esp-ena/components/ena/include/ena-crypto.h

126 lines
4.6 KiB
C

// Copyright 2020 Lukas Haubaum
//
// Licensed under the GNU Affero General Public License, Version 3;
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// https://www.gnu.org/licenses/agpl-3.0.html
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
/**
* @file
*
* @brief covers cryptography part (key creation, encryption etc.)
*
*/
#ifndef _ena_CRYPTO_H_
#define _ena_CRYPTO_H_
#define ENA_TIME_WINDOW (600) // time window every 10 minutes
#define ENA_KEY_LENGTH (16) // key length
#define ENA_AEM_METADATA_LENGTH (4) // size of metadata
#define ENA_TEK_ROLLING_PERIOD (CONFIG_ENA_TEK_ROLLING_PERIOD) // TEKRollingPeriod
#include <stdio.h>
/**
* @brief initialize cryptography
*
* This initialize the cryptography by setting up entropy.
*/
void ena_crypto_init(void);
/**
* @brief calculate ENIntervalNumber (ENIN) for given UNIX timestamp
*
* Source documents (Section: ENIntervalNumber)
*
* https://blog.google/documents/69/Exposure_Notification_-_Cryptography_Specification_v1.2.1.pdf
*
* https://covid19-static.cdn-apple.com/applications/covid19/current/static/detection-tracing/pdf/ExposureNotification-CryptographySpecificationv1.2.pdf
*
*
* @param[in] unix_timestamp UNIX Timestamp to calculate ENIN for
*
* @return
* ENIN for given timestamp
*/
uint32_t ena_crypto_enin(uint32_t unix_timestamp);
/**
* @brief calculate a new random Temporary Exposure Key (TEK)
*
* Source documents (Section: Temporary Exposure Key)
*
* https://blog.google/documents/69/Exposure_Notification_-_Cryptography_Specification_v1.2.1.pdf
*
* https://covid19-static.cdn-apple.com/applications/covid19/current/static/detection-tracing/pdf/ExposureNotification-CryptographySpecificationv1.2.pdf
*
* @param[out] tek pointer to the new TEK
*/
void ena_crypto_tek(uint8_t *tek);
/**
* @brief calculate a new Rolling Proximity Identifier Key (RPIK) with given TEK
*
* Source documents (Section: Rolling Proximity Identifier Key)
*
* https://blog.google/documents/69/Exposure_Notification_-_Cryptography_Specification_v1.2.1.pdf
*
* https://covid19-static.cdn-apple.com/applications/covid19/current/static/detection-tracing/pdf/ExposureNotification-CryptographySpecificationv1.2.pdf
*
* @param[out] rpik pointer to the new RPIK
* @param[in] tek TEK for calculating RPIK
*/
void ena_crypto_rpik(uint8_t *rpik, uint8_t *tek);
/**
* @brief calculate a new Rolling Proximity Identifier with given RPIK and ENIN
*
* Source documents (Section: Rolling Proximity Identifier)
*
* https://blog.google/documents/69/Exposure_Notification_-_Cryptography_Specification_v1.2.1.pdf
*
* https://covid19-static.cdn-apple.com/applications/covid19/current/static/detection-tracing/pdf/ExposureNotification-CryptographySpecificationv1.2.pdf
*
* @param[out] rpi pointer to the new RPI
* @param[in] rpik RPIK for encrypting RPI
* @param[in] enin ENIN to encrypt in RPI
*/
void ena_crypto_rpi(uint8_t *rpi, uint8_t *rpik, uint32_t enin);
/**
* @brief calculate a new Associated Encrypted Metadata Key (AEMK) with given TEK
*
* Source documents (Section: Associated Encrypted Metadata Key)
*
* https://blog.google/documents/69/Exposure_Notification_-_Cryptography_Specification_v1.2.1.pdf
*
* https://covid19-static.cdn-apple.com/applications/covid19/current/static/detection-tracing/pdf/ExposureNotification-CryptographySpecificationv1.2.pdf
*
* @param[out] aemk pointer to the new AEMK
* @param[in] tek TEK for calculating AEMK
*/
void ena_crypto_aemk(uint8_t *aemk, uint8_t *tek);
/**
* @brief create Associated Encrypted Metadata (AEM) with given AEMK along the RPI
*
* Source documents (Section: Associated Encrypted Metadata)
*
* https://blog.google/documents/69/Exposure_Notification_-_Cryptography_Specification_v1.2.1.pdf
*
* https://covid19-static.cdn-apple.com/applications/covid19/current/static/detection-tracing/pdf/ExposureNotification-CryptographySpecificationv1.2.pdf
*
* @param[out] aem pointer to the new AEM
* @param[in] aemk AEMK for encrypting AEM
* @param[in] rpi RPI for encrypting AEM
* @param[in] power_level BLE power level to encrypt in AEM
*/
void ena_crypto_aem(uint8_t *aem, uint8_t *aemk, uint8_t *rpi, uint8_t power_level);
#endif