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/*
* KDFs defined in NIST SP 800-108
* (C) 2016 Kai Michaelis
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/sp800_108.h>
#include <botan/loadstor.h>
#include <botan/exceptn.h>
#include <iterator>
namespace Botan {
size_t SP800_108_Counter::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
{
const std::size_t prf_len = m_prf->output_length();
const uint64_t blocks_required = (key_len + prf_len - 1) / prf_len;
if(blocks_required > 0xFFFFFFFF)
throw Invalid_Argument("SP800_108_Counter output size too large");
const uint8_t delim = 0;
const uint32_t length = static_cast<uint32_t>(key_len * 8);
uint8_t *p = key;
uint32_t counter = 1;
uint8_t be_len[4] = { 0 };
secure_vector<uint8_t> tmp;
store_be(length, be_len);
m_prf->set_key(secret, secret_len);
while(p < key + key_len)
{
const std::size_t to_copy = std::min< std::size_t >(key + key_len - p, prf_len);
uint8_t be_cnt[4] = { 0 };
store_be(counter, be_cnt);
m_prf->update(be_cnt,4);
m_prf->update(label,label_len);
m_prf->update(delim);
m_prf->update(salt,salt_len);
m_prf->update(be_len,4);
m_prf->final(tmp);
copy_mem(p, tmp.data(), to_copy);
p += to_copy;
++counter;
BOTAN_ASSERT(counter != 0, "No counter overflow");
}
return key_len;
}
size_t SP800_108_Feedback::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
{
const uint32_t length = static_cast<uint32_t>(key_len * 8);
const std::size_t prf_len = m_prf->output_length();
const std::size_t iv_len = (salt_len >= prf_len ? prf_len : 0);
const uint8_t delim = 0;
const uint64_t blocks_required = (key_len + prf_len - 1) / prf_len;
if(blocks_required > 0xFFFFFFFF)
throw Invalid_Argument("SP800_108_Feedback output size too large");
uint8_t *p = key;
uint32_t counter = 1;
uint8_t be_len[4] = { 0 };
secure_vector< uint8_t > prev(salt, salt + iv_len);
secure_vector< uint8_t > ctx(salt + iv_len, salt + salt_len);
store_be(length, be_len);
m_prf->set_key(secret, secret_len);
while(p < key + key_len)
{
const std::size_t to_copy = std::min< std::size_t >(key + key_len - p, prf_len);
uint8_t be_cnt[4] = { 0 };
store_be(counter, be_cnt);
m_prf->update(prev);
m_prf->update(be_cnt,4);
m_prf->update(label,label_len);
m_prf->update(delim);
m_prf->update(ctx);
m_prf->update(be_len,4);
m_prf->final(prev);
copy_mem(p, prev.data(), to_copy);
p += to_copy;
++counter;
BOTAN_ASSERT(counter != 0, "No overflow");
}
return key_len;
}
size_t SP800_108_Pipeline::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
{
const uint32_t length = static_cast<uint32_t>(key_len * 8);
const std::size_t prf_len = m_prf->output_length();
const uint8_t delim = 0;
const uint64_t blocks_required = (key_len + prf_len - 1) / prf_len;
if(blocks_required > 0xFFFFFFFF)
throw Invalid_Argument("SP800_108_Feedback output size too large");
uint8_t *p = key;
uint32_t counter = 1;
uint8_t be_len[4] = { 0 };
secure_vector<uint8_t> ai, ki;
store_be(length, be_len);
m_prf->set_key(secret,secret_len);
// A(0)
std::copy(label,label + label_len,std::back_inserter(ai));
ai.emplace_back(delim);
std::copy(salt,salt + salt_len,std::back_inserter(ai));
std::copy(be_len,be_len + 4,std::back_inserter(ai));
while(p < key + key_len)
{
// A(i)
m_prf->update(ai);
m_prf->final(ai);
// K(i)
const std::size_t to_copy = std::min< std::size_t >(key + key_len - p, prf_len);
uint8_t be_cnt[4] = { 0 };
store_be(counter, be_cnt);
m_prf->update(ai);
m_prf->update(be_cnt,4);
m_prf->update(label, label_len);
m_prf->update(delim);
m_prf->update(salt, salt_len);
m_prf->update(be_len,4);
m_prf->final(ki);
copy_mem(p, ki.data(), to_copy);
p += to_copy;
++counter;
BOTAN_ASSERT(counter != 0, "No overflow");
}
return key_len;
}
}
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