Code Signing Certificate Fundamentals
Build a clear understanding of how code signing works, how certificates establish software publisher identity, and how trust is maintained throughout the certificate lifecycle.
Code signing connects software to a verifiable publisher identity. A code signing certificate supports this process by allowing software publishers to sign applications, installers, scripts, drivers, and other executable content. The topics below explain the fundamental concepts behind that trust—from the signing process and certificate authorities to certificate chains, timestamping, issuance, expiration, and revocation.
Start with the fundamentals, then follow the trust lifecycle
These guides are arranged around the key questions people encounter when learning about code signing. Start with what code signing is and how it works, then explore how certificates create trust and how that trust is managed over time.
Understand Code Signing
Learn what code signing does and how the signing process protects software identity and integrity.
Understand Trust
See how certificates, certificate authorities, and certificate chains work together to establish trust.
Understand Signing Evidence
Explore timestamping and trusted publisher concepts and how they relate to signed software.
Understand the Lifecycle
Follow certificates from issuance through expiration and revocation.
Understand what code signing is and how it works
Before looking at certificates and trust chains, it is important to understand the purpose of code signing itself. These guides explain what code signing means, what happens during signing, and what a signed piece of software communicates to users and platforms.
What Is Code Signing?
Code signing is the process of digitally signing software or other executable content to associate it with a verified publisher identity and protect the signed content from undetected changes. This guide provides the foundation for understanding why software publishers use code signing.
How Code Signing Works
Code signing involves cryptographic keys, a signing operation, and a digital signature that can be checked when software is distributed or installed. Learn how these components work together to create verifiable evidence about signed software. Learn how to verify a code signature before distributing an application.
How certificates establish software trust
A code signing certificate does not create trust in isolation. Certificate authorities, certificate chains, and publisher identity all contribute to how signed software can be evaluated. The guide to how certificates establish trust explains how these pieces fit together. These guides break down the trust structure behind code signing.
How Code Signing Certificates Establish Trust
A certificate binds a publisher identity to a public key and provides information that can be evaluated during signature verification. Explore how certificate-based identity contributes to the trust placed in signed software.
Code Signing Certificate Chain Explained
A certificate chain connects an end-entity code signing certificate with the certificate authorities that support its trust. Learn how the different certificates in the chain relate to one another and why the chain matters during verification.
What Is a Certificate Authority in Code Signing?
A certificate authority, or CA, is responsible for issuing certificates after completing the required validation process. Understand the CA's role in establishing publisher identity and supporting the trust model used by code signing.
Timestamping and trusted publisher concepts
A digital signature provides evidence about signed content and its publisher, while timestamping can provide evidence about when the signature was created. Trusted publisher terminology is also commonly encountered when software is signed and presented to users. For the technical rules, see code signing timestamping standards.
Code Signing and Timestamping Explained
Timestamping adds trusted time information to a digital signature. Learn why timestamping is used with code signing, how it relates to certificate validity, and why it matters when signed software needs to remain verifiable after a certificate reaches expiration. You can also follow the practical steps to timestamp signed software.
What Is a Trusted Publisher in Code Signing?
A trusted publisher is associated with software whose digital signature can be successfully verified and whose publisher identity is trusted by the relevant software environment. This guide explains the concept and how it relates to signed software.
What Is a Trusted Publisher?
The term trusted publisher can appear in software security interfaces when a signed application has an identifiable publisher whose signature and certificate information can be verified. Explore what this terminology means in practice.
From certificate issuance to expiration and revocation
Code signing certificates have a defined lifecycle. They are issued after validation, remain valid for a specific period, and can expire or be revoked under certain circumstances. Understanding these stages makes it easier to manage signed software and certificate changes correctly, including knowing when to renew a code signing certificate.
How Is a Code Signing Certificate Issued?
Certificate issuance begins with an application and the validation required to confirm the applicant's identity. Learn what happens during the issuance process and how a certificate moves from application through validation to issuance.
What Happens When a Code Signing Certificate Is Revoked?
Revocation changes the trust status of a certificate before its scheduled expiration. Understand why a code signing certificate may be revoked, what revocation means for trust, and why it can affect software signing operations.
What Happens When a Code Signing Certificate Expires?
Every code signing certificate has a validity period. Learn what certificate expiration means, how it differs from revocation, and why signed software can require additional consideration when the certificate used for signing is no longer valid.
What Is the Code Signing Certificate Lifecycle?
The certificate lifecycle covers the major stages a certificate passes through, from application and issuance to active use, renewal, expiration, or revocation. This overview brings those stages together into one complete lifecycle. If a certificate expires or its key is compromised, review how to replace it safely.
Build a complete understanding of code signing
Code signing brings together cryptography, publisher identity, certificate authorities, trust chains, timestamps, and certificate lifecycle management. Use these fundamentals to understand how each component fits into the broader code signing ecosystem.