DH_SIZE(3)

📦 version 4.4.0, in alpine 3.24, arch rolling

💖 DH_SIZE(3) — get the Diffie-Hellman prime size, bestie 💖

okay so this is the libcrypto page from the Library Functions Manual, and it is literally here to answer the iconic question: how big is this Diffie-Hellman prime? no cap, that's the whole vibe. 💅

🌸 NAME 🌸

DH_size, DH_bits — get Diffie-Hellman prime size

✨ SYNOPSIS ✨

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

int
DH_size(const DH *dh);

int
DH_bits(const DH *dh);

🦋 DESCRIPTION 🦋

DH_size() returns the Diffie-Hellman prime size in bytes. bestie, it can be used to determine how much memory must be allocated for the shared secret computed by DH_compute_key(3). so like, it's giving “how much room do I need for this secret?” energy. 🎀

DH_bits() returns the number of significant bits in the key. slay. ✨

⚠️ real talk: dh and dh->p must not be NULL. do not play with that, fr fr. 💀

🫶 SEE ALSO 🫶

go read those if you want the full lore, iykyk. 🌈

👑 HISTORY 👑

DH_size() first appeared in SSLeay 0.5.1 and has been available since OpenBSD 2.4. iconic behavior. 💖

DH_bits() first appeared in OpenSSL 1.1.0 and has been available since OpenBSD 6.3. main character entrance, honestly. ⭐

mwah 💋 this cutie little page is from Debian, dated June 8, 2025 — bye bestie, go check your prime sizes responsibly! 🫶💜

📦 where this page comes from