Random number generator (device): Difference between revisions
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if (r == NULL) |
if (r == NULL) |
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{ |
{ |
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perror("/dev/urandom"); |
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return 1; |
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} |
} |
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if (br < 1) |
if (br < 1) |
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{ |
{ |
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fputs("/dev/urandom: Not enough bytes\n", stderr); |
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return 1; |
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} |
} |
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[http://www.openbsd.org/cgi-bin/man.cgi?query=arc4random&apropos=0&sektion=3&manpath=OpenBSD+Current&arch=i386&format=html arc4random()] appeared in [[OpenBSD]] 2.1 and has spread to many [[BSD]] systems. This function runs an ARC4 random number generator that takes entropy from a kernel device. (This kernel device is sysctl kern.arandom in OpenBSD, or /dev/urandom in some other systems.) |
[http://www.openbsd.org/cgi-bin/man.cgi?query=arc4random&apropos=0&sektion=3&manpath=OpenBSD+Current&arch=i386&format=html arc4random()] appeared in [[OpenBSD]] 2.1 and has spread to many [[BSD]] systems. This function runs an ARC4 random number generator that takes entropy from a kernel device. (This kernel device is sysctl kern.arandom in OpenBSD, or /dev/urandom in some other systems.) |
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<lang c>#include <inttypes.h> |
<lang c>#include <inttypes.h> /* PRIu32 */ |
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#include <stdlib.h> |
#include <stdlib.h> /* arc4random */ |
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#include <stdio.h> |
#include <stdio.h> /* printf */ |
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int |
int |
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main() |
main() |
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{ |
{ |
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printf("%" PRIu32 "\n", arc4random()); |
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return 0; |
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}</lang> |
}</lang> |
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main() |
main() |
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{ |
{ |
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uint32_t v; |
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if (RAND_bytes((unsigned char *)&v, sizeof v) == 0) { |
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ERR_print_errors_fp(stderr); |
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return 1; |
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} |
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printf("%" PRIu32 "\n", v); |
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return 0; |
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}</lang> |
}</lang> |
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{{works with|MinGW}} |
{{works with|MinGW}} |
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<lang c>#include <stdio.h> |
<lang c>#include <stdio.h> /* printf */ |
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#include <windows.h> |
#include <windows.h> |
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#include <wincrypt.h> |
#include <wincrypt.h> /* CryptAcquireContext, CryptGenRandom */ |
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int |
int |
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main() |
main() |
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{ |
{ |
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HCRYPTPROV p; |
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ULONG i; |
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if (CryptAcquireContext(&p, NULL, NULL, |
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PROV_RSA_FULL, CRYPT_VERIFYCONTEXT) == FALSE) { |
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fputs("CryptAcquireContext failed.\n", stderr); |
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return 1; |
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} |
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if (CryptGenRandom(p, sizeof i, (BYTE *)&i) == FALSE) { |
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fputs("CryptGenRandom failed.\n", stderr); |
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return 1; |
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} |
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printf("%lu\n", i); |
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CryptReleaseContext(p, 0); |
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return 0; |
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}</lang> |
}</lang> |
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public class RandomExample { |
public class RandomExample { |
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public static void main(String[] args) { |
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SecureRandom rng = new SecureRandom(); |
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/* Prints a random signed 32-bit integer. */ |
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System.out.println(rng.nextInt()); |
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} |
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}</lang> |
}</lang> |
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bytes <- getEntropy 4 |
bytes <- getEntropy 4 |
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print (runGet getWord32be $ B.fromChunks [bytes])</lang> |
print (runGet getWord32be $ B.fromChunks [bytes])</lang> |
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=={{header|Lasso}}== |
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<lang lasso>file(`/dev/urandom`)->readSomeBytes(4)->export32bits</lang> |
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{{out}} |
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<pre>723217350</pre> |
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=={{header|NetRexx}}== |
=={{header|NetRexx}}== |
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