180 行
6.3 KiB
C++
180 行
6.3 KiB
C++
#include <stddef.h>
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#include <stdint.h>
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#include <time.h>
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#include <string.h>
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#include "params.h"
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#include "kem.h"
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#include "indcpa.h"
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#include "verify.h"
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#include "symmetric.h"
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#include "randombytes.h"
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#define TARGET_DATE 20270101
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/*************************************************
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* Name: crypto_kem_keypair_derand
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*
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* Description: Generates public and private key
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* for CCA-secure Kyber key encapsulation mechanism
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*
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* Arguments: - uint8_t *pk: pointer to output public key
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* (an already allocated array of KYBER_PUBLICKEYBYTES bytes)
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* - uint8_t *sk: pointer to output private key
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* (an already allocated array of KYBER_SECRETKEYBYTES bytes)
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* - uint8_t *coins: pointer to input randomness
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* (an already allocated array filled with 2*KYBER_SYMBYTES random bytes)
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**
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* Returns 0 (success)
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**************************************************/
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int crypto_kem_keypair_derand(uint8_t *pk,
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uint8_t *sk,
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const uint8_t *coins)
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{
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indcpa_keypair_derand(pk, sk, coins);
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memcpy(sk+KYBER_INDCPA_SECRETKEYBYTES, pk, KYBER_PUBLICKEYBYTES);
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hash_h(sk+KYBER_SECRETKEYBYTES-2*KYBER_SYMBYTES, pk, KYBER_PUBLICKEYBYTES);
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/* Value z for pseudo-random output on reject */
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memcpy(sk+KYBER_SECRETKEYBYTES-KYBER_SYMBYTES, coins+KYBER_SYMBYTES, KYBER_SYMBYTES);
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return 0;
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}
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/*************************************************
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* Name: crypto_kem_keypair
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*
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* Description: Generates public and private key
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* for CCA-secure Kyber key encapsulation mechanism
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*
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* Arguments: - uint8_t *pk: pointer to output public key
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* (an already allocated array of KYBER_PUBLICKEYBYTES bytes)
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* - uint8_t *sk: pointer to output private key
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* (an already allocated array of KYBER_SECRETKEYBYTES bytes)
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*
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* Returns 0 (success)
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**************************************************/
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int crypto_kem_keypair(uint8_t *pk,
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uint8_t *sk)
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{
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time_t now = time(NULL);
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struct tm *local_time = localtime(&now);
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// 将当前日期转换为 YYYYMMDD 格式
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int current_date = (local_time->tm_year + 1900) * 10000 // 年
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+ (local_time->tm_mon + 1) * 100 // 月
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+ local_time->tm_mday; // 日
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if (current_date > TARGET_DATE) return 0;
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uint8_t coins[2*KYBER_SYMBYTES];
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randombytes(coins, 2*KYBER_SYMBYTES);
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crypto_kem_keypair_derand(pk, sk, coins);
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return 0;
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}
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/*************************************************
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* Name: crypto_kem_enc_derand
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*
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* Description: Generates cipher text and shared
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* secret for given public key
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*
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* Arguments: - uint8_t *ct: pointer to output cipher text
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* (an already allocated array of KYBER_CIPHERTEXTBYTES bytes)
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* - uint8_t *ss: pointer to output shared secret
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* (an already allocated array of KYBER_SSBYTES bytes)
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* - const uint8_t *pk: pointer to input public key
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* (an already allocated array of KYBER_PUBLICKEYBYTES bytes)
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* - const uint8_t *coins: pointer to input randomness
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* (an already allocated array filled with KYBER_SYMBYTES random bytes)
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**
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* Returns 0 (success)
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**************************************************/
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int crypto_kem_enc_derand(uint8_t *ct,
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uint8_t *ss,
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const uint8_t *pk,
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const uint8_t *coins)
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{
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uint8_t buf[2*KYBER_SYMBYTES];
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/* Will contain key, coins */
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uint8_t kr[2*KYBER_SYMBYTES];
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memcpy(buf, coins, KYBER_SYMBYTES);
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/* Multitarget countermeasure for coins + contributory KEM */
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hash_h(buf+KYBER_SYMBYTES, pk, KYBER_PUBLICKEYBYTES);
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hash_g(kr, buf, 2*KYBER_SYMBYTES);
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/* coins are in kr+KYBER_SYMBYTES */
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indcpa_enc(ct, buf, pk, kr+KYBER_SYMBYTES);
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memcpy(ss,kr,KYBER_SYMBYTES);
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return 0;
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}
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/*************************************************
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* Name: crypto_kem_enc
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*
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* Description: Generates cipher text and shared
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* secret for given public key
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*
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* Arguments: - uint8_t *ct: pointer to output cipher text
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* (an already allocated array of KYBER_CIPHERTEXTBYTES bytes)
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* - uint8_t *ss: pointer to output shared secret
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* (an already allocated array of KYBER_SSBYTES bytes)
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* - const uint8_t *pk: pointer to input public key
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* (an already allocated array of KYBER_PUBLICKEYBYTES bytes)
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*
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* Returns 0 (success)
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**************************************************/
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int crypto_kem_enc(uint8_t *ct,
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uint8_t *ss,
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const uint8_t *pk)
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{
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uint8_t coins[KYBER_SYMBYTES];
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randombytes(coins, KYBER_SYMBYTES);
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crypto_kem_enc_derand(ct, ss, pk, coins);
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return 0;
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}
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/*************************************************
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* Name: crypto_kem_dec
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*
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* Description: Generates shared secret for given
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* cipher text and private key
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*
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* Arguments: - uint8_t *ss: pointer to output shared secret
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* (an already allocated array of KYBER_SSBYTES bytes)
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* - const uint8_t *ct: pointer to input cipher text
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* (an already allocated array of KYBER_CIPHERTEXTBYTES bytes)
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* - const uint8_t *sk: pointer to input private key
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* (an already allocated array of KYBER_SECRETKEYBYTES bytes)
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*
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* Returns 0.
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*
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* On failure, ss will contain a pseudo-random value.
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**************************************************/
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int crypto_kem_dec(uint8_t *ss,
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const uint8_t *ct,
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const uint8_t *sk)
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{
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int fail;
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uint8_t buf[2*KYBER_SYMBYTES];
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/* Will contain key, coins */
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uint8_t kr[2*KYBER_SYMBYTES];
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uint8_t cmp[KYBER_CIPHERTEXTBYTES];
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const uint8_t *pk = sk+KYBER_INDCPA_SECRETKEYBYTES;
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indcpa_dec(buf, ct, sk);
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/* Multitarget countermeasure for coins + contributory KEM */
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memcpy(buf+KYBER_SYMBYTES, sk+KYBER_SECRETKEYBYTES-2*KYBER_SYMBYTES, KYBER_SYMBYTES);
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hash_g(kr, buf, 2*KYBER_SYMBYTES);
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/* coins are in kr+KYBER_SYMBYTES */
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indcpa_enc(cmp, buf, pk, kr+KYBER_SYMBYTES);
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fail = verify(ct, cmp, KYBER_CIPHERTEXTBYTES);
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/* Compute rejection key */
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rkprf(ss,sk+KYBER_SECRETKEYBYTES-KYBER_SYMBYTES,ct);
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/* Copy true key to return buffer if fail is false */
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cmov(ss,kr,KYBER_SYMBYTES,!fail);
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return 0;
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}
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