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Use meaningful variable names in shorthash demo

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Frank Denis 2015-05-27 17:17:36 +02:00
parent 3eef43eead
commit a14dc377bf
1 changed files with 31 additions and 13 deletions
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44
demos/shorthash.c
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@ -11,30 +11,48 @@
#include "utils.h" /* utility functions shared by demos */
/*
* Short hash is a fast algorithm intended for hash tables and anything
* else that does not require data integrity. There is the added benefit
* of a key which will alter the output of the hash.
* 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.
*
* Use cases:
*
* - Hash tables
* - Probabilistic data structures such as Bloom filters
* - Integrity checking in interactive protocols
*/
void
shorthash(void)
{
unsigned char k[crypto_shorthash_KEYBYTES]; /* key */
unsigned char h[crypto_shorthash_BYTES]; /* hash output */
unsigned char m[MAX_INPUT_SIZE]; /* message */
size_t mlen; /* length */
unsigned char key[crypto_shorthash_KEYBYTES];
unsigned char hash[crypto_shorthash_BYTES];
unsigned char message[MAX_INPUT_SIZE];
size_t message_len;
puts("Example: crypto_shorthash\n");
memset(k, 0, sizeof k);
prompt_input("Input your key > ", (char*)k, sizeof k);
memset(key, 0, sizeof key);
prompt_input("Enter a key > ", (char*)key, sizeof key);
mlen = prompt_input("Input your message > ", (char*)m, sizeof m);
message_len = prompt_input("Enter a message > ",
(char*)message, sizeof message);
putchar('\n');
printf("Hashing message with %s\n", crypto_shorthash_primitive());
crypto_shorthash(h, m, mlen, k);
printf("Hashing the message with %s\n", crypto_shorthash_primitive());
crypto_shorthash(hash, message, message_len, key);
fputs("Hash: ", stdout);
print_hex(h, sizeof h);
print_hex(hash, sizeof hash);
putchar('\n');
putchar('\n');
}