SSL_GET_FINISHED(3)

💅 SSL_GET_FINISHED(3) 💅

okay so bestie, welcome to the Library Functions Manual for libssl — yes the crypto one, come on in 🫶

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✨ NAME ✨

SSL_get_finished, SSL_get_peer_finished — grab the last finished message that got sent, or the last one you're expecting 👀

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🌸 SYNOPSIS 🌸

library “libssl” libcrypto #include <openssl/ssl.h>

size_t
SSL_get_finished(const SSL *ssl, void *buf, size_t count);

size_t
SSL_get_peer_finished(const SSL *ssl, void *buf, size_t count);

literally just two functions, both returning size_t, both taking an const SSL *ssl, a void *buf and a size_t count. iconic signature, no notes 💅

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🦋 DESCRIPTION 🦋

okay so here's the vibe: SSL_get_finished() and SSL_get_peer_finished() copy count bytes into the caller-provided buffer buf 💖 and where do those bytes come from? glad you asked bestie:

• SSL_get_finished() — from the last finished message sent to the peer
• SSL_get_peer_finished() — from the last finished message expected from the peer

and like, what even is the finished message? ngl it's kind of the main character of the handshake — it's computed from a checksum of the handshake records exchanged with the peer 🔥. its length depends on the ciphersuite in use, and it's at most EVP_MAX_MD_SIZE, i.e., 64 bytes. that's the ceiling, bestie, don't come for it 🎀

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⭐ RETURN VALUES ⭐

both functions return the number of bytes copied into buf 🫶.

the return value is zero if the handshake has not reached the finished message — so if you get 0, that handshake said "not yet" and honestly same 😭

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🌈 SEE ALSO 🌈

• ssl(3)
• SSL_get_session(3)
• SSL_set_session(3)

go read those too, iykyk 📚✨

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🎀 STANDARDS 🎀

• RFC 9846: The Transport Layer Security (TLS) Protocol Version 1.3, section 4.5.3: Finished.
• RFC 5246: The Transport Layer Security (TLS) Protocol Version 1.2, section 7.4.9: Finished.

like yes, both versions, we contain multitudes 💜

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👑 HISTORY 👑

SSL_get_finished() and SSL_get_peer_finished() first appeared in SSLeay 0.9.5 and have been available since OpenBSD 2.7 — absolute elders, they've been slaying since before we were born 🙈🕰️

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okay that's the whole page bestie, no cap 🧚

sign-off szn: this one's from Debian, dated August 21, 2026, and it's SSL_GET_FINISHED(3) — periodt 💅💖