Add GOST DSA according to GOST R 34.10-2001/-2012

Add GOST Digital Signature Algorithms support according to GOST R
34.10-2001/-2012. English translations of these standards are provided
as RFC 5832 and RFC 7091.

Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>

1 files changed, 111 insertions, 0 deletions

diff --git a/testsuite/gostdsa-verify-test.c b/testsuite/gostdsa-verify-test.c
new file mode 100644
index 00000000..7279f5f4
--- /dev/null
+++ b/testsuite/gostdsa-verify-test.c
@@ -0,0 +1,111 @@
+#include "testutils.h"
+#include "gostdsa.h"
+
+static void
+test_gostdsa (const struct ecc_curve *ecc,
+	    /* Public key */
+	    const char *xs, const char *ys,
+	    /* Hash */
+	    struct tstring *h,
+	    /* Valid signature */
+	    const char *r, const char *s)
+{
+  struct ecc_point pub;
+  struct dsa_signature signature;
+  mpz_t x, y;
+
+  ecc_point_init (&pub, ecc);
+  dsa_signature_init (&signature);
+
+  mpz_init_set_str (x, xs, 16);
+  mpz_init_set_str (y, ys, 16);
+
+  if (!ecc_point_set (&pub, x, y))
+    die ("ecc_point_set failed.\n");
+
+  mpz_set_str (signature.r, r, 16);
+  mpz_set_str (signature.s, s, 16);
+
+  if (!gostdsa_verify (&pub, h->length, h->data, &signature))
+    {
+      fprintf (stderr, "gostdsa_verify failed with valid signature.\n");
+    fail:
+      fprintf (stderr, "bit_size = %u\nx = ", ecc->p.bit_size);
+      mpz_out_str (stderr, 16, x);
+      fprintf (stderr, "\ny = ");
+      mpz_out_str (stderr, 16, y);
+      fprintf (stderr, "\ndigest ");
+      print_hex (h->length, h->data);
+      fprintf (stderr, "r = ");
+      mpz_out_str (stderr, 16, signature.r);
+      fprintf (stderr, "\ns = ");
+      mpz_out_str (stderr, 16, signature.s);
+      fprintf (stderr, "\n");
+      abort();
+    }
+
+  mpz_combit (signature.r, ecc->p.bit_size / 3);
+  if (gostdsa_verify (&pub, h->length, h->data, &signature))
+    {
+      fprintf (stderr, "gostdsa_verify unexpectedly succeeded with invalid signature.\n");
+      goto fail;
+    }
+  mpz_combit (signature.r, ecc->p.bit_size / 3);
+
+  mpz_combit (signature.s, 4*ecc->p.bit_size / 5);
+  if (gostdsa_verify (&pub, h->length, h->data, &signature))
+    {
+      fprintf (stderr, "gostdsa_verify unexpectedly succeeded with invalid signature.\n");
+      goto fail;
+    }
+  mpz_combit (signature.s, 4*ecc->p.bit_size / 5);
+
+  h->data[2*h->length / 3] ^= 0x40;
+  if (gostdsa_verify (&pub, h->length, h->data, &signature))
+    {
+      fprintf (stderr, "gostdsa_verify unexpectedly succeeded with invalid signature.\n");
+      goto fail;
+    }
+  h->data[2*h->length / 3] ^= 0x40;
+  if (!gostdsa_verify (&pub, h->length, h->data, &signature))
+    {
+      fprintf (stderr, "gostdsa_verify failed, internal testsuite error.\n");
+      goto fail;
+    }
+
+  ecc_point_clear (&pub);
+  dsa_signature_clear (&signature);
+  mpz_clear (x);
+  mpz_clear (y);
+}
+
+void
+test_main (void)
+{
+  test_gostdsa (nettle_get_gost_gc256b(),
+	      "971566CEDA436EE7678F7E07E84EBB7217406C0B4747AA8FD2AB1453C3D0DFBA", /* x */
+
+	      "AD58736965949F8E59830F8DE20FC6C0D177F6AB599874F1E2E24FF71F9CE643", /* y */
+
+	      SHEX("1C067E20EA6CB183F22EFB0F3C6FD2A4E6A02821CB7A1B17FACD5E1F7AA76F70"), /* h */
+
+	      "E9323A5E88DD87FB7C724383BFFE7CECD4B9FFA2AC33BEEF73A5A1F743404F6B", /* r */
+
+	      "5E5B9B805B01147A8492C4A162643AC615DC777B9174108F3DC276A41F987AF3"); /* s */
+
+  test_gostdsa (nettle_get_gost_gc512a(),
+	      "03A36340A95BB5F93D131961B5B1C1B3213DF7FF3B5A30376407E2A65C441BC6"
+	      "D1B34662317083243F007B15A8512B526606D3B172B606DCE86DBD6F82DA3D40", /* x */
+
+	      "DEAD76318012FED79507809C89CC44848743640EAC9A3C847DA9082E050760A1"
+	      "0679F4B707ABC1872640AD20D7441F66C7A8B3BFF1B8E11B4A076F0A86749F73", /* y */
+
+	      SHEX("EDC257BED45FDDE4F1457B7F5B19017A8F204184366689D938532CDBAA5CB29A"
+		   "1D369DA57F8B983BE272219BD2C9A4FC57ECF7A77F34EE2E8AA553976A4766C0"), /* h */
+
+	      "891AA75C2A6F3B4DE27E3903F61CBB0F3F85A4E3C62F39A6E4E84A7477679C6E"
+	      "45008DC2774CA2FF64C12C0606FF918CAE3A50115440E9BF2971B627A882A1E8", /* r */
+
+	      "31065479996DDBDEE180AFE22CA3CDC44B45CE4C6C83909D1D3B702922A32441"
+	      "A9E11DCFBEA3D847C06B1A8A38EB1671D6C82FA21B79C99BE2EA809B10DAA5DF"); /* s */
+}