-/* --- NaCl `secretbox' --- */
-
-typedef struct naclbox_encctx {
- bulk b;
- const gccipher *cc;
- gcipher *c;
-} naclbox_encctx;
-
-static bulk *naclbox_init(key *k, const char *calg, const char *halg)
-{
- naclbox_encctx *ctx = CREATE(naclbox_encctx);
- dstr t = DSTR_INIT;
- const char *q;
-
- key_fulltag(k, &t);
-
- if ((q = key_getattr(0, k, "cipher")) != 0) calg = q;
- if (!calg || strcmp(calg, "salsa20") == 0) ctx->cc = &salsa20;
- else if (strcmp(calg, "salsa20/12") == 0) ctx->cc = &salsa2012;
- else if (strcmp(calg, "salsa20/8") == 0) ctx->cc = &salsa208;
- else if (strcmp(calg, "chacha20") == 0) ctx->cc = &chacha20;
- else if (strcmp(calg, "chacha12") == 0) ctx->cc = &chacha12;
- else if (strcmp(calg, "chacha8") == 0) ctx->cc = &chacha8;
- else {
- die(EXIT_FAILURE,
- "unknown or inappropriate encryption scheme `%s' in key `%s'",
- calg, t.buf);
- }
-
- dstr_destroy(&t);
- return (&ctx->b);
-}
-
-static int naclbox_setup(bulk *b, gcipher *cx)
-{
- naclbox_encctx *ctx = (naclbox_encctx *)b;
- octet k[SALSA20_KEYSZ];
-
- GC_ENCRYPT(cx, 0, k, sizeof(k));
- ctx->c = GC_INIT(ctx->cc, k, sizeof(k));
- return (0);
-}
-
-static size_t naclbox_overhead(bulk *b) { return (POLY1305_TAGSZ); }
-
-static void naclbox_destroy(bulk *b)
-{
- naclbox_encctx *ctx = (naclbox_encctx *)b;
-
- GC_DESTROY(ctx->c);
- DESTROY(ctx);
-}
-
-static const char *naclbox_encdoit(bulk *b, uint32 seq, buf *bb,
- const void *p, size_t sz)
-{
- naclbox_encctx *ctx = (naclbox_encctx *)b;
- octet t[32];
- poly1305_key ak;
- poly1305_ctx a;
- octet *tag, *ct;
-
- STORE32(t, seq); STORE32(t + 4, 0); GC_SETIV(ctx->c, t);
- GC_ENCRYPT(ctx->c, 0, t, POLY1305_KEYSZ + POLY1305_MASKSZ);
- poly1305_keyinit(&ak, t, POLY1305_KEYSZ);
- poly1305_macinit(&a, &ak, t + POLY1305_KEYSZ);
-
- tag = buf_get(bb, POLY1305_TAGSZ); assert(tag);
- ct = buf_get(bb, sz); assert(ct);
- GC_ENCRYPT(ctx->c, p, ct, sz);
- poly1305_hash(&a, ct, sz);
- poly1305_done(&a, tag);
- return (0);
-}
-
-static const char *naclbox_decdoit(bulk *b, uint32 seq, buf *bb,
- const void *p, size_t sz)
-{
- naclbox_encctx *ctx = (naclbox_encctx *)b;
- buf bin;
- octet t[32];
- poly1305_key ak;
- poly1305_ctx a;
- octet *tag, *ct, *pt;
-
- STORE32(t, seq); STORE32(t + 4, 0); GC_SETIV(ctx->c, t);
- GC_ENCRYPT(ctx->c, 0, t, POLY1305_KEYSZ + POLY1305_MASKSZ);
- poly1305_keyinit(&ak, t, POLY1305_KEYSZ);
- poly1305_macinit(&a, &ak, t + POLY1305_KEYSZ);
-
- buf_init(&bin, (/*unconst*/ void *)p, sz);
- if ((tag = buf_get(&bin, POLY1305_TAGSZ)) == 0) return ("no tag");
- ct = BCUR(&bin); sz = BLEFT(&bin);
- poly1305_hash(&a, ct, sz);
- poly1305_done(&a, t);
- if (!ct_memeq(t, tag, POLY1305_TAGSZ)) return ("authentication failure");
- pt = buf_get(bb, sz); assert(pt);
- GC_DECRYPT(ctx->c, ct, pt, sz);
- return (0);
-}
-
-static const bulkops naclbox_encops = {
- naclbox_init, naclbox_setup, naclbox_overhead,
- naclbox_encdoit, naclbox_destroy
-}, naclbox_decops = {
- naclbox_init, naclbox_setup, naclbox_overhead,
- naclbox_decdoit, naclbox_destroy
-};
-