The CA issues the certificate for this specific request. The details should generally match the root CA. This removes authentication certificates that were required in the v1 SKU. Generate the self-signed root CA certificate: openssl req -x509 -sha256 -new -nodes -key rootCAKey.pem -days 3650 -out rootCACert.pem In this example, the validity period is 3650 days. Now to complete setup of openssl create certificate chain, we will also need intermediate certificate for the CA bundle. Thank you for highlighting this, I have updated the article. You can add upto "n" number of intermediate certificates in the certificate chain depending upon your requirement. We will also need a serial and index.txt file as we created for our Root CA Certificate. Could not open file or uri /root/tls/private/andre-root-ca-key.pem for loading CA private key [ ca] # `man ca` default_ca = CA_default The [CA_default] section in the openssl_root.cnf file contains the variables OpenSSL will use for the root CA.If you're using alternate directory names from this demo, update the file accordingly. The root CA is only ever used to create one or more intermediate CAs, which are trusted by the root CA to sign certificates on their behalf. You don't need to explicitly upload the root certificate in that case. This was very educational. Use the following command to generate the CSR: When prompted, type the password for the root key, and the organizational information for the custom CA: Country/Region, State, Org, OU, and the fully qualified domain name. SHA-256 is the default in later versions of OpenSSL, but earlier versions might use SHA-1. After openssl create certificate chain, to verify certificate chain use below command: The -sha256 option sets the hash algorithm to SHA-256. If the certificate is going to be used on a server, use the server_cert extension. Use the root private key to sign the root certificate. Signing the Root Certificate. We'll set up our own root CA. This guide demonstrates how to act as your own certificate authority (CA) using the OpenSSL command-line tools. Hi - can I chain more certificates on to a certificate I purchased from a CA? To convert the format of the Certificate to PEM format. CA Key and Certificate Creation. The openssl ca command and utility is a lightweight piece of software that can be used to perform minimal CA (Certification Authority) functions. If not, you can edit the hosts file to resolve the name. We will create root CA key using 4096 bits and 3DES encryption. A policy definition is a set of keys with the same name as the fields in a certificate’s distinguished name. Create a parent directory to store the certificates. The [ CA_default ] section contains a range of defaults. When I cat on the end-entity certificate, I see only a single BEGIN and END tag. Sign in to your computer where OpenSSL is installed and run the following command. ). Also, they may use outdated hash and cipher suites that may not be strong. Creating a root CA certificate and an end-entity certificate. If the intermediate key is compromised, the root CA can revoke the intermediate certificate and create a new intermediate cryptographic pair. You’ll be asked various questions (Country, State/Province, etc. The Application Gateway v2 SKU introduces the use of Trusted Root Certificates to allow backend servers. openssl> genrsa -aes256 -out private/ca.key.pem 4096. We applied the v3_ca extension, so the options from [ v3_ca ] should be reflected in the output. Now lunch the openssl.exe by running the below command > “C:\Program Files\OpenSSL-Win64\bin\openssl.exe” Use the “” to run the command. Linux, Cloud, Containers, Networking, Storage, Virtualization and many more topics, The majority of the files that the CA uses are visible to anyone on the system or at least to anyone who makes any use of the certificates issued by our CA. (change DOMAINNAME to match what you used in the openssl_root.cnf): We will also create sub directories under /root/tls/intermediate to store our keys and certificate files. For creating new CA chain bundle you can follow the same steps as I have mentioned here. This creates a password protected key. OpenSSL create certificate chain with root and intermediate certificate First, we need to create a “self-signed” root certificate. If you don't have an existing application gateway, see Quickstart: Direct web traffic with Azure Application Gateway - Azure portal. 05-04-2012 Luke Virtualization Certificate Authority, Certificate signing, openssl, Root CA, srm, vcenter 4 Comments Leave a Reply Cancel reply Your email address will not be published. I have an implementation question however as we have run into variations on where the intermediary certificates should be vs the root CA certificates. Your Root CA certificate remains unaffected and all you need to do is to renew only one subset of certificates. You can find OpenSSL bundled with many Linux distributions, such as Ubuntu. Set the appropriate number of days for your company. It allows the root key to be kept offline and unused as much as possible, as any compromise of the root key is disastrous. The following sample adds a trusted root certificate to the application gateway, creates a new HTTP setting and adds a new rule, assuming the backend pool and the listener exist already. When we create private key for Root CA certificate, … Make sure you declare the directory you chose earlier /root/tls. it isn't really possible of course. set OPENSSL_CONF=C:\Program Files\OpenSSL-Win64\bin\openssl.cfg. This is best practice. openssl req -config /etc/openssl.cnf -new -x509 -keyout private/cakey.pem \ -out cacert.pem -days 3650 This last command is better than “ -newcert” as it will place the files in the required locations and create a root CA valid for 10 years. Next we will use this Root and Intermediate CA bundle to sign and generate server and client certificates to configure end to end encryption for Apache web server in Linux. We will create new directory structure /root/tls/intermediate under our parent folder /root/tls to keep both the certificate files separate. For instructions on how to import certificate and upload them as server certificate on IIS, see HOW TO: Install Imported Certificates on a Web Server in Windows Server 2003. So I will not repeat the steps here again. A serial file is used to keep track of the last serial number that was used to issue a certificate. In the below example I have combined my Root and Intermediate CA certificates to openssl create certificate chain in Linux. The purpose of using an intermediate CA is primarily for security. i asked before i really understood the concepts involved. It's assumed that DNS has been configured to point the web server name (in this example, to your web server's IP address. Use the following commands to generate the csr and the certificate. Since .crt already contains the public key in the base-64 encoded format, just rename the file extension from .crt to .cer. The private key should be stored in hardware, or at least on a machine that is never put on a network. Do not delete or edit this file by hand. We will use v3_ca extension to create root CA certificate and v3_intermediate extension for intermediate CA certificate. The private key should never be disclosed to anyone not authorized to issue a certificate or CRL from our CA. Next openssl verify intermediate certificate against the root certificate. Create an Intermediate Key. In some countries, using the OpenSSL package can be against the law. This is useful in a number of situations, such as issuing server certificates to secure an intranet website, or for issuing certificates to clients to allow them to authenticate to a server. It identifies the root certificate authority (CA) that issued the server certificate and the server certificate is then used for the TLS/SSL communication. Add a crlnumber file to the intermediate CA directory tree. Once the key is created, you’ll generate the certificate signing request. A certificate chain or certificate CA bundle is a sequence of certificates, where each certificate in the chain is signed by the subsequent certificate. Thanks for providing this. Operating a CA with openssl ca The values under [ req ] section are applied when creating Certificate Signing Requests (CSR) or Certificates. In this step you'll take the place of VeriSign, Thawte, etc. Give the root certificate a long expiry date. openssl req -new -key device.key -out device.csr. Please note that the choice of “1” as a serial number is considered a security flaw for real certificates. 3. In case the CSR is only available with SHA-1, the CA can be used to sign CSR requests and enforce a different algorithm. $ openssl x509 -req -extfile < (printf "subjectAltName=DNS:YOUR_DOMAIN_NAME") -days 120 -in SERVER.csr -CA rootCA.crt -CAkey root_rsa.key -CAcreateserial -out SERVER.crt -sha256. 3. OpenSSL is somewhat quirky about how it handles this file. Browse to your website, and click the lock icon on your browser's address box to verify the site and certificate information. It identifies the root certificate authority (CA) that issued the server certificate and the server certificate is then used for the TLS/SSL communication. /root/tls and will modify the content of this file to create Root CA Certificate. The Root CA is the top level of certificate chain while intermediate CAs or Sub CAs are Certificate Authorities that issue off an intermediate root. When prompted, type the password for the root key, and the organizational information for the custom CA such as Country/Region, State, Org, OU, and the fully qualified domain name (this is the domain of the issuer). After you have created the OpenSSL configuration file, the next step is to create a self-signed root certificate that will be used to sign your localhost test certificate. Create a Root Certificate (this is self-signed certificate) openssl> req -config openssl.cnf \ -key private/ca.key.pem \ -new -x509 -days 7300 -sha256 -extensions v3_ca \ -out certs/ca.cert.pem. It expects the value to be in hex, and it must contain at least two digits, so we must pad the value by prepending a zero to it. We will use this file later to verify certificates signed by the intermediate CA. It’s important that no two certificates ever be issued with the same serial number from the same CA.