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/*
* KDF defined in NIST SP 800-56a revision 2 (Single-step key-derivation function)
*
* (C) 2017 Ribose Inc. Written by Krzysztof Kwiatkowski.
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_SP800_56A_H_
#define BOTAN_SP800_56A_H_
#include <botan/kdf.h>
#include <botan/hash.h>
#include <botan/mac.h>
BOTAN_FUTURE_INTERNAL_HEADER(sp800_56a.h)
namespace Botan {
/**
* NIST SP 800-56A KDF using hash function
* @warning This KDF ignores the provided salt value
*/
class BOTAN_PUBLIC_API(2,2) SP800_56A_Hash final : public KDF
{
public:
std::string name() const override { return "SP800-56A(" + m_hash->name() + ")"; }
KDF* clone() const override { return new SP800_56A_Hash(m_hash->clone()); }
/**
* Derive a key using the SP800-56A KDF.
*
* The implementation hard codes the context value for the
* expansion step to the empty string.
*
* @param key derived keying material K_M
* @param key_len the desired output length in bytes
* @param secret shared secret Z
* @param secret_len size of Z in bytes
* @param salt ignored
* @param salt_len ignored
* @param label label for the expansion step
* @param label_len size of label in bytes
*
* @throws Invalid_Argument key_len > 2^32
*/
size_t kdf(uint8_t key[], size_t key_len,
const uint8_t secret[], size_t secret_len,
const uint8_t salt[], size_t salt_len,
const uint8_t label[], size_t label_len) const override;
/**
* @param hash the hash function to use as the auxiliary function
*/
explicit SP800_56A_Hash(HashFunction* hash) : m_hash(hash) {}
private:
std::unique_ptr<HashFunction> m_hash;
};
/**
* NIST SP 800-56A KDF using HMAC
*/
class BOTAN_PUBLIC_API(2,2) SP800_56A_HMAC final : public KDF
{
public:
std::string name() const override { return "SP800-56A(" + m_mac->name() + ")"; }
KDF* clone() const override { return new SP800_56A_HMAC(m_mac->clone()); }
/**
* Derive a key using the SP800-56A KDF.
*
* The implementation hard codes the context value for the
* expansion step to the empty string.
*
* @param key derived keying material K_M
* @param key_len the desired output length in bytes
* @param secret shared secret Z
* @param secret_len size of Z in bytes
* @param salt ignored
* @param salt_len ignored
* @param label label for the expansion step
* @param label_len size of label in bytes
*
* @throws Invalid_Argument key_len > 2^32 or MAC is not a HMAC
*/
size_t kdf(uint8_t key[], size_t key_len,
const uint8_t secret[], size_t secret_len,
const uint8_t salt[], size_t salt_len,
const uint8_t label[], size_t label_len) const override;
/**
* @param mac the HMAC to use as the auxiliary function
*/
explicit SP800_56A_HMAC(MessageAuthenticationCode* mac);
private:
std::unique_ptr<MessageAuthenticationCode> m_mac;
};
}
#endif