/*
* Public Key Work Factor Functions
* (C) 1999-2007 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#ifndef BOTAN_WORKFACTOR_H__
#define BOTAN_WORKFACTOR_H__

#include <botan/types.h>

namespace Botan {

/**
* Estimate work factor for discrete logarithm
* @param prime_group_size size of the group in bits
* @return estimated security level for this group
*/
BOTAN_DLL size_t dl_work_factor(size_t prime_group_size);

/**
* Return the appropriate exponent size to use for a particular prime
* group. This is twice the size of the estimated cost of breaking the
* key using an index calculus attack; the assumption is that if an
* arbitrary discrete log on a group of size bits would take about 2^n
* effort, and thus using an exponent of size 2^(2*n) implies that all
* available attacks are about as easy (as e.g Pollard's kangaroo
* algorithm can compute the DL in sqrt(x) operations) while minimizing
* the exponent size for performance reasons.
*/
BOTAN_DLL size_t dl_exponent_size(size_t prime_group_size);

/**
* Estimate work factor for integer factorization
* @param n_bits size of modulus in bits
* @return estimated security level for this modulus
*/
BOTAN_DLL size_t if_work_factor(size_t n_bits);

/**
* Estimate work factor for EC discrete logarithm
* @param prime_group_size size of the group in bits
* @return estimated security level for this group
*/
BOTAN_DLL size_t ecp_work_factor(size_t prime_group_size);

}

#endif