Code Signing Certificates: What They Do and How to Apply

Software is central to everyday life and business, but cyberattacks and malware make trust in downloaded applications a serious concern. How can a developer demonstrate who published a program and whether it has changed since signing? Code signing certificates are an important part of the answer. This article explains their purpose, benefits and application process.

1. What is a code signing certificate?

A code signing certificate enables a developer to digitally sign supported executable files, scripts and other software content. It binds a verified publisher identity to a public key, allowing recipients to check the signature and detect changes made after signing.

This supports safer software distribution and protects the publisher’s identity. It does not independently prove that the original software is free of viruses, spyware or other malicious behavior. A valid signature establishes origin and integrity, not a security audit of the code.

The source article lists executables, applications, plug-ins, Java, Microsoft Office macros/VBA, Mozilla objects and Microsoft Silverlight, with examples including .exe, .dll, .cab, .ocx, .msi and .xpi. Some of these are legacy ecosystems. Actual support depends on the certificate, signing tool and platform; a commercial certificate is not automatically accepted by every application store or format.

Types of code signing certificates

• OV code signing: Requires organizational and contact verification, commonly including a phone check. The original article gives a typical validation estimate of 1–3 business days and describes delivery on a USB hardware token (UKEY).
• EV code signing: Adds more extensive validation, an application agreement and final checks. The original estimate is 1–5 business days, also with USB-token delivery. Actual processing and shipping times depend on the CA, documents and chosen service.

Important clarification: The original text promises immediate SmartScreen reputation from EV signing. Microsoft states that this behavior no longer exists: both OV- and EV-signed new applications can still be marked as unrecognized. See Microsoft’s SmartScreen reputation guidance.

EV also has a role in Microsoft’s hardware developer enrollment and submission process. A hardware dashboard account needs an associated EV certificate for attestation or Windows Hardware Compatibility Program submissions. This does not mean that merely signing a Windows 11 kernel driver yourself guarantees installation; Microsoft’s applicable driver-signing process must be followed. See Microsoft’s driver code signing requirements.

2. What does code signing provide?

1. Verified publisher identity. The CA checks the applicant’s identity, and a valid signature can display the verified publisher’s information.
2. Detection of code changes. Public-key signatures make post-signing modification detectable. They do not physically prevent someone from changing or copying the file.
3. Recognized publisher information. A valid, trusted signature can replace an “unknown publisher” label with the publisher’s name. Other security warnings may still appear.
4. A basis for reputation assessment. SmartScreen evaluates downloaded applications and files. Signing contributes publisher information, but does not guarantee immediate reputation or the removal of every warning.
5. Greater user confidence. Clear publisher identity can reduce uncertainty during download and installation. Higher download numbers are a possible business benefit, not a guaranteed result.
6. Support for platform requirements. The source names Apple, Google Play, Tencent and 360 distribution channels as examples of ecosystems using software signatures. Each has its own signing, enrollment and review rules; a general-purpose commercial code signing certificate does not replace platform-specific credentials.

3. How do you apply?

1. Choose a certificate type. Match your platform requirements and budget to an appropriate product.
2. Submit the required information. This may include company registration, legal representative identity, authorized contact, office details and contact information. Check the application carefully before submission.
3. Complete CA validation. The CA may verify the organization by phone and public records, such as a D‑U‑N‑S record or company registry. The source estimates 1–5 business days, but timing is not guaranteed.
4. Receive and activate the signing method. For the USB-token product described in the source, the token is shipped after approval. Other supported services can use an HSM or managed signing; follow the requirements of the product you actually purchase.

4. Using and inspecting a signature

For a compatible Windows USB-token setup, install the required token software and use a signing tool such as SignTool to sign the application. Follow the CA and platform instructions, including appropriate timestamping where supported.

On Windows, right-click a supported signed application, open Properties, then Digital Signatures to inspect the signer, digest algorithm and timestamp information.

Code signing is a key part of trustworthy software distribution. Selecting and using it properly helps developers identify themselves, make tampering detectable and provide a clearer installation experience, while secure development and malware checks remain essential.

For questions or assistance, please contact us.