---
title: Types of digital certificates
description: "**Digital certificates** are essential for secure digital communication, particularly for encryption, authentication, and integrity. These certificates are based on **Public Key Infrastructure (PKI)** and are issued by **Certificate Authorities (CAs)**. Here's an overview of the main types of certificates and…"
url: "https://www.relianoid.com/resources/knowledge-base/misc/types-of-digital-certificates/"
updated: "2025-07-08"
category: Misc
---

# Types of digital certificates

**Digital certificates** are essential for secure digital communication, particularly for encryption, authentication, and integrity. These certificates are based on **Public Key Infrastructure (PKI)** and are issued by **Certificate Authorities (CAs)**. Here's an overview of the main types of certificates and their purposes:

## SSL/TLS Certificates

Used to secure communication between web servers and browsers (HTTPS). Types:

### Domain Validation (DV)

- Validates domain ownership only.
- Fast and inexpensive.

Example: personal websites or blogs.

### Organization Validation (OV)

- Validates domain ownership and organization identity.
- Better trust level, used for small to medium businesses.

### Extended Validation (EV)

- Most rigorous verification of identity and legal existence.
- Shows company name in the address bar (in some browsers).

Example: banking and e-commerce sites.

### Wildcard Certificates

- Secure a domain and all its subdomains (e.g., *.example.com).

### Multi-Domain (SAN/UCC) Certificates

- Secure multiple fully qualified domain names with one certificate.

## Code Signing Certificates

Used by developers to **digitally sign software**, ensuring the code hasn't been altered or tampered with after signing.

- **Standard Code Signing** – Verifies the publisher and ensures code integrity.
- **EV Code Signing** – Adds stricter verification, and helps avoid Windows SmartScreen warnings.

## Email Certificates (S/MIME)

Used to **digitally sign and encrypt email** messages.

- Ensures authenticity of sender.
- Prevents eavesdropping and spoofing.

Example: corporate email communications, legal or medical data.

## Client Certificates

Used to **authenticate clients (users or devices)** to servers.

- Works like a user password, but with stronger cryptography.
- Common in VPNs, secure APIs, mTLS, and enterprise networks.

## Root and Intermediate Certificates

Part of the certificate trust chain:

- **Root Certificate** – Top-level certificate trusted by systems (pre-installed in OS/browsers).
- **Intermediate Certificate** – Issued by root, used by CAs to issue end-entity certificates.

This **chain of trust** allows browsers to verify a website's certificate by following the path back to a trusted root.

## Self-Signed Certificates

Created and signed by the same entity.

- Used in internal systems or development environments.
- Not trusted by default (cause warnings in browsers).

## Comparison Table of Digital Certificate Types

| Certificate Type | Purpose | Identity Validation | Common Use Case | Trusted by Browsers |
| --- | --- | --- | --- | --- |
| DV SSL | Secure websites (basic HTTPS) | Domain only | Blogs, personal sites | Yes |
| OV SSL | Secure websites (verified org) | Domain + Org | Business websites | Yes |
| EV SSL | High-trust secure websites | Domain + Legal Org | Banks, e-commerce | Yes |
| Wildcard SSL | Secure all subdomains | Varies | Large websites with many subdomains | Yes |
| SAN / UCC | Secure multiple domains | Varies | Multi-site hosting, Exchange servers | Yes |
| Code Signing | Sign software/code | Org or Individual | Software publishers | Not browser-based |
| EV Code Signing | Sign code with SmartScreen support | Extended Org check | Enterprise software vendors | Not browser-based |
| S/MIME Email | Secure email (sign/encrypt) | Email + Identity | Corporate and legal email | With config |
| Client Auth | Authenticate users/devices | Client identity | VPN, APIs, internal apps | Not browser-based |
| Root Certificate | Trust anchor for CA hierarchy | N/A (pre-installed) | Trusted CAs (e.g., DigiCert, Let’s Encrypt) | Yes |
| Intermediate Cert | Link root and end-entity certs | Issued by root CA | CA-managed issuance | Yes |
| Self-Signed Cert | Local/development use | None (self-issued) | Dev, internal testing | No |

## Trust Chain Diagram

```
+----------------------------+
|     Trusted Root CA       |
| (Pre-installed in systems)|
+------------+--------------+
             |
             v
+----------------------------+
|  Intermediate CA (1..n)   |
| (Issued by Root CA)       |
+------------+--------------+
             |
             v
+----------------------------+
|  End-Entity Certificate    |
| (Website, client, email)   |
|  - DV, OV, EV, etc.        |
+----------------------------+

Browsers/clients validate the chain from leaf → intermediate → root.
```

For example, when visiting **https://relianoid.com**:

- The browser receives the end-entity cert.
- It checks that it’s signed by a known intermediate.
- Then it ensures that intermediate is trusted via a root CA.

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