From 9acd2c86e00cbb8a1745296a47f57de9588cef57 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 13 May 2024 14:02:30 +0200 Subject: Merging upstream version 0.37. Signed-off-by: Daniel Baumann --- src/xor/xoroshiro256_prng.c | 74 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) create mode 100644 src/xor/xoroshiro256_prng.c (limited to 'src/xor/xoroshiro256_prng.c') diff --git a/src/xor/xoroshiro256_prng.c b/src/xor/xoroshiro256_prng.c new file mode 100644 index 0000000..defef88 --- /dev/null +++ b/src/xor/xoroshiro256_prng.c @@ -0,0 +1,74 @@ +/* + * XORoshiro-256 PRNG Implementation + * Author: Fabian Druschke + * Date: 2024-03-13 + * + * This is a XORoshiro-256 (XOR/rotate/shift/rotate) pseudorandom number generator + * implementation, designed for fast and efficient generation of high-quality + * pseudorandom numbers. XORoshiro-256 is part of the XORoshiro family of PRNGs known + * for their simplicity and excellent statistical properties for a wide range of + * applications, though they are not suitable for cryptographic purposes due to their + * predictability. + * + * As the author of this implementation, I, Fabian Druschke, hereby release this work into + * the public domain. I dedicate any and all copyright interest in this work to the public + * domain, making it free to use for anyone for any purpose without any conditions, unless + * such conditions are required by law. + * + * This software is provided "as is", without warranty of any kind, express or implied, + * including but not limited to the warranties of merchantability, fitness for a particular + * purpose, and noninfringement. In no event shall the authors be liable for any claim, + * damages, or other liability, whether in an action of contract, tort, or otherwise, arising + * from, out of, or in connection with the software or the use or other dealings in the software. + * + * Note: This implementation does not utilize OpenSSL or any cryptographic libraries, as + * XORoshiro-256 is not intended for cryptographic applications. It is crucial for applications + * requiring cryptographic security to use a cryptographically secure PRNG. + */ + +#include "xoroshiro256_prng.h" +#include +#include + +void xoroshiro256_init( xoroshiro256_state_t* state, uint64_t init_key[], unsigned long key_length ) +{ + // Initialization logic; ensure 256 bits are properly seeded + for( int i = 0; i < 4; i++ ) + { + if( i < key_length ) + { + state->s[i] = init_key[i]; + } + else + { + // Example fallback for insufficient seeds; consider better seeding strategies + state->s[i] = state->s[i - 1] * 6364136223846793005ULL + 1; + } + } +} + +static inline uint64_t rotl( const uint64_t x, int k ) +{ + return ( x << k ) | ( x >> ( 64 - k ) ); +} + +void xoroshiro256_genrand_uint256_to_buf( xoroshiro256_state_t* state, unsigned char* bufpos ) +{ + // This part of the code updates the state using xoroshiro256**'s algorithm. + const uint64_t result_starstar = rotl( state->s[1] * 5, 7 ) * 9; + const uint64_t t = state->s[1] << 17; + + state->s[2] ^= state->s[0]; + state->s[3] ^= state->s[1]; + state->s[1] ^= state->s[2]; + state->s[0] ^= state->s[3]; + + state->s[2] ^= t; + state->s[3] = rotl( state->s[3], 45 ); + + // Note: 'result_starstar' was only used for demonstration purposes and is not part of the + // original Xoroshiro256** specification. Here, we write the complete state into the buffer. + // Ensure that 'bufpos' has enough storage space (256 bits / 32 bytes). + + memcpy( bufpos, state->s, 32 ); // Copies the entire 256-bit (32 bytes) state into 'bufpos' +} -- cgit v1.2.3