RIPEMD(3)

📦
version 15.1 · 2 versions
, in freebsd 15.1

💅 RIPEMD(3) — the ripemd girlies are here

okay so bestie, welcome to the RIPEMD160 page, from the Library Functions Manual, and honestly it's a whole moment. no cap, it's giving "cryptographic fingerprint" energy and i'm obsessed. let me walk you through it 🎀

✨ NAME ✨

RIPEMD160_Init, RIPEMD160_Update, RIPEMD160_Final, RIPEMD160_End, RIPEMD160_Fd, RIPEMD160_FdChunk, RIPEMD160_File, RIPEMD160_FileChunk, RIPEMD160_Data — literally all of them, bestie, and their whole entire job is calculating the RIPEMD160 message digest 🦋

📚 LIBRARY 📚

Message Digest (MD4, MD5, etc.) Support Library — that's libmd, and you link it with -lmd 💖

🌸 SYNOPSIS 🌸

here's the part where you copy-paste, bestie. no shame.

#include <sys/types.h>
#include <ripemd.h>

void
RIPEMD160_Init(RIPEMD160_CTX *context);

void
RIPEMD160_Update(RIPEMD160_CTX *context, const unsigned char *data,
    unsigned int len);

void
RIPEMD160_Final(unsigned char digest[20], RIPEMD160_CTX *context);

char *
RIPEMD160_End(RIPEMD160_CTX *context, char *buf);

char *
RIPEMD160_Fd(int fd, char *buf);

char *
RIPEMD160_FdChunk(int fd, char *buf, off_t offset, off_t length);

char *
RIPEMD160_File(const char *filename, char *buf);

char *
RIPEMD160_FileChunk(const char *filename, char *buf, off_t offset,
    off_t length);

char *
RIPEMD160_Data(const unsigned char *data, unsigned int len, char *buf);

💜 DESCRIPTION 💜

so the RIPEMD160_ functions (all of them, collectively, they're a team 💅) calculate a 160-bit cryptographic checksum — a digest — for any number of input bytes. any. number. slay.

a cryptographic checksum is a one-way hash function, meaning it's computationally impractical to find the input that corresponds to a particular output. it just doesn't happen, bestie. the net result is basically a "fingerprint" of the input-data — and here's the iconic part — it does not disclose the actual input. the math ate and left no crumbs 🔥

🌈 the core trio 🌈

RIPEMD160_Init(), RIPEMD160_Update(), and RIPEMD160_Final() are the core functions. the whole ritual is:

  1. Allocate an RIPEMD160_CTX
  2. Initialize it with RIPEMD160_Init()
  3. Run over the data with RIPEMD160_Update()
  4. Finally extract the result using RIPEMD160_Final()

and plot twist — RIPEMD160_Final() will also erase the RIPEMD160_CTX. it cleans up after itself. main character energy honestly 💅

✨ the wrapper squad ✨

  • RIPEMD160_End() — a wrapper for RIPEMD160_Final() which converts the return value to a 41-character (including the terminating '\0') ASCII string, representing the 160 bits in hexadecimal 🐝
  • RIPEMD160_File() — calculates the digest of a file, and uses RIPEMD160_End() to return the result. if the file cannot be opened, a null pointer is returned 😭
  • RIPEMD160_FileChunk() — similar to RIPEMD160_File(), but it only calculates the digest over a byte-range of the file specified, starting at offset and spanning length bytes. and get this: if the length parameter is specified as 0, or more than the length of the remaining part of the file, RIPEMD160_FileChunk() calculates the digest from offset to the end of file. it just keeps going. iconic 🎀
  • RIPEMD160_Data() — calculates the digest of a chunk of data in memory, and uses RIPEMD160_End() to return the result 💖
  • RIPEMD160_Fd() and RIPEMD160_FdChunk() — identical to their RIPEMD160_File() and RIPEMD160_FileChunk() counterparts, with the exception that the first argument is an fd instead of a filename. same vibe, different door 🚪
🫶 buf tea, listen up bestie: when you're using RIPEMD160_End(), RIPEMD160_File(), or RIPEMD160_Data(), the buf argument can be a null pointer, in which case the returned string is allocated with malloc(3) and subsequently must be explicitly deallocated using free(3) after use. don't forget, or that's a leak, and leaks are not the vibe. if the buf argument is non-null it must point to at least 41 characters of buffer space. 41. not 40. 🔥

😭 ERRORS 😭

the RIPEMD160_End() function called with a null buf argument may fail and return NULL if:

  • [ENOMEM] — insufficient storage space is available 💀

and RIPEMD160_File() and RIPEMD160_FileChunk() may return NULL when underlying open(2), fstat(2), lseek(2), or RIPEMD160_End(3) fail. rough out here fr fr 🙈

🦋 SEE ALSO 🦋

the whole hash family, we love a supportive friend group 🌸

⭐ HISTORY ⭐

these functions appeared in FreeBSD 4.0. vintage. retro. lowkey a legacy queen 👑

👑 AUTHORS 👑

the core hash routines were implemented by Eric Young, based on the published RIPEMD160 specification. periodt. we stan 💜

💀 BUGS 💀

no method is known to exist which finds two files having the same hash value, nor to find a file with a specific hash value. however — and this is the part where you sit down — there is on the other hand no guarantee that such a method does not exist. 😭 the math is mathing but we stay humble 🧚

and that's the page, bestie ✨ this one's from the Debian edition, dated March 8, 2022 — go forth and hash responsibly, ily, mwah 💖🎀🦋

📦 where this page comes from