A Certificate Signing Request (CSR) is a pivotal step in securing a TLS/SSL certificate from a Certificate Authority (CA). It's an encoded file, often generated on the server where the certificate will be used. This file includes vital details like the organization's name, domain, locality, and country. Crucially, it contains a public key for the certificate and is authenticated with a private key. The CSR begins the process of obtaining a digital certificate, a key measure in verifying and safeguarding the security and authenticity of your website or server.
Generating an SSL/TLS certificate via a certificate signing request
An SSL/TLS certificate plays a pivotal role in enhancing the security of your website traffic by encrypting data transmitted to and from your site using a distinct code. To obtain an SSL certificate, you need to initiate a Certificate Signing Request (CSR) process.
- Generate a pair of private and public keys, which can be accomplished through various tools like OpenSSL.
- Use the private key to create a certificate signing request, resulting in the generation of a CSR file that needs to be submitted to a Certificate Authority (CA).
Behind-the-scenes details for certificate signing requests (CSRs)
For those who use the Public Key Cryptography Standards 10 (PKCS10) Certification Request Standard, one of the most common standards for certificate signing requests, users must provide an unsigned copy of their digital certificate to the CA. They can initiate this process by generating a CSR using cPanel, Exchange, IIS, Java Keytool, or OpenSSL. These methods generally create CSRs in the Base-64 based PEM format, which means there is a X.509 certificate encoded in text using the Base-64 encoding scheme.
At the time of creation, most server software suites ask the user to provide several pieces of information for validation purposes. Those details include the requester's fully qualified domain name (FQDN), legal name of the company, contact email address, physical address, and name of the division that would be handling the certificate. Additionally, users will need to send over their public key as well as its type and length. As explained by GlobalSign, the CA needs these bits of data to create an SSL certificate, which uses asymmetric cryptography based on a corresponding private and public key pair.
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What information is included in a certificate signing request?
A certificate signing request comprises a comprehensive array of information, with the key elements being business details, allowing the CA to authenticate your identity and company. The CSR should encompass pertinent information about your business, the public key, as well as details regarding the key type and length. Your CA will use the data from the CSR to build your TLS certificate. Here is the type of information that you should expect to include in your CSR.
- Common Name: Your server's Fully Qualified Domain Name (FQDN), for example, .example.com.
- Note: Expect a mismatch error if the common name doesn't precisely align with what you enter in your web browser.
- Organization: Your organization's official legal name, including any suffixes like Inc., Corp., or LLC, if they apply.
- Note: Avoid shortening any part of your organization's legal name.
- Organization Unit: The specific department within your organization that is handling the certificate, such as the IT Department.
- Locality: The city where your organization operates.
- Note: Refrain from using abbreviations.
- State/Province/Region: The state, province, or region where your organization is situated.
- Note: Do not abbreviate this information.
- Country: The two-letter ISO code representing your organization's country.
- Email Address: A contact email for your organization.
- Public Key: The public key to be embedded in your certificate.
- Note: This key is generated automatically for encryption purposes, while its private counterpart is for decryption.
- Key Length and Type: The length of the key pair, indicating the encryption strength and its vulnerability to brute force attacks.
- Note: RSA 2048 bits is standard, though some Certificate Authorities (CAs) may support larger sizes like RSA 4096 bits.
- Signature Algorithm: The hash algorithm your CA uses to sign certificates, creating unique hashes from files.
What does a certificate signing request look like?
A CSR is commonly encoded in Base-64, which is a standard format used to depict binary data as ASCII text. The resulting Base-64 encoded CSR will appear as an extended sequence of seemingly random characters.
What Is Base-64?
Base-64 is a widely adopted encoding format designed for the representation of binary data in ASCII text. This format facilitates the transformation of binary data into a human-readable format that can be effortlessly transmitted over the internet. When generating a CSR, it is necessary to encode it using Base-64 to enable the CA to handle it.
What Is ASCII?
ASCII, which stands for American Standard Code for Information Interchange, serves as a standardized character encoding system employed in the digital realm. It assigns a distinct numeric value to each character in the alphabet.
Figure 1: Example of certificate signing request code
How do you create a Certificate Signing Request?
Generating a CSR involves several steps. Firstly, you'll need to generate a private key, which is essentially a confidential code used for encrypting information. It's crucial to safeguard this key as it plays an important role in decrypting traffic to your website.
Creating a private key
A private key generates its corresponding public key through mathematical processes, and these two keys constitute a "key pair." Private keys are utilized for decrypting data that has been encrypted with their matching public keys. Conversely, public keys are applied to confirm the authenticity of digital signatures generated with their respective private keys.
Many web servers and runtime platforms, including Internet Information Services (IIS), feature integrated functionalities for creating CSR (Certificate Signing Request). As another option, the OpenSSL command-line utility allows for the creation of a private key, resulting in a 2048-bit length key file labeled example.com.key.
Generating a CSR
Once you've generated a private key, you can use it to craft a CSR file. This file contains the information mentioned earlier and is usually encoded in Base-64. You can also create the CSR file using the OpenSSL command-line tool.
It's important to note that SSL/TLS certificates have a validity period, typically ranging from one to several years. When the certificate expires, it must be renewed or replaced with a new one. The CSR plays a role in the renewal process.
Submission to a Certificate Authority (CA)
After generating a CSR, you must submit it to a Certificate Authority (CA). The CA leverages the data in the CSR request to generate an SSL/TLS certificate for your website. Different types of certificates, such as domain-validated (DV), organization-validated (OV), and extended validation (EV) certificates, offer varying levels of validation and trust.
Certificates can also be revoked if they are compromised or for other reasons, and it's important to keep track of certificate revocation. Intermediate certificates play a role in the certificate chain.
Installing the Certificate CSR
After obtaining your SSL/TLS certificate from the Certificate Authority (CA), the next step involves setting it up on your server. The specific method of installation can differ based on the server and software you're using, but generally, there's a common approach to deploying SSL/TLS certificates across most server environments.
You'll start by copying the certificate files (the .crt and .key files) to your server. Subsequently, you'll configure the server to use the SSL/TLS certificate. The specific steps involved will depend on the server software you are using but generally involve adding the certificate files to a configuration file and restarting the server.
Additionally, it's crucial to securely store private keys, and best practices may include using hardware security modules (HSMs) or secure key management practices. Regularly monitoring certificate expirations and renewals is essential to maintain security, and backups of private keys and certificates should be performed to avoid data loss in case of server issues. The selection of a trusted Certificate Authority (CA) and choosing the right SSL/TLS certificate for your specific needs should also be carefully considered.
How to simplify a seemingly complex certificate signing request process
Clearly, organizations must complete multiple steps and track many different pieces of information to properly submit a CSR. To make this process easier, companies should consider generating key pairs and CSRs as well as managing and enforcing trust stores from a central location. Such an approach would simplify administration and ensure that all policies governing certificate content during the certificate request process are enforced automatically.
Venafi's solution makes CSR generation easier, as it enables organizations to create their requests from a central enrollment portal. The solution also has the ability to define default values, which decreases the time needed to complete a CSR. Lastly, companies can use the enrollment portal to integrate with any CA. This further simplifies the generation and storage of CSRs and key pairs.
Streamlining Certificate Signing Requests with Venafi
Venafi's TLS Protect offers a comprehensive solution for managing Certificate Signing Requests (CSRs), crucial for the deployment of TLS certificates across enterprise environments. By centralizing the CSR generation process, TLS Protect allows organizations to streamline the creation, submission, and tracking of these requests, significantly reducing the complexity and time involved. With its integrated platform, TLS Protect ensures that default values for CSR fields can be predefined, enhancing consistency and security standards across all certificates. Additionally, its seamless integration capabilities with various Certificate Authorities (CAs) simplify the management of the lifecycle of certificates, from issuance to renewal or revocation. This not only facilitates the generation and storage of CSRs and key pairs but also bolsters an organization's ability to enforce policy compliance, automate certificate processes, and secure its digital assets effectively.
Ready to take control of your certificate management? Discover how Venafi TLS Protect can transform your organization's security posture by scheduling a demo today.
(This post has been updated. It was originally published on August 21, 2018.)