TLS and Certificates

TLS versions, handshake, SNI, certificate types and ACME.

• What is the difference between SSL and TLS?GEN-04-001
• What is an SSL/TLS certificate?GEN-04-002
• What is a Private Key?GEN-04-003
• What is a CA (Certificate Authority)?GEN-04-004
• What is a wildcard certificate?GEN-04-005
• What is the difference between the TLS versions (TLS 1.0, 1.1, 1.2, 1.3)?GEN-04-006
• What is the TLS handshake?GEN-04-007
• What is a cipher suite?GEN-04-008
• What is SNI (Server Name Indication)?GEN-04-009
• What is HSTS?GEN-04-010
• What is mTLS?GEN-04-011
• What is the difference between RSA and ECDSA keys?GEN-04-012
• What is a certificate chain?GEN-04-013
• What is the difference between a root CA and an intermediate CA?GEN-04-014
• What is a self-signed certificate?GEN-04-015
• What is a CSR (Certificate Signing Request)?GEN-04-016
• What are the CN and SAN fields in a certificate?GEN-04-017
• What is the difference between the PEM and PFX certificate formats?GEN-04-018
• What is a certificate fingerprint?GEN-04-019
• What is PKI (Public Key Infrastructure)?GEN-04-020
• What are the ACME protocol and Let's Encrypt?GEN-04-021
• What are Perfect Forward Secrecy (PFS) and ECDHE?GEN-04-022
• What is Post-quantum Key Exchange?GEN-04-023
• What is ALPN?GEN-04-024
• What is TLS session resumption?GEN-04-025
• What are OCSP and OCSP Stapling?GEN-04-026
• What is certificate revocation?GEN-04-027
• What is a Trust Anchor?GEN-04-028
• What is Extended Key Usage (EKU)?GEN-04-029
• What is AIA (Authority Information Access)?GEN-04-030
• What is EAB (External Account Binding) in ACME?GEN-04-031
• What is the difference between renewing a certificate and rekeying it?GEN-04-032
• What is the difference between STARTTLS and implicit TLS (SMTPS, LDAPS)?GEN-04-033