What Is a Code Signing Certificate and Why It’s Essential

When users download software, they expect it to be secure and trustworthy. But how can they know the software hasn’t been tampered with? That’s where code signing certificates come in.

A code signing certificate proves the authenticity of software, ensuring it comes from a verified source and hasn’t been altered since it was signed. In this article, we’ll explore what a code signing certificate is, why it’s essential for developers, and how it safeguards users from malicious software.

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Table of Contents

1. What is a Code Signing Certificate?
2. Why is a Code Signing Certificate Important?
3. How Does a Code Signing Certificate Work?
4. How to Obtain a Code Signing Certificate
5. Best Practices for Code Signing
6. Common Challenges and How to Avoid Them
7. Why SSL Dragon is Your Best Choice for Code Signing Certificates

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What Is a Code Signing Certificate?

A code signing certificate is a digital certificate that verifies the authenticity of software or an application. It allows software developers to digitally sign their programs, scripts, or files, assuring users that the software is legitimate and hasn’t been tampered with since it was signed.

When a user downloads software, their operating system or browser often checks if the software is signed with a code signing certificate. This builds trust between the developer and the end user. Without this certificate, users will likely see security warnings or error messages suggesting the software could be malicious. This is why having a code signing certificate is essential for developers and organizations aiming to distribute secure software.

By signing your code, you’re ensuring the integrity of your application, helping users feel confident when installing and running your software. This practice is widely used across platforms, including Windows, macOS, and mobile apps.

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Why is a Code Signing Certificate Important?

A code signing certificate is crucial because it protects both developers and users. It ensures that the software has not been altered or corrupted after it was signed. Once signed, any modification to the code will break the digital signature, which alerts users that the code has been tampered with.

Here are a few key reasons why code signing certificates are essential:

• Avoids Security Warnings. Operating systems and browsers are designed to warn users when they are about to install unsigned software. These warnings can damage a developer’s reputation and lead to fewer downloads. With a valid code signing certificate, developers can prevent these warnings and provide a seamless user experience.
• Protects Against Malicious Attacks. Code signing acts as a line of defense against cyberattacks, where attackers might modify the signed code and inject malware. Without a certificate, users wouldn’t know if the software has been compromised. A signed application shows that it came directly from the developer and hasn’t been changed since it was signed.
• Builds Trust With Users. Most users are not tech-savvy enough to assess the safety of downloaded files. A code signing certificate provides a level of trust because it associates the software with a verified source, like a reputable developer or organization. When users see a trusted certificate, they are more likely to install and run the software.

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How Does a Code Signing Certificate Work?

The process of code signing involves using encryption to verify both the integrity of the code and the identity of the developer. Here’s how it works:

1. Key Generation. The developer generates two cryptographic keys: a public key and a private key. The private key is used to sign the code, and the public key will be available to anyone downloading the software to verify the signature.
2. Signing the Code. The code or software is signed with the private key. This digital signature is unique and ties the software to the developer’s identity. It also creates a “hash” of the code—a unique fingerprint that can be checked later.
3. Verification by Users. When users download and attempt to run the signed software, their system uses the public key to verify the signature. If the software has been altered in any way since it was signed, the system will detect that the hash has changed and alert the user.
4. Certificate Authority (CA) Role. A trusted Certificate Authority (CA) issues code signing certificates after verifying the identity of the developer or organization. Some well-known CAs include DigiCert, GlobalSign, and Sectigo. By signing the code, the developer assures users that a trusted CA has verified their identity.

The public key infrastructure (PKI) behind this process ensures that the software is secure and hasn’t been tampered with, allowing users to trust the download.

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How to Obtain a Code Signing Certificate

Acquiring a code signing certificate is a straightforward process, but it involves some key steps to ensure that your identity as a developer or organization is verified. Here’s a step-by-step guide to obtaining your certificate:

1. Choose a Certificate Authority (CA). These authorities issue code signing certificates after verifying your identity. You can buy the certificate directly from the Certificate Authority or through an SSL vendor like SSL Dragon. The second option is far better because the prices are much lower. 
2. Complete Identity Verification. Depending on the type of certificate you’re applying for, the CA will require you to submit documents to verify your identity.
3. Generate a Certificate Signing Request (CSR). This block of encoded text contains your public key and other information required to issue the certificate.
4. Submit the CSR and Install the Certificate. After the CA verifies your information, it will ship the code signing key on a Hardware Security Module (HSM) or alternatively provide a secure download link.
5. Apply the digital signature to your software. The process varies from system to system.

Note: Starting from June 1st, 2023, a new security measure is in place for code signing certificates. All code signing certificates must now be stored on hardware meeting specific security standards such as FIPS 140 Level 2, Common Criteria EAL 4+, or their equivalents.

As a result, the process of obtaining and installing certificates has changed. Certificate Authorities no longer support browser-based key generation, creating CSRs, and installing certificates on laptops or servers. Instead, if you opt for token+ shipment as your code signing delivery method, the CA will handle CSR generation. Alternatively, if you prefer to use your Hardware Security Module (HSM), follow your HSM provider’s instructions for CSR generation.

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Best Practices for Code Signing

While obtaining a code signing certificate is an essential first step, there are several best practices you should follow to ensure maximum security and compliance:

• Keep Your Private Keys Secure. Your private key is used to sign your code, and if it falls into the wrong hands, malicious actors can sign harmful software under your name. Always store your private keys in a secure environment, such as a hardware security module (HSM), and avoid sharing them.
• Use Timestamping. Adding a timestamp when signing your code is critical because it extends the validity of your signature beyond the expiration of your certificate. Even after your code signing certificate expires, the signature will still be considered valid as long as it was timestamped during the signing process.
• Renew Certificates Regularly. Code signing certificates typically expire after one to three years, depending on the CA. Make sure you keep track of expiration dates and renew your certificate before it expires. Allowing it to expire can lead to warnings or even security breaches if users continue to download unsigned versions of your software.
• Limit Access to Signing Tools. Ensure that only authorized personnel within your organization can access the tools used for code signing. This reduces the risk of internal misuse or accidental exposure of private keys.

By adhering to these best practices, you’ll ensure that your software remains secure, users are protected, and you maintain a professional reputation.

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Common Challenges and How to Avoid Them

Although code signing certificates provide significant benefits, developers may face some challenges during the process. Here are a few common issues and how to prevent them:

• Misuse of Private Keys. If private keys are lost or stolen, attackers can sign malicious software, compromising your reputation. To avoid this, always store your keys securely and limit access to them. You can also revoke a compromised certificate to prevent further damage.
• Operating System Trust Errors. Sometimes, users might receive trust errors if their operating system doesn’t recognize the CA that issued your certificate. Choose a widely trusted CA like DigiCert or GlobalSign to minimize this risk. Additionally, keep your certificates updated to ensure compatibility with the latest operating system requirements.

By being aware of these challenges and taking proactive steps to avoid them, you can ensure a smooth code signing process and protect your software from unnecessary risks.

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Why SSL Dragon is Your Best Choice for Code Signing Certificates

At SSL Dragon, we offer top-tier code signing certificates from industry-leading Certificate Authorities like DigiCert and Sectigo. With our easy-to-follow purchasing process, competitive pricing, and exceptional customer support, getting your certificate has never been more straightforward. Plus, all of our certificates include timestamping, ensuring your software remains trusted long after the certificate expires.

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