Problem - Kevin Tafuro

Additionally, you can ask for a random number with a specific number of bits:
int BN_rand(BIGNUM *result, int bits, int top, int bottom);
This function has the following arguments:
result
The generated random number will be stored in this BIGNUM object.
bits
Number of bits that the generated random number should contain.
top
If the value of this argument is 0, the most significant bit in the generated random
number will be set. If it is –1, the most significant bit can be anything. If it
is 1, the 2 most significant bits will be set. This is useful when you want to make
sure that the product of 2 numbers of a particular bit length will always have
exactly twice as many bits.
bottom
If the value of this argument is 1, the resulting random number will be odd. Otherwise,
it may be either odd or even.
Outputting BIGNUM objects
If you wish to represent your BIGNUM object as a binary number, you can use BN_
bn2bin( ), which will store the binary representation of the BIGNUM object in the buffer
pointed to by the outbuf argument:
int BN_bn2bin(BIGNUM *bn, unsigned char *outbuf);
Unfortunately, you first need to know in advance how big the output buffer needs to
be. You can learn this by calling BN_num_bytes( ), which has the following signature:
int BN_num_bytes(BIGNUM *bn);
BN_bn2bin( ) will not output the sign of a number. You can manually
query the sign of the number by using the following macro:
#define BN_is_negative(x) ((x)->neg)
The following is a wrapper that converts a BIGNUM object to binary, allocating its
result via malloc( ) and properly setting the most significant bit to 1 if the result is
negative. Note that you have to pass in a pointer to an unsigned integer. That integer
gets filled with the size of the returned buffer in bytes.
#include
#include
#define BN_is_negative(x) ((x)->neg)
unsigned char *BN_to_binary(BIGNUM *b, unsigned int *outsz) {
unsigned char *ret;
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