#define SHORT_DATA ((const unsigned char *) "Sparkling water")#define SHORT_DATA_LEN 15unsigned char hash[crypto_shorthash_BYTES];unsigned char key[crypto_shorthash_KEYBYTES];crypto_shorthash_keygen(key);crypto_shorthash(hash, SHORT_DATA, SHORT_DATA_LEN, key);
Many applications and programming language implementations were recently found to be vulnerable to denial-of-service attacks when a hash function with weak security guarantees, such as Murmurhash 3, was used to construct a hash table.
In order to address this, Sodium provides the
crypto_shorthash() function, which outputs short but unpredictable (without knowing the secret key) values suitable for picking a list in a hash table for a given key.
This function is optimized for short inputs.
The output of this function is only 64 bits. Therefore, it should not be considered collision-resistant.
Probabilistic data structures such as Bloom filters
Integrity checking in interactive protocols
int crypto_shorthash(unsigned char *out, const unsigned char *in,unsigned long long inlen, const unsigned char *k);
Compute a fixed-size (
crypto_shorthash_BYTES bytes) fingerprint for the message
in whose length is
inlen bytes, using the key
crypto_shorthash_KEYBYTES bytes and can be created using
The same message hashed with the same key will always produce the same output.
The key has to remain secret. This function will not provide any mitigations
against DoS attacks if the key is known from attackers.
When building hash tables, it is recommended to use a prime number for the
table size. This ensures that all bits from the output of the hash function
are being used. Mapping the range of the hash function to
[0..N) can be done
libsodium >= 1.0.12 also implements a variant of SipHash with the same key
size but a 128-bit output, accessible as