progs/cc-kem.c: Add `naclbox' crypto transform.

[catacomb] / progs / cc-kem.c

diff --git a/progs/cc-kem.c b/progs/cc-kem.c
index 6c4d7f306ea52fd8e07e32abd50ede8ec7877de7..4a2cf1924c6286eac9b7d8ba6a925254f89ff8a8 100644 (file)
--- a/progs/cc-kem.c
+++ b/progs/cc-kem.c
@@ -46,11 +46,123 @@
 
 #include "rmd160.h"
 #include "blowfish-cbc.h"
+#include "poly1305.h"
+#include "salsa20.h"
+#include "chacha.h"
 
 #include "cc.h"
 
 /*----- Bulk crypto -------------------------------------------------------*/
 
+/* --- 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
+};
+
 /* --- Generic composition --- */
 
 typedef struct gencomp_encctx {
@@ -185,6 +297,7 @@ static const bulkops gencomp_encops = {
 
 const struct bulktab bulktab[] = {
   { "gencomp", &gencomp_encops,        &gencomp_decops },
+  { "naclbox", &naclbox_encops,        &naclbox_decops },
   { 0,         0,                      0 }
 };