DTLS PSK demo

DTLS 1.2/1.3 PSK handshake demo.

Runs an in-process DTLS server and client with PSK. Optional arguments: --chacha use ChaCha20-Poly1305; --aes use AES-GCM; 1.2 or 12 for DTLS 1.2; 1.3 or 13 for DTLS 1.3. Default is AES-GCM and DTLS 1.2.

DTLS PSK Demo

This demo exercises the DTLS 1.2/1.3 handshake plumbing with PSK. It is intended as a functional smoke test and a starting point for interop checks.

Build

• Configure and build the demo target via the top-level CMake.
• The target name is dtls_psk_demo.

Interop Test Hooks (OpenSSL) The demo itself does not open sockets; it is a logic-level handshake example. For wire-level interop, use the library in your own UDP transport and verify against OpenSSL:

DTLS 1.2 server (OpenSSL): openssl s_server -dtls1_2 -psk 0102030405060708 -psk_identity test -cipher PSK-AES128-CCM8 -accept 4444

DTLS 1.2 client (OpenSSL): openssl s_client -dtls1_2 -psk 0102030405060708 -psk_identity test -cipher PSK-AES128-CCM8 -connect 127.0.0.1:4444

DTLS 1.3 server (OpenSSL 3.x): openssl s_server -dtls1_3 -psk 0102030405060708 -psk_identity test -ciphersuites TLS_AES_128_GCM_SHA256 -accept 4444

DTLS 1.3 client (OpenSSL 3.x): openssl s_client -dtls1_3 -psk 0102030405060708 -psk_identity test -ciphersuites TLS_AES_128_GCM_SHA256 -connect 127.0.0.1:4444

Runtime cipher preference (TLS/DTLS 1.3)

• dtls_psk_demo --chacha [1.2|1.3] — prefer ChaCha20-Poly1305.
• dtls_psk_demo --aes [1.2|1.3] — prefer AES-GCM (default). When using the full handshake API (tls13_context_t, tls13_connect / tls13_accept), call tls13_set_prefer_chacha20(ctx, 1) before the handshake to prefer ChaCha, or tls13_set_prefer_chacha20(ctx, 0) for AES-GCM.

DTLS Configuration APIs The DTLS context exposes tuning functions (timeouts, MTU, ACK ranges, anti-amplification limits). See noxtls-lib/tls/noxtls_dtls_common.h.

Examples

dtls_psk_demo dtls_psk_demo 1.3 dtls_psk_demo --chacha 1.2 dtls_psk_demo --aes 1.3