Implementation for a simple order-preserving encryption scheme.

This is meant for use when encrypting the current time within the
period in order to get a monotonically increasing revision counter
without actually revealing our view of the time.

This scheme is far from the most state-of-the-art: don't use it for
anything else without careful analysis by somebody much smarter than
I am.

See ticket #25552 for some rationale for this logic.

1 files changed, 148 insertions, 0 deletions

diff --git a/src/test/test_crypto_ope.c b/src/test/test_crypto_ope.c
new file mode 100644
index 0000000000..1b93e6981e
--- /dev/null
+++ b/src/test/test_crypto_ope.c
@@ -0,0 +1,148 @@
+/* Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2017, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "orconfig.h"
+
+#define CRYPTO_OPE_PRIVATE
+
+#include "lib/crypt_ops/crypto_ope.h"
+#include "common/util_format.h"
+#include "test/test.h"
+
+static void
+test_crypto_ope_consistency(void *arg)
+{
+  (void)arg;
+
+  crypto_ope_t *ope = NULL;
+  crypto_cipher_t *aes = NULL;
+  const int TEST_VALS[] = { 5, 500, 1023, 1024, 1025, 2046, 2047, 2048, 2049,
+                            10000, OPE_INPUT_MAX };
+  unsigned i;
+  const uint8_t key[32] = "A fixed key, chosen arbitrarily.";
+
+  ope = crypto_ope_new(key);
+  tt_assert(ope);
+
+  uint64_t last_val = 0;
+  for (i = 0; i < ARRAY_LENGTH(TEST_VALS); ++i) {
+    aes = ope_get_cipher(ope, 0);
+    int val = TEST_VALS[i];
+    uint64_t v1 = crypto_ope_encrypt(ope, val);
+    uint64_t v2 = sum_values_from_cipher(aes, val);
+    tt_u64_op(v1, OP_EQ, v2);
+    tt_u64_op(v2, OP_GT, last_val);
+    last_val = v2;
+    crypto_cipher_free(aes);
+  }
+
+ done:
+  crypto_cipher_free(aes);
+  crypto_ope_free(ope);
+}
+
+static void
+test_crypto_ope_oob(void *arg)
+{
+  (void)arg;
+
+  crypto_ope_t *ope = NULL;
+  const uint8_t key[32] = "A fixed key, chosen arbitrarily.";
+  ope = crypto_ope_new(key);
+
+  tt_u64_op(UINT64_MAX, OP_EQ, crypto_ope_encrypt(ope,INT_MIN));
+  tt_u64_op(UINT64_MAX, OP_EQ, crypto_ope_encrypt(ope,-100));
+  tt_u64_op(UINT64_MAX, OP_EQ, crypto_ope_encrypt(ope,0));
+  tt_u64_op(UINT64_MAX, OP_NE, crypto_ope_encrypt(ope,1));
+  tt_u64_op(UINT64_MAX, OP_NE, crypto_ope_encrypt(ope,7000));
+  tt_u64_op(UINT64_MAX, OP_NE, crypto_ope_encrypt(ope,OPE_INPUT_MAX));
+  tt_u64_op(UINT64_MAX, OP_EQ, crypto_ope_encrypt(ope,OPE_INPUT_MAX+1));
+  tt_u64_op(UINT64_MAX, OP_EQ, crypto_ope_encrypt(ope,INT_MAX));
+ done:
+  crypto_ope_free(ope);
+}
+
+static const char OPE_TEST_KEY[] =
+  "19e05891d55232c08c2cad91d612fdb9cbd6691949a0742434a76c80bc6992fe";
+
+/* generated by a separate python implementation. */
+static const struct {
+  int v;
+  uint64_t r;
+} OPE_TEST_VECTORS[] = {
+  { 121132, UINT64_C(3971694514) },
+  { 82283, UINT64_C(2695743564) },
+  { 72661, UINT64_C(2381548866) },
+  { 72941, UINT64_C(2390408421) },
+  { 123122, UINT64_C(4036781069) },
+  { 12154, UINT64_C(402067100) },
+  { 121574, UINT64_C(3986197593) },
+  { 11391, UINT64_C(376696838) },
+  { 65845, UINT64_C(2161801517) },
+  { 86301, UINT64_C(2828270975) },
+  { 61284, UINT64_C(2013616892) },
+  { 70505, UINT64_C(2313368870) },
+  { 30438, UINT64_C(1001394664) },
+  { 60150, UINT64_C(1977329668) },
+  { 114800, UINT64_C(3764946628) },
+  { 109403, UINT64_C(3585352477) },
+  { 21893, UINT64_C(721388468) },
+  { 123569, UINT64_C(4051780471) },
+  { 95617, UINT64_C(3134921876) },
+  { 48561, UINT64_C(1597596985) },
+  { 53334, UINT64_C(1753691710) },
+  { 92746, UINT64_C(3040874493) },
+  { 7110, UINT64_C(234966492) },
+  { 9612, UINT64_C(318326551) },
+  { 106958, UINT64_C(3506124249) },
+  { 46889, UINT64_C(1542219146) },
+  { 87790, UINT64_C(2877361609) },
+  { 68878, UINT64_C(2260369112) },
+  { 47917, UINT64_C(1576681737) },
+  { 121128, UINT64_C(3971553290) },
+  { 108602, UINT64_C(3559176081) },
+  { 28217, UINT64_C(929692460) },
+  { 69498, UINT64_C(2280554161) },
+  { 63870, UINT64_C(2098322675) },
+  { 57542, UINT64_C(1891698992) },
+  { 122148, UINT64_C(4004515805) },
+  { 46254, UINT64_C(1521227949) },
+  { 42850, UINT64_C(1408996941) },
+  { 92661, UINT64_C(3037901517) },
+  { 57720, UINT64_C(1897369989) },
+};
+
+static void
+test_crypto_ope_vectors(void *arg)
+{
+  (void)arg;
+  uint8_t key[32];
+  crypto_ope_t *ope = NULL, *ope2 = NULL;
+
+  base16_decode((char*)key, 32, OPE_TEST_KEY, strlen(OPE_TEST_KEY));
+
+  ope = crypto_ope_new(key);
+  key[8] += 1;
+  ope2 = crypto_ope_new(key);
+  unsigned i;
+  for (i = 0; i < ARRAY_LENGTH(OPE_TEST_VECTORS); ++i) {
+    int val = OPE_TEST_VECTORS[i].v;
+    uint64_t res = OPE_TEST_VECTORS[i].r;
+
+    tt_u64_op(crypto_ope_encrypt(ope, val), OP_EQ, res);
+    tt_u64_op(crypto_ope_encrypt(ope2, val), OP_NE, res);
+  }
+ done:
+  crypto_ope_free(ope);
+  crypto_ope_free(ope2);
+}
+
+struct testcase_t crypto_ope_tests[] = {
+  { "consistency", test_crypto_ope_consistency, 0, NULL, NULL },
+  { "oob", test_crypto_ope_oob, 0, NULL, NULL },
+  { "vectors", test_crypto_ope_vectors, 0, NULL, NULL },
+  END_OF_TESTCASES
+};
+