ZDIGEST(3)

✨ ZDIGEST ✨

okay bestie, sit down, hydrate, and let me tell you about zdigest 💖 — it's the hashing class from the CZMQ Manual, and it's genuinely so good at what it does.

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🌸 NAME 🌸

zdigest — a class that provides hashing functions (SHA-1 at present). no cap, that's the whole job 💅

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🎀 SYNOPSIS 🎀

//  This is a stable class, and may not change except for emergencies. It
//  is provided in stable builds.
//  Constructor - creates new digest object, which you use to build up a
//  digest by repeatedly calling zdigest_update() on chunks of data.
CZMQ_EXPORT zdigest_t *
    zdigest_new (void);

//  Destroy a digest object
CZMQ_EXPORT void
    zdigest_destroy (zdigest_t **self_p);

//  Add buffer into digest calculation
CZMQ_EXPORT void
    zdigest_update (zdigest_t *self, const byte *buffer, size_t length);

//  Return final digest hash data. If built without crypto support,
//  returns NULL.
CZMQ_EXPORT const byte *
    zdigest_data (zdigest_t *self);

//  Return final digest hash size
CZMQ_EXPORT size_t
    zdigest_size (zdigest_t *self);

//  Return digest as printable hex string; caller should not modify nor
//  free this string. After calling this, you may not use zdigest_update()
//  on the same digest. If built without crypto support, returns NULL.
CZMQ_EXPORT char *
    zdigest_string (zdigest_t *self);

//  Self test of this class.
CZMQ_EXPORT void
    zdigest_test (bool verbose);

🫶 heads up: the source file is asking for a favor — Please add '@interface' section in './../src/zdigest.c'. so like, if that's your thing, go off.

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🦋 DESCRIPTION 🦋

okay so the zdigest class generates a hash from zchunks of data. the current algorithm is SHA-1, and the reason is literally just speed ⚡ — the goal is generating a unique digest for a file, and there are no security issues in this use case. so it's giving "fast and unbothered," not "cryptographically dramatic."

the current code depends on OpenSSL, which might be replaced by a hard coded SHA-1 implementation to reduce build dependencies. so watch that space, bestie 👀

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🌈 EXAMPLE 🌈

this one's straight from the zdigest_test method, so you know it works:

byte *buffer = (byte *) zmalloc (1024);
memset (buffer, 0xAA, 1024);

zdigest_t *digest = zdigest_new ();
assert (digest);
zdigest_update (digest, buffer, 1024);
const byte *data = zdigest_data (digest);
assert (data [0] == 0xDE);
assert (data [1] == 0xB2);
assert (data [2] == 0x38);
assert (data [3] == 0x07);
assert (streq (zdigest_string (digest),
               "DEB23807D4FE025E900FE9A9C7D8410C3DDE9671"));
zdigest_destroy (&digest);
freen (buffer);

#if defined (__WINDOWS__)
zsys_shutdown();
#endif

like look at that hex string. DEB23807D4FE025E900FE9A9C7D8410C3DDE9671. iconic behavior fr fr 👑

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💜 AUTHORS 💜

the czmq manual was written by the authors in the AUTHORS file. (yes, those authors. the ones in the file. love that for them.)

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⭐ RESOURCES ⭐

• main web site: (yes bestie, it's listed, and it is blank. we move.)
• report bugs to the email <zeromq-dev@lists.zeromq.org[1]>

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👑 COPYRIGHT 👑

Copyright (c) the Contributors as noted in the AUTHORS file. this file is part of CZMQ, the high-level C binding for 0MQ: http://czmq.zeromq.org. this Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. if a copy of the MPL was not distributed with this file, you can obtain one at http://mozilla.org/MPL/2.0/. LICENSE included with the czmq distribution.

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📝 NOTES 📝

1. zeromq-dev@lists.zeromq.org mailto:zeromq-dev@lists.zeromq.org

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and that's the whole page, bestie 💖 this was CZMQ 4.2.1, dated 01/16/2026 — so go forth, hash responsibly, and remember: it's giving SHA-1, not it's giving secure. mwah 🎀✨