What are the best practices for cloud security and zero-trust architecture?

Zero-trust architecture assumes no implicit trust: every request must be verified regardless of network location. Principles: verify explicitly (authenticate and authorize every access request), use least privilege access (grant minimum permissions needed), and assume breach (minimize blast radius, segment access, verify end-to-end encryption). Identity: implement centralized identity provider (Entra ID, Okta), enforce MFA for all users, use short-lived credentials (tokens expire in minutes/hours, not days), implement just-in-time access for privileged operations, and monitor for anomalous authentication patterns. Network: implement micro-segmentation (security groups/network policies restrict traffic between services), encrypt all traffic (mTLS between services, TLS 1.3 for external), implement private endpoints for cloud services (no public internet exposure), and use VPN or ZTNA (Zero Trust Network Access) for remote access. Data: classify data by sensitivity level, encrypt at rest (AES-256) and in transit, implement key management with rotation (AWS KMS, Azure Key Vault, HashiCorp Vault), apply access controls at the data layer (database RLS, object storage policies), and implement DLP (data loss prevention) for sensitive data. Application security: implement WAF (Web Application Firewall) for web applications, conduct regular penetration testing, scan dependencies for vulnerabilities (Snyk, Dependabot), implement runtime application self-protection (RASP), and use SBOM (Software Bill of Materials) for supply chain security. Monitoring: centralize security logs in SIEM (Splunk, Sentinel, Chronicle), implement automated threat detection, conduct regular security assessments, and maintain incident response playbooks. Compliance: implement continuous compliance monitoring, automate evidence collection for audits, and maintain documentation of security controls.