RIPEMD160(3)

💜 RIPEMD160(3) — like, the whole manual, bestie

okay so real talk: this is a page from the Library Functions Manual, and it's all about the RIPEMD-160 hash function. yes, that RIPEMD-160. she's iconic, she's 160 bits, she's got lore. let's get into it 🎀

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✨ NAME ✨

RIPEMD160, RIPEMD160_Init, RIPEMD160_Update, RIPEMD160_Final — the RIPEMD-160 hash function, aka the whole squad 💅

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🦋 SYNOPSIS 🦋

so you're gonna link against libcrypto and pull in the header, like:

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

then the functions themselves, one by one, no cap:

unsigned char *
RIPEMD160(const unsigned char *d, unsigned long n, unsigned char *md);

int
RIPEMD160_Init(RIPEMD160_CTX *c);

int
RIPEMD160_Update(RIPEMD160_CTX *c, const void *data, unsigned long len);

int
RIPEMD160_Final(unsigned char *md, RIPEMD160_CTX *c);

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🌸 DESCRIPTION 🌸

okay so RIPEMD-160 is a cryptographic hash function with a 160-bit output. that's the whole vibe. she takes your stuff and turns it into a fixed-size fingerprint ✨

RIPEMD160() computes the RIPEMD-160 message digest of the n bytes at d and plops it right into md. and md? bestie, md must have space for RIPEMD160_DIGEST_LENGTH == 20 bytes of output. twenty. not nineteen, not twenty-one. twenty 💀

but wait — what if your message isn't all cozy in memory at once? like, what if it's streaming? that's where these three come in:

• RIPEMD160_Init() — initializes a RIPEMD160_CTX structure. it's giving "set the stage" energy 👑
• RIPEMD160_Update() — can be called repeatedly with chunks of the message to be hashed (len bytes at data). feed her piece by piece, she doesn't mind 🍓
• RIPEMD160_Final() — places the message digest in md, which must have space for RIPEMD160_DIGEST_LENGTH == 20 bytes of output, and erases the RIPEMD160_CTX. she's done, she's out, she cleaned up after herself 🙈

✨ real one advice: applications should use the higher level functions EVP_DigestInit(3) etc. instead of calling the hash functions directly. like, go through the front door, not the window, iykyk.

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🔥 RETURN VALUES 🔥

• RIPEMD160() returns a pointer to the hash value. that's it, that's the return 💖
• RIPEMD160_Init(), RIPEMD160_Update(), and RIPEMD160_Final() return 1 for success or 0 otherwise. binary queen, no in-between 🌈

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👀 SEE ALSO 👀

go read these next, they're literally required reading:

• EVP_DigestInit(3)
• HMAC(3)

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⭐ STANDARDS ⭐

she's certified, she's official, she's got paperwork 📜

• ISO/IEC 10118-3:2004/Cor 1:2011
• Hash-functions — Part 3: Dedicated hash-functions
• Clause 7: RIPEMD-160

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🧚 HISTORY 🧚

RIPEMD160(), RIPEMD160_Init(), RIPEMD160_Update(), and RIPEMD160_Final() first appeared in SSLeay 0.9.0 and have been available since OpenBSD 2.4. ancient. legendary. still slaying 💀✨

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💀 CAVEATS 💀

okay so here's the tea, and it's important: other implementations allow md in RIPEMD160() to be NULL and return a static array — and that is not thread safe. so do not go assuming that's a thing here, bestie. not safe, not cute, don't do it 🙈

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aaaand that's the page! 🫶 this gorgeous chunk of documentation is from the Debian build, dated June 8, 2025 — so if you see RIPEMD160(3) floating around, now you know exactly what time it is. mwah 💋💜