Let's Encrypt vs ArcSight: What are the differences?
Let's Encrypt: A free, automated, and open Certificate Authority (CA). It is a free, automated, and open certificate authority brought to you by the non-profit Internet Security Research Group (ISRG); ArcSight: Next-Gen Security Operations. Real-time threat detection, machine-learning analytics, and SOAR integrations to minimize exposure to threats.
Let's Encrypt and ArcSight are primarily classified as "Certificate Authority" and "Security" tools respectively.