Further, in the SCEP, this entire process is automated. In modern enterprises with thousands of endpoints ranging from servers, mobile devices, network devices, and IoT systems, manually deploying certificates to each device is impractical and often error-prone. By utilizing SCEP, devices can request, enroll, and even renew their certificates without needing a human to click a button or check a box.
How does the simple certificate enrollment protocol work?
SCEP uses HTTP (to transport data) and PKI (to encrypt) to establish secure communication between enrolling devices and the CA. It supports both initial certificate enrollment for new devices and certificate renewal for existing devices that are approaching expiration.
Let's take a look at how it works as a step-by-step process:
First the device, usually managed by a mobile device management system, that requires a certificate, establishes communication with the SCEP server via HTTP/HTTPS using the SCEP server's URL to obtain its capabilities including which cryptographic algorithms, message types, and features the CA supports. This happens by means of a GetCACaps request. The process ensures compatibility between the enrolling device and the CA before proceeding with enrollment.
Once compatibility is established, the device then sends a GetCACert request to the SCEP server and retrieves a copy of the public certificate/root certificate of the CA. This will be used to encrypt sensitive information in subsequent communications and validate responses from the CA.
The enrolling device then locally creates a public-private key pair and creates a certificate signing request which contains its public key and identifying information. The device then encrypts this using the SCEP server/CA's public key and sends it to the CA.
Upon receiving the certificate signing request, the CA validates the authenticity of the request by verifying the signature and decrypting the message. The CA then performs identity validation according to its certificate policy, which may include checking preshared secrets and validating device credentials.
If the request passes all required validation checks, the CA issues a digital certificate signed with its private key, binding the device's public key to its identity. The CA then wraps the signed certificate in a PKCS#7 format message encrypted with the device's public key to ensure only the specific requesting device can access it.
Once the certificate is issued, the device retrieves the PKCS#7 response, decrypts it using its private key, extracts the signed certificate, and installs it in the appropriate certificate store.
As the certificate approaches its expiry date, SCEP-enabled devices can automatically initiate the renewal process by generating a new CSR and submitting it through the same SCEP workflow. This ensures continuous certificate validity without manual intervention, which is particularly crucial for certificates with shorter lifespans.
Why is SCEP essential
The SCEP helps improve your certificate management in three core areas:
- 01.
Automation
SCEP eliminates repetitive manual certificate life cycle management tasks from certificate request through to deployment and renewal. This reduces time to create and deploy to a matter of minutes, reducing the administrative burden on IT teams, and eliminating manual errors.
- 02.
Scalability
With the SCEP protocol, your organization can manage certificate issuance and renewal for thousands of devices efficiently. As certificate lifespans reduce and the volume of certificates in the organization multiplies, SCEP helps ensure that they are efficiently managed across systems, whether they are on-premises, cloud, or IoT devices.
- 03.
Security
With being both scalable and automatic, SCEP ensures consistent certificate deployment in volume and in-line with organizational security policies. Further, the automated process reduces human errors that could lead to misconfigurations, weak cryptographic settings, or expired certificates, strengthening overall security, and preventing certificate related mishaps.
Common SCEP use-cases
- 01.
Mobile device management (MDM) systems
Organizations deploying mobile device management solutions use SCEP extensively to provision certificates to smartphones, tablets, and laptops, enabling them to connect securely to the enterprise network, systems, and applications. When a device enrolls in an MDM system, SCEP automatically delivers certificates for Wi-Fi authentication, VPN access, email encryption, app security, and more, ensuring devices are immediately secure upon enrollment.
- 02.
IoT devices
As the number of interconnected IoT devices grows exponentially, SCEP provides a scalable and secure method for provisioning unique identities to these devices at scale, preventing blind spots. These devices leverage SCEP to obtain certificates during manufacturing or initial deployment. This includes devices such as industrial control systems, smart building devices, automated mechatronics devices, medical equipment, connected vehicles, and more.
- 03.
Network devices
Network devices such as routers, switches, firewalls, and other network devices use SCEP to automatically obtain certificates for inter-device communication. This automation is particularly valuable in large networks where manually configuring certificates on thousands of network devices would be time-consuming and operationally taxing.
The role of certificate life cycle management solutions like Key Manager Plus
Although SCEP helps with automation of certificate delivery and renewal for devices, organizations need an adjacent certificate management platform to have complete visibility into all x.509 certificates including their SCEP-enrolled device certificates, as well as be able to manage them from a central console. ManageEngine Key Manager Plus helps with exactly this and more.
Key Manager Plus, ManageEngine's comprehensive certificate life cycle management platform helps organizations implement and manage x.509 certificates at scale, integrating seamlessly with all major certificate authorities while offering centralized visibility into all digital certificates. Further, Key Manager Plus provides automated certificate life cycle management options for both public and private x.509 certificates, provides comprehensive audit trails, and proactive expiry notifications, helping you truly unify the management of all your digital certificates.