RFC 9325

Q: What does the Introduction section cover in RFC 9325 — TLS/DTLS Best Practices?

The Introduction section provides detailed technical specifications, security considerations, and implementation guidance as documented in RFC 9325 — TLS/DTLS Best Practices. This content is part of the BLACKLABS RFC Reference Library.

Q: What does the Protocol Version Recommendations section cover in RFC 9325 — TLS/DTLS Best Practices?

The Protocol Version Recommendations section provides detailed technical specifications, security considerations, and implementation guidance as documented in RFC 9325 — TLS/DTLS Best Practices. This content is part of the BLACKLABS RFC Reference Library.

Q: What does the Cipher Suite Recommendations section cover in RFC 9325 — TLS/DTLS Best Practices?

The Cipher Suite Recommendations section provides detailed technical specifications, security considerations, and implementation guidance as documented in RFC 9325 — TLS/DTLS Best Practices. This content is part of the BLACKLABS RFC Reference Library.

Q: What does the Certificate and Key Recommendations section cover in RFC 9325 — TLS/DTLS Best Practices?

The Certificate and Key Recommendations section provides detailed technical specifications, security considerations, and implementation guidance as documented in RFC 9325 — TLS/DTLS Best Practices. This content is part of the BLACKLABS RFC Reference Library.

Q: What does the Extension Recommendations section cover in RFC 9325 — TLS/DTLS Best Practices?

The Extension Recommendations section provides detailed technical specifications, security considerations, and implementation guidance as documented in RFC 9325 — TLS/DTLS Best Practices. This content is part of the BLACKLABS RFC Reference Library.

BLACKLABS

Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)

Best Current Practice Obsoletes: RFC 7525

November 2022

Abstract: This document provides recommendations for secure use of TLS and DTLS. It updates BCP 195 to cover TLS 1.3 and DTLS 1.3, specifying recommended protocol versions, cipher suites, extensions, and operational practices.

Canonical source: https://www.rfc-editor.org/rfc/rfc9325 | IETF Datatracker

1. Introduction

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BCP 195 (RFC 9325, obsoleting RFC 7525) provides security recommendations for TLS/DTLS deployments. 3GPP security specifications reference these best practices for operator network security profiles.

2. Protocol Version Recommendations

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Version	Recommendation	Notes
TLS 1.3	MUST	Preferred for all new deployments
TLS 1.2	MAY (with restrictions)	Only with AEAD cipher suites and ECDHE key exchange
TLS 1.1	MUST NOT	Deprecated
TLS 1.0	MUST NOT	Deprecated
SSL 3.0	MUST NOT	Broken (POODLE)
DTLS 1.3	MUST	For datagram-based protocols
DTLS 1.2	MAY (with restrictions)	Only with AEAD cipher suites

3. Cipher Suite Recommendations

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MUST: TLS_AES_128_GCM_SHA256, TLS_AES_256_GCM_SHA384 for TLS 1.3
SHOULD: TLS_CHACHA20_POLY1305_SHA256 for TLS 1.3
MUST NOT: Any cipher suite using RC4, DES, 3DES, EXPORT-grade, NULL, or static RSA key exchange
TLS 1.2 only: MUST use AEAD (GCM or CCM), MUST use ECDHE or DHE for forward secrecy
Compression: MUST NOT use TLS compression (CRIME attack)

4. Certificate and Key Recommendations

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RSA keys: Minimum 2048 bits, SHOULD use 3072+ bits
ECDSA keys: P-256 (secp256r1) minimum, SHOULD support P-384
Signature algorithms: MUST support ECDSA and RSA-PSS, MUST NOT use PKCS#1 v1.5 with TLS 1.3
Certificate validation: MUST verify full chain, check revocation (OCSP/CRL), validate SAN
Wildcard certificates: SHOULD be avoided in operator core network deployments

5. Extension Recommendations

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SNI: MUST send Server Name Indication for virtual hosting and certificate selection
ALPN: SHOULD use Application-Layer Protocol Negotiation (e.g., 'h2' for HTTP/2)
OCSP stapling: SHOULD support status_request extension for online certificate status
Session tickets: If used, MUST be encrypted with a key not derived from the connection
Renegotiation: N/A in TLS 1.3 (removed); in TLS 1.2 MUST use renegotiation_info

6. Operational Best Practices

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Disable TLS 1.0 and 1.1 entirely — not just deprioritize
Monitor certificate expiry and automate renewal (CMPv2/EST)
Use certificate pinning cautiously — can cause operational issues with CA rotation
Log TLS handshake failures for security monitoring
Implement proper session cache management to prevent memory exhaustion