What is Code Signing Certificate?

How Does Code Signing Works

Consumers must remain very cautious while downloading software from the internet. They must be wary of third parties masquerading as software providers. Resources like code signing help identify the source and the kind of software coming your way.

Code signing is an operation in which a software developer or distributor puts digital signatures on files that are sent out. This assures the users that they are receiving software that does what the creator says it will. The signature acts as proof the code has not been tampered with or modified from its original form.

This article talks everything about the importance, advantages, weaknesses, of the code signing certificates.

Importance of Code Signing

With the ability to download so much software from the Internet, code signing has become more and more important for software developers and distributors to use. Cybercriminals can easily attack and disguise themselves as a legitimate source to plant malware on a victim’s computer. Code signing gives complete surety that these types of attacks cannot occur, as long as users only download software deemed safe by their operating system. Nowadays, when software is downloaded onto a computer, the Operating System checks for the digital certificate created through code signing, to assure the safety of the software attempting to be installed. If no digital certificate is found, then the user is alerted to this fact, and prompted to either stop or continue the installation.

How Does Code Signing Work?

How Does Code Signing Work

There are several steps in code signing. The first step is, to begin with, the creation of a unique key pair. The key pair created is a public-private key pair, as the code signing utilizes public key cryptography. Once the key pair is created, the public key is sent to a trusted certificate authority, or CA, which verifies that the key belongs to the owner by returning the public key to the software developer, along with a digitally signed code signing certificate. A CA is a highly trusted entity given the responsibility of signing and generating digital certificates. The certificate, with the attached public key, returned by the CA confirms the trustworthiness of the developer and any software they create.

The public key and a digital code signing certificate return and, the code of the software is run through a hash function. A hash function is a one-way function that turns the text put into the function into an arbitrary mixture of values that cannot be reversed. This provides a value to compare with when the data is sent to the consumer. The output, or digest, is then encrypted by the private key. The reason the private key is used for encryption, as opposed to the public key, is because the developer wants anyone to be able to read the message, but no one to be able to tamper with it. The digest, code signing certificate, and hash function are now combined into a signature block and placed into the software, which is sent to the consumer.

When the software is received, the consumer’s computer first checks the authenticity of the code signing certificate. Once the authenticity is confirmed, the digest is then decrypted with the public key of the originally created key pair. The hash function is then used on the software’s code, and the resulting digest is compared to the digest sent by the developer. If the digests match, then the software is safe to install.

Advantages of Code Signing

There are several benefits of Code Signing. Some of them are listed below as they are the most guaranteed benefits.

Builds Trust in The Software

With code signing, users can trust the software they are downloading, and need not worry about downloading malware onto their computer or mobile device. This authentication acts as a two-way street, with code signing promoting trust on both sides of the exchange. Not only can the user trust the sender, but the developer can also trust their software got to the correct location and is not being misused.

High in Demand by Top Brands

Since many of the biggest trusted mobile and web application stores, such as the IOS AppStore or Google’s Play Store, require comodo code signing certificate, developers can distribute their software through even more platforms.

Weaknesses of Code Signing

Some of the weaknesses in Code Signing make it difficult for the users to overcome. Let us see which are they?

Lesser Approach To Handle Private Key

Improper management of the private key created at the beginning of the code signing process can result in the insecurity of the software being sent. If a legitimate private key is stolen, then the attacker can encode their malicious software with the private key, which will tell the user that the software is safe to use, even if it isn’t.

Threat Towards Data Leakage

Threat actors can obtain a trusted certificate, but what deters most attackers is the need to provide identification information to obtain a certificate. If malicious software is distributed with a legitimate certificate, the developer can be identified and stopped.

User Errors While Installation

If the user allows the installation of the software, even if the Operating System says it is not code-signed, then code signing is rendered useless.

How To Prevent Weaknesses?

  1. For the protection of encryption keys, Hardware Security Modules, or HSMs, should be used. An HSM is a specialized, highly trusted physical device. It is a network computer that performs all the major cryptographic operations including encryption, decryption, authentication, key management, key exchange, etc. They are tamper-resistant and use extremely secure cryptographic operations.
  2. Along with HSMs, the principle of least privilege should be used with keys, to ensure only users who need the key have access to it
  3. Finally, caution should always be used with code signing. Only download and install software that is code signed by a trusted CA.


You must have now understood how code signing works as well as the answer to the questions, “what is code signing?” and “what is a code signing certificate?” With this information tucked securely under your belt, you can see why code signing certificates are not only useful for software developers, but also for anyone who sends secure information online.

The best way for companies to significantly mitigate the risks that cybercriminals obtain and use their code signing credential is to enforce secure code signing processes. Key components of that process should include requiring that keys are securely and centrally stored and ensuring that code signing processes are well defined and automatically enforced.