Cisco Cloudlock is a Cloud Access Security Broker (CASB) that operates as an API-based broker to secure cloud environments. It integrates directly with Software-as-a-Service (SaaS), Infrastructure-as-a-Service (IaaS), and Platform-as-a-Service (PaaS) applications via their APIs. This allows Cloudlock to discover and control cloud applications, monitor user behavior for anomalies, and enforce data loss prevention (DLP) policies to protect sensitive data. Its core function is to reduce application risks and prevent data breaches in cloud services, which are by definition "not on-premise."

B. Cisco Umbrella: This is a Secure Internet Gateway (SIG) that provides DNS-layer security and a secure web gateway; it is not primarily an API-based broker for cloud application security.
C. Cisco AMP: Now called Cisco Secure Endpoint, this is an endpoint protection (EPP) and detection/response (EDR) solution focused on protecting devices like laptops and servers from malware.
D. Cisco AppDynamics: This is an Application Performance Monitoring (APM) and observability platform used to monitor the health and performance of applications, not primarily for security enforcement.

1. Cisco Cloudlock At-a-Glance: "Cisco Cloudlock is a cloud-native Cloud Access Security Broker (CASB) that helps accelerate your safe cloud adoption. Cloudlock secures your cloud users, data, and applications..." It further explains its API-based approach for protecting platforms like Office 365, G Suite, and Salesforce. (Cisco, "Cisco Cloudlock At-a-Glance," Document C45-737222-04, Page 1).

2. Cisco Cloudlock Data Sheet: "As a cloud-native CASB, Cloudlock has a 100 percent cloud-based, API-driven architecture that provides fast, flexible, and easy deployment." This statement directly confirms its identity as an API-based broker for cloud environments. (Cisco, "Cisco Cloudlock Data Sheet," Document C78-737221-07, Page 2, "Product architecture" section).

3. Cisco SAFE for Cloud Security Reference Guide: This guide positions the different Cisco security products. It describes Cloudlock's role: "Cisco Cloudlock (CASB) provides visibility and control over user activity and sensitive data in cloud applications." It contrasts this with Umbrella's role in securing internet access and AMP's role in endpoint protection. (Cisco, "SAFE for Cloud Security Reference Guide," Version 2.0, Page 11, "Cloud Security Capabilities" section).