/*
* Copyright (c) 2020 Belledonne Communications SARL.
*
* This file is part of bctoolbox.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*/
#ifndef BCTBX_CRYPTO_HH
#define BCTBX_CRYPTO_HH
#include
#include
namespace bctoolbox {
/**
* @brief Random number generator interface
*
* This wrapper provides an interface to a RNG.
* Two ways to get some random numbers:
* - calling the static class functions(cRandomize) : do not use this to feed cryptographic functions
* - instanciate a RNG object and call the randomize method : use this one for cryptographic quality random
*
* Any call (including creation), may throw an exception if some error are detected on the random source
*/
class RNG {
public:
/**
* fill a buffer with random numbers
* @param[in,out] buffer The buffer to be filled with random (callers responsability to allocate memory)
* @param[in] size size in bytes of the random generated, buffer must be at least of this size
**/
void randomize(uint8_t *buffer, const size_t size);
/**
* return a random vector of given size
* @param[in] size size in bytes of the random generated
**/
std::vector randomize(const size_t size);
/**
* generates a 32 bits random unsigned number
**/
uint32_t randomize();
/**
* fill a buffer with random numbers
* @param[in,out] buffer The buffer to be filled with random (callers responsability to allocate memory)
* @param[in] size size in bytes of the random generated, buffer must be at least of this size
*
* @note This function uses a shared RNG context, do not use it to generate sensitive material
**/
static void cRandomize(uint8_t *buffer, size_t size);
/**
* generates a 32 bits random unsigned number
*
* @note This function uses a shared RNG context, do not use it to generate sensitive material
**/
static uint32_t cRandomize();
RNG();
~RNG();
private:
struct Impl;
std::unique_ptr pImpl;
static std::unique_ptr pImplClass;
}; //class RNG
/*****************************************************************************/
/*** Hash related function ***/
/*****************************************************************************/
/**
* @brief SHA256 buffer size definition
*/
struct SHA256 {
/// maximum output size for SHA256 is 32 bytes
static constexpr size_t ssize() {return 32;}
};
/**
* @brief SHA384 buffer size definition
*/
struct SHA384 {
/// maximum output size for SHA384 is 48 bytes
static constexpr size_t ssize() {return 48;}
};
/**
* @brief SHA512 buffer size definition
*/
struct SHA512 {
/// maximum output size for SHA512 is 64 bytes
static constexpr size_t ssize() {return 64;}
};
/**
* @brief templated HMAC
*
* @tparam hashAlgo the hash algorithm used: SHA256, SHA384, SHA512
*
* @param[in] key HMAC key
* @param[in] input HMAC input
*
* @return an array of size matching the selected hash algorithm output size
*
*/
template
std::vector HMAC(const std::vector &key, const std::vector &input);
/* declare template specialisations */
template <> std::vector HMAC(const std::vector &key, const std::vector &input);
template <> std::vector HMAC(const std::vector &key, const std::vector &input);
template <> std::vector HMAC(const std::vector &key, const std::vector &input);
/**
* @brief HKDF as described in RFC5869
* @par Compute:
* @code{.unparsed}
* PRK = HMAC-Hash(salt, IKM)
*
* N = ceil(L/HashLen)
* T = T(1) | T(2) | T(3) | ... | T(N)
* OKM = first L octets of T
*
* where:
* T(0) = empty string (zero length)
* T(1) = HMAC-Hash(PRK, T(0) | info | 0x01)
* T(2) = HMAC-Hash(PRK, T(1) | info | 0x02)
* T(3) = HMAC-Hash(PRK, T(2) | info | 0x03)
* ...
* @endcode
*
* @tparam hashAlgo the hash algorithm to use
* @tparam infoType the info parameter type : can be passed as a string or a std::vector
*
* @param[in] salt salt
* @param[in] ikm input key material
* @param[in] info a info string or buffer
* @param[in] okmSize requested amount of data. (L in the RFC doc)
*
* @return the output key material
*
*/
template
std::vector HKDF(const std::vector &salt, const std::vector &ikm, const std::vector &info, size_t okmSize);
template
std::vector HKDF(const std::vector &salt, const std::vector &ikm, const std::string &info, size_t okmSize);
/* declare template specialisations */
template <> std::vector HKDF(const std::vector &salt, const std::vector &ikm, const std::vector &info, size_t outputSize);
template <> std::vector HKDF(const std::vector &salt, const std::vector &ikm, const std::string &info, size_t outputSize);
template <> std::vector HKDF(const std::vector &salt, const std::vector &ikm, const std::vector &info, size_t outputSize);
template <> std::vector HKDF(const std::vector &salt, const std::vector &ikm, const std::string &info, size_t outputSize);
/************************ AEAD interface *************************************/
// AEAD function defines
/**
* @brief AES256GCM buffers size definition
*/
struct AES256GCM128 {
/// key size is 32 bytes
static constexpr size_t keySize(void) {return 32;};
/// tag size is 16 bytes
static constexpr size_t tagSize(void) {return 16;};
};
/**
* @brief Encrypt and tag using scheme given as template parameter
*
* @param[in] key Encryption key
* @param[in] IV Initialisation vector
* @param[in] plain Plain text
* @param[in] AD Additional data used in tag computation
* @param[out] tag Generated authentication tag
* @return the cipher text
*/
template
std::vector AEADEncrypt(const std::vector &key, const std::vector IV, const std::vector &plain, const std::vector &AD,
std::vector &tag);
/**
* @brief Authenticate and Decrypt using scheme given as template parameter
*
* @param[in] key Encryption key
* @param[in] IV Initialisation vector
* @param[in] cipher Cipher text
* @param[in] AD Additional data used in tag computation
* @param[in] tag Authentication tag
* @param[out] plain A vector to store the plain text
*
* @return true if authentication tag match and decryption was successful
*/
template
bool AEADDecrypt(const std::vector &key, const std::vector &IV, const std::vector &cipher, const std::vector &AD,
const std::vector &tag, std::vector &plain);
/* declare AEAD template specialisations : AES256-GCM with 128 bits auth tag*/
template <> std::vector AEADEncrypt(const std::vector &key, const std::vector IV, const std::vector &plain, const std::vector &AD,
std::vector &tag);
template <> bool AEADDecrypt(const std::vector &key, const std::vector &IV, const std::vector &cipher, const std::vector &AD,
const std::vector &tag, std::vector &plain);
} // namespace bctoolbox
#endif // BCTBX_CRYPTO_HH