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      1 
      2 #include <limits.h>
      3 #include <stdint.h>
      4 #include <stdlib.h>
      5 #include <string.h>
      6 
      7 #include "core.h"
      8 #include "crypto_box_curve25519xchacha20poly1305.h"
      9 #include "crypto_core_hchacha20.h"
     10 #include "crypto_hash_sha512.h"
     11 #include "crypto_scalarmult_curve25519.h"
     12 #include "crypto_secretbox_xchacha20poly1305.h"
     13 #include "private/common.h"
     14 #include "randombytes.h"
     15 #include "utils.h"
     16 
     17 int
     18 crypto_box_curve25519xchacha20poly1305_seed_keypair(unsigned char *pk,
     19                                                     unsigned char *sk,
     20                                                     const unsigned char *seed)
     21 {
     22     unsigned char hash[64];
     23 
     24     crypto_hash_sha512(hash, seed, 32);
     25     memcpy(sk, hash, 32);
     26     sodium_memzero(hash, sizeof hash);
     27 
     28     return crypto_scalarmult_curve25519_base(pk, sk);
     29 }
     30 
     31 int
     32 crypto_box_curve25519xchacha20poly1305_keypair(unsigned char *pk,
     33                                                unsigned char *sk)
     34 {
     35     randombytes_buf(sk, 32);
     36 
     37     return crypto_scalarmult_curve25519_base(pk, sk);
     38 }
     39 
     40 int
     41 crypto_box_curve25519xchacha20poly1305_beforenm(unsigned char *k,
     42                                                 const unsigned char *pk,
     43                                                 const unsigned char *sk)
     44 {
     45     static const unsigned char zero[16] = { 0 };
     46     unsigned char s[32];
     47 
     48     if (crypto_scalarmult_curve25519(s, sk, pk) != 0) {
     49         return -1;
     50     }
     51     return crypto_core_hchacha20(k, zero, s, NULL);
     52 }
     53 
     54 int
     55 crypto_box_curve25519xchacha20poly1305_detached_afternm(
     56     unsigned char *c, unsigned char *mac, const unsigned char *m,
     57     unsigned long long mlen, const unsigned char *n, const unsigned char *k)
     58 {
     59     return crypto_secretbox_xchacha20poly1305_detached(c, mac, m, mlen, n, k);
     60 }
     61 
     62 int
     63 crypto_box_curve25519xchacha20poly1305_detached(
     64     unsigned char *c, unsigned char *mac, const unsigned char *m,
     65     unsigned long long mlen, const unsigned char *n, const unsigned char *pk,
     66     const unsigned char *sk)
     67 {
     68     unsigned char k[crypto_box_curve25519xchacha20poly1305_BEFORENMBYTES];
     69     int           ret;
     70 
     71     COMPILER_ASSERT(crypto_box_curve25519xchacha20poly1305_BEFORENMBYTES >=
     72                     crypto_secretbox_xchacha20poly1305_KEYBYTES);
     73     if (crypto_box_curve25519xchacha20poly1305_beforenm(k, pk, sk) != 0) {
     74         return -1;
     75     }
     76     ret = crypto_box_curve25519xchacha20poly1305_detached_afternm(c, mac, m,
     77                                                                   mlen, n, k);
     78     sodium_memzero(k, sizeof k);
     79 
     80     return ret;
     81 }
     82 
     83 int
     84 crypto_box_curve25519xchacha20poly1305_easy_afternm(unsigned char *c,
     85                                                     const unsigned char *m,
     86                                                     unsigned long long mlen,
     87                                                     const unsigned char *n,
     88                                                     const unsigned char *k)
     89 {
     90     if (mlen > crypto_box_curve25519xchacha20poly1305_MESSAGEBYTES_MAX) {
     91         sodium_misuse();
     92     }
     93     return crypto_box_curve25519xchacha20poly1305_detached_afternm(
     94         c + crypto_box_curve25519xchacha20poly1305_MACBYTES, c, m, mlen, n, k);
     95 }
     96 
     97 int
     98 crypto_box_curve25519xchacha20poly1305_easy(
     99     unsigned char *c, const unsigned char *m, unsigned long long mlen,
    100     const unsigned char *n, const unsigned char *pk, const unsigned char *sk)
    101 {
    102     if (mlen > crypto_box_curve25519xchacha20poly1305_MESSAGEBYTES_MAX) {
    103         sodium_misuse();
    104     }
    105     return crypto_box_curve25519xchacha20poly1305_detached(
    106         c + crypto_box_curve25519xchacha20poly1305_MACBYTES, c, m, mlen, n, pk,
    107         sk);
    108 }
    109 
    110 int
    111 crypto_box_curve25519xchacha20poly1305_open_detached_afternm(
    112     unsigned char *m, const unsigned char *c, const unsigned char *mac,
    113     unsigned long long clen, const unsigned char *n, const unsigned char *k)
    114 {
    115     return crypto_secretbox_xchacha20poly1305_open_detached(m, c, mac, clen, n,
    116                                                             k);
    117 }
    118 
    119 int
    120 crypto_box_curve25519xchacha20poly1305_open_detached(
    121     unsigned char *m, const unsigned char *c, const unsigned char *mac,
    122     unsigned long long clen, const unsigned char *n, const unsigned char *pk,
    123     const unsigned char *sk)
    124 {
    125     unsigned char k[crypto_box_curve25519xchacha20poly1305_BEFORENMBYTES];
    126     int           ret;
    127 
    128     if (crypto_box_curve25519xchacha20poly1305_beforenm(k, pk, sk) != 0) {
    129         return -1;
    130     }
    131     ret = crypto_box_curve25519xchacha20poly1305_open_detached_afternm(
    132         m, c, mac, clen, n, k);
    133     sodium_memzero(k, sizeof k);
    134 
    135     return ret;
    136 }
    137 
    138 int
    139 crypto_box_curve25519xchacha20poly1305_open_easy_afternm(
    140     unsigned char *m, const unsigned char *c, unsigned long long clen,
    141     const unsigned char *n, const unsigned char *k)
    142 {
    143     if (clen < crypto_box_curve25519xchacha20poly1305_MACBYTES) {
    144         return -1;
    145     }
    146     return crypto_box_curve25519xchacha20poly1305_open_detached_afternm(
    147         m, c + crypto_box_curve25519xchacha20poly1305_MACBYTES, c,
    148         clen - crypto_box_curve25519xchacha20poly1305_MACBYTES, n, k);
    149 }
    150 
    151 int
    152 crypto_box_curve25519xchacha20poly1305_open_easy(
    153     unsigned char *m, const unsigned char *c, unsigned long long clen,
    154     const unsigned char *n, const unsigned char *pk, const unsigned char *sk)
    155 {
    156     if (clen < crypto_box_curve25519xchacha20poly1305_MACBYTES) {
    157         return -1;
    158     }
    159     return crypto_box_curve25519xchacha20poly1305_open_detached(
    160         m, c + crypto_box_curve25519xchacha20poly1305_MACBYTES, c,
    161         clen - crypto_box_curve25519xchacha20poly1305_MACBYTES, n, pk, sk);
    162 }
    163 
    164 size_t
    165 crypto_box_curve25519xchacha20poly1305_seedbytes(void)
    166 {
    167     return crypto_box_curve25519xchacha20poly1305_SEEDBYTES;
    168 }
    169 
    170 size_t
    171 crypto_box_curve25519xchacha20poly1305_publickeybytes(void)
    172 {
    173     return crypto_box_curve25519xchacha20poly1305_PUBLICKEYBYTES;
    174 }
    175 
    176 size_t
    177 crypto_box_curve25519xchacha20poly1305_secretkeybytes(void)
    178 {
    179     return crypto_box_curve25519xchacha20poly1305_SECRETKEYBYTES;
    180 }
    181 
    182 size_t
    183 crypto_box_curve25519xchacha20poly1305_beforenmbytes(void)
    184 {
    185     return crypto_box_curve25519xchacha20poly1305_BEFORENMBYTES;
    186 }
    187 
    188 size_t
    189 crypto_box_curve25519xchacha20poly1305_noncebytes(void)
    190 {
    191     return crypto_box_curve25519xchacha20poly1305_NONCEBYTES;
    192 }
    193 
    194 size_t
    195 crypto_box_curve25519xchacha20poly1305_macbytes(void)
    196 {
    197     return crypto_box_curve25519xchacha20poly1305_MACBYTES;
    198 }
    199 
    200 size_t
    201 crypto_box_curve25519xchacha20poly1305_messagebytes_max(void)
    202 {
    203     return crypto_box_curve25519xchacha20poly1305_MESSAGEBYTES_MAX;
    204 }
    205