saved on your server/local computer this time.
