1
0
mirror of https://codeberg.org/Freeyourgadget/Gadgetbridge synced 2024-11-16 06:59:29 +01:00
Gadgetbridge/app/src/main/c/ecdh.h
2021-08-26 10:59:53 +02:00

113 lines
3.0 KiB
C

/*
Crypto using elliptic curves defined over the finite binary field GF(2^m) where m is prime.
The curves used are the anomalous binary curves (ABC-curves) or also called Koblitz curves.
This class of curves was chosen because it yields efficient implementation of operations.
Curves available - their different NIST/SECG names and eqivalent symmetric security level:
NIST SEC Group strength
------------------------------------
K-163 sect163k1 80 bit
B-163 sect163r2 80 bit
K-233 sect233k1 112 bit
B-233 sect233r1 112 bit
K-283 sect283k1 128 bit
B-283 sect283r1 128 bit
K-409 sect409k1 192 bit
B-409 sect409r1 192 bit
K-571 sect571k1 256 bit
B-571 sect571r1 256 bit
Curve parameters from:
http://www.secg.org/sec2-v2.pdf
http://csrc.nist.gov/publications/fips/fips186-3/fips_186-3.pdf
Reference:
https://www.ietf.org/rfc/rfc4492.txt
*/
#ifndef _ECDH_H__
#define _ECDH_H__
/* for size-annotated integer types: uint8_t, uint32_t etc. */
#include <stdint.h>
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
#define NIST_B163 1
#define NIST_K163 2
#define NIST_B233 3
#define NIST_K233 4
#define NIST_B283 5
#define NIST_K283 6
#define NIST_B409 7
#define NIST_K409 8
#define NIST_B571 9
#define NIST_K571 10
/* What is the default curve to use? */
#ifndef ECC_CURVE
#define ECC_CURVE NIST_B163
#endif
#if defined(ECC_CURVE) && (ECC_CURVE != 0)
#if (ECC_CURVE == NIST_K163) || (ECC_CURVE == NIST_B163)
#define CURVE_DEGREE 163
#define ECC_PRV_KEY_SIZE 24
#elif (ECC_CURVE == NIST_K233) || (ECC_CURVE == NIST_B233)
#define CURVE_DEGREE 233
#define ECC_PRV_KEY_SIZE 32
#elif (ECC_CURVE == NIST_K283) || (ECC_CURVE == NIST_B283)
#define CURVE_DEGREE 283
#define ECC_PRV_KEY_SIZE 36
#elif (ECC_CURVE == NIST_K409) || (ECC_CURVE == NIST_B409)
#define CURVE_DEGREE 409
#define ECC_PRV_KEY_SIZE 52
#elif (ECC_CURVE == NIST_K571) || (ECC_CURVE == NIST_B571)
#define CURVE_DEGREE 571
#define ECC_PRV_KEY_SIZE 72
#endif
#else
#error Must define a curve to use
#endif
#define ECC_PUB_KEY_SIZE (2 * ECC_PRV_KEY_SIZE)
/******************************************************************************/
/* NOTE: assumes private is filled with random data before calling */
int ecdh_generate_keys(uint8_t* public_key, uint8_t* private_key);
/* input: own private key + other party's public key, output: shared secret */
int ecdh_shared_secret(const uint8_t* private_key, const uint8_t* others_pub, uint8_t* output);
/* Broken :( .... */
int ecdsa_sign(const uint8_t* private_key, uint8_t* hash, uint8_t* random_k, uint8_t* signature);
int ecdsa_verify(const uint8_t* public_key, uint8_t* hash, const uint8_t* signature);
/******************************************************************************/
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* #ifndef _ECDH_H__ */