BN_num_bytes man page on Syllable

Man page or keyword search:  
man Server   2339 pages
apropos Keyword Search (all sections)
Output format
Syllable logo
[printable version]

BN_num_bytes(3)			    OpenSSL		       BN_num_bytes(3)

NAME
       BN_num_bits, BN_num_bytes, BN_num_bits_word - get BIGNUM size

SYNOPSIS
	#include <openssl/bn.h>

	int BN_num_bytes(const BIGNUM *a);

	int BN_num_bits(const BIGNUM *a);

	int BN_num_bits_word(BN_ULONG w);

DESCRIPTION
       BN_num_bytes() returns the size of a BIGNUM in bytes.

       BN_num_bits_word() returns the number of significant bits in a word.
       If we take 0x00000432 as an example, it returns 11, not 16, not 32.
       Basically, except for a zero, it returns floor(log2(w))+1.

       BN_num_bits() returns the number of significant bits in a BIGNUM,
       following the same principle as BN_num_bits_word().

       BN_num_bytes() is a macro.

RETURN VALUES
       The size.

NOTES
       Some have tried using BN_num_bits() on individual numbers in RSA keys,
       DH keys and DSA keys, and found that they don't always come up with the
       number of bits they expected (something like 512, 1024, 2048, ...).
       This is because generating a number with some specific number of bits
       doesn't always set the highest bits, thereby making the number of
       significant bits a little lower.	 If you want to know the "key size" of
       such a key, either use functions like RSA_size(), DH_size() and
       DSA_size(), or use BN_num_bytes() and multiply with 8 (although there's
       no real guarantee that will match the "key size", just a lot more
       probability).

SEE ALSO
       bn(3), DH_size(3), DSA_size(3), RSA_size(3)

HISTORY
       BN_num_bytes(), BN_num_bits() and BN_num_bits_word() are available in
       all versions of SSLeay and OpenSSL.

0.9.8k				  2004-07-01		       BN_num_bytes(3)
[top]
                             _         _         _ 
                            | |       | |       | |     
                            | |       | |       | |     
                         __ | | __ __ | | __ __ | | __  
                         \ \| |/ / \ \| |/ / \ \| |/ /  
                          \ \ / /   \ \ / /   \ \ / /   
                           \   /     \   /     \   /    
                            \_/       \_/       \_/ 
More information is available in HTML format for server Syllable

List of man pages available for Syllable

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
....................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net