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      1 
      2 #include <string.h>
      3 
      4 #include "crypto_box.h"
      5 #include "crypto_generichash.h"
      6 #include "private/common.h"
      7 #include "utils.h"
      8 
      9 static int
     10 _crypto_box_seal_nonce(unsigned char *nonce,
     11                        const unsigned char *pk1, const unsigned char *pk2)
     12 {
     13     crypto_generichash_state st;
     14 
     15     crypto_generichash_init(&st, NULL, 0U, crypto_box_NONCEBYTES);
     16     crypto_generichash_update(&st, pk1, crypto_box_PUBLICKEYBYTES);
     17     crypto_generichash_update(&st, pk2, crypto_box_PUBLICKEYBYTES);
     18     crypto_generichash_final(&st, nonce, crypto_box_NONCEBYTES);
     19 
     20     return 0;
     21 }
     22 
     23 int
     24 crypto_box_seal(unsigned char *c, const unsigned char *m,
     25                 unsigned long long mlen, const unsigned char *pk)
     26 {
     27     unsigned char nonce[crypto_box_NONCEBYTES];
     28     unsigned char epk[crypto_box_PUBLICKEYBYTES];
     29     unsigned char esk[crypto_box_SECRETKEYBYTES];
     30     int           ret;
     31 
     32     if (crypto_box_keypair(epk, esk) != 0) {
     33         return -1; /* LCOV_EXCL_LINE */
     34     }
     35     memcpy(c, epk, crypto_box_PUBLICKEYBYTES);
     36     _crypto_box_seal_nonce(nonce, epk, pk);
     37     ret = crypto_box_easy(c + crypto_box_PUBLICKEYBYTES, m, mlen,
     38                           nonce, pk, esk);
     39     sodium_memzero(esk, sizeof esk);
     40     sodium_memzero(epk, sizeof epk);
     41     sodium_memzero(nonce, sizeof nonce);
     42 
     43     return ret;
     44 }
     45 
     46 int
     47 crypto_box_seal_open(unsigned char *m, const unsigned char *c,
     48                      unsigned long long clen,
     49                      const unsigned char *pk, const unsigned char *sk)
     50 {
     51     unsigned char nonce[crypto_box_NONCEBYTES];
     52 
     53     if (clen < crypto_box_SEALBYTES) {
     54         return -1;
     55     }
     56     _crypto_box_seal_nonce(nonce, c, pk);
     57 
     58     COMPILER_ASSERT(crypto_box_PUBLICKEYBYTES < crypto_box_SEALBYTES);
     59     return crypto_box_open_easy(m, c + crypto_box_PUBLICKEYBYTES,
     60                                 clen - crypto_box_PUBLICKEYBYTES,
     61                                 nonce, c, sk);
     62 }
     63 
     64 size_t
     65 crypto_box_sealbytes(void)
     66 {
     67     return crypto_box_SEALBYTES;
     68 }
     69