Jason Parms

Is your software code legitimate? To answer this question, a code signing certificate came into force. We all while downloading software or drivers, prefer authenticated software as pirated software can steal your data. However, many of you do not know detailed information about Code Signing and how it works. In this informative article, we will discuss Code Signing, its functionality, and best practices.

What is Code Signing Certificate?

Code Signing certificate establishes publisher’s identity through validation and signs a code for software, drivers, executables. After verifying the publisher’s identity, a Code signing certificate ensures that the software is safe to download. Code Signing certificate allows developers to distribute their software online and verifies them as an author of the software. The certificate also ensures that the code is not modified in any way since it is signed. Moreover, a timestamp does not let the code expires even the certificate is expired.

How Code Signing Works?

Code Signing certificates and an SSL certificate have many similarities like purchase, verification, and installation. However, we will go through the process of How does Code Signing certificate works.

Buy a certificate.

Code Signing certificates are available in two types: Organization validation and Extended Validation certificate type. An individual or an organization can buy the certificate type as per requirement.

Identity Verification.

Once you purchase a code signing certificate, the certificate authority (CA) begins verifying the identity of an individual or organization. The CA wants to confirm that you are running a business and distributing software in good faith.

Install Code Signing Certificate.

A code signing certificate can be installed on different servers. Once you get the certificate, you can install it on the desired platform.

Sign Executables or Scripts.

After installation, a developer signs the software with a digital signature. A signature is nothing but a data string that hashed to show your identity and ensures that the code remains intact. The signature is added with the developer’s private key.

sign executables or scripts - code signing certificate

Software Downloading.

Upon downloading the software, the user’s system software decrypts the digital signature with its public key. After that, the system checks for a root certificate with a verified identity to trust the signature.

software downloading

Match Keys.

If both hashed used at the time of signing software and downloading a software match, then the download continues else, it shows untrusted publisher warning.

Why Code Signing is important?

The rise of mobile application and malware distribution has made Code Signing certificate significant. Users will not download untrusted software as they may contain trojan and other malware that can silently collect users’ data in the background. A reliable software, the application can win user’s trust as well as increase the download ratio.

With a Code Signing certificate, a publisher can distribute software easily and generate more revenue. On the other side, users will get authenticated software that is digitally signed and whose publisher’s identity is verified. A pirated software can cause security warnings while downloading and a Code Signing certificate removes this hurdle and offers a secured environment to users.

Best Practices for Code Signing Certificate

To maximize the safety of a private key and the effectiveness of a code signing certificate, an organization should follow below Code Signing Best Practice.

Limited Access to Key

Organization should restrict access to a private key as well it should be stored on limited systems. There should be limited staff who can access a key and such key should have physical security like locked cabinets, key card protected doors.

Use of Cryptographic hardware product.

The best example is the hardware security module that is created to safeguard a private key. Hardware products should have passed FIPS-140 Level 2 certification. Hardware must be protected with a strong password. A password can be a combination of special characters, uppercase and lowercase letters, numbers.

Timestamping

Timestamp keeps the code valid in the event of certificate expiry. Software remains trusted with a timestamp. The object of a timestamp is to valid signature and extend its lifespan.

Test Signing and Release Signing

A test signing certificate can be a self-signed certificate or issued by an internal certificate authority. A release signing certificate signs the product code that will be used by end-users. The strength level of security may not be the same as the release signing certificate. The test signing certificate may chain to a different root than the release signing certificate. The infrastructure of test signing, and release signing should be different.

Code Authenticity

A code authenticity should be maintained before it is submitted for the signing process. A proper signing and approval process will prevent the signing of malicious code.

Scan for Virus

Code signing does not scan inside of a code, but it only authenticates the code. It is wise to scan the code before performing a code signing process. Every change in code should be manually examined as a malware scanner sometimes skips detection.

Change of Keys and revocation

If there is found any flaw in code, an organization should immediately revoke the code signing certificate. Frequent changes of keys and certificates can avert such issues. If any certificate is revoked then, it should be reported to the direct certificate authority. A compromised certificate indicates that the private key is stolen/accessed by any unauthorized person or a malicious application was signed.

Keep Updated

An organization should keep updated with the changing algorithm and industry practices. If any security flaw is found, the organization should immediately respond to it.

Organization Policies

For any internal and external changes, there should be a circulated policy document. The policy about the Code Signing certificate should specify access to signing the code, approved tools, types of certificates, storage of private keys.

Finally, a Code Signing certificate is inevitable security in today’s time where cybercrime is finding new ways to infiltrate the system and introduces malicious applications in the market. The above practices will make the Code Signing certificate more influential and reliable among users. It will take a single mistake and the company will fall victim to software tampering.