[gnunet] branch master updated: create crypto_pow, in preparation for #3795

[gnunet]

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grothoff pushed a commit to branch master
in repository gnunet.

The following commit(s) were added to refs/heads/master by this push:
     new ea544ab2c create crypto_pow, in preparation for #3795
ea544ab2c is described below

commit ea544ab2cae7f4f969a705d33d10da1a004cbd70
Author: Christian Grothoff <address@hidden>
AuthorDate: Sat Nov 30 22:43:08 2019 +0100

    create crypto_pow, in preparation for #3795
---
 src/include/gnunet_crypto_lib.h | 13 +++++++++
 src/nse/gnunet-service-nse.c    | 27 ++-----------------
 src/util/Makefile.am            |  1 +
 src/util/crypto_pow.c           | 58 +++++++++++++++++++++++++++++++++++++++++
 src/util/gnunet-scrypt.c        | 25 +-----------------
 5 files changed, 75 insertions(+), 49 deletions(-)

diff --git a/src/include/gnunet_crypto_lib.h b/src/include/gnunet_crypto_lib.h
index 507705e50..4a42c5c74 100644
--- a/src/include/gnunet_crypto_lib.h
+++ b/src/include/gnunet_crypto_lib.h
@@ -654,6 +654,19 @@ GNUNET_CRYPTO_hash (const void *block,
                     struct GNUNET_HashCode *ret);
 
 
+/**
+ * Calculate the 'proof-of-work' hash (an expensive hash).
+ *
+ * @param buf data to hash
+ * @param buf_len number of bytes in @a buf
+ * @param result where to write the resulting hash
+ */
+void
+GNUNET_CRYPTO_pow_hash (const void *buf,
+                        size_t buf_len,
+                        struct GNUNET_HashCode *result);
+
+
 /**
  * Context for cummulative hashing.
  */
diff --git a/src/nse/gnunet-service-nse.c b/src/nse/gnunet-service-nse.c
index 3e72be1c5..3f04314a6 100644
--- a/src/nse/gnunet-service-nse.c
+++ b/src/nse/gnunet-service-nse.c
@@ -487,29 +487,6 @@ get_delay_randomization (uint32_t matching_bits)
 }
 
 
-/**
- * Calculate the 'proof-of-work' hash (an expensive hash).
- *
- * @param buf data to hash
- * @param buf_len number of bytes in @a buf
- * @param result where to write the resulting hash
- */
-static void
-pow_hash (const void *buf, size_t buf_len, struct GNUNET_HashCode *result)
-{
-  GNUNET_break (
-    0 == gcry_kdf_derive (buf,
-                          buf_len,
-                          GCRY_KDF_SCRYPT,
-                          1 /* subalgo */,
-                          "gnunet-proof-of-work",
-                          strlen ("gnunet-proof-of-work"),
-                          2 /* iterations; keep cost of individual op small */,
-                          sizeof(struct GNUNET_HashCode),
-                          result));
-}
-
-
 /**
  * Get the number of matching bits that the given timestamp has to the given 
peer ID.
  *
@@ -828,7 +805,7 @@ check_proof_of_work (const struct 
GNUNET_CRYPTO_EddsaPublicKey *pkey,
   GNUNET_memcpy (&buf[sizeof(val)],
                  pkey,
                  sizeof(struct GNUNET_CRYPTO_EddsaPublicKey));
-  pow_hash (buf, sizeof(buf), &result);
+  GNUNET_CRYPTO_pow_hash (buf, sizeof(buf), &result);
   return (count_leading_zeroes (&result) >= nse_work_required) ? GNUNET_YES
          : GNUNET_NO;
 }
@@ -880,7 +857,7 @@ find_proof (void *cls)
   while ((counter != UINT64_MAX) && (i < ROUND_SIZE))
   {
     GNUNET_memcpy (buf, &counter, sizeof(uint64_t));
-    pow_hash (buf, sizeof(buf), &result);
+    GNUNET_CRYPTO_pow_hash (buf, sizeof(buf), &result);
     if (nse_work_required <= count_leading_zeroes (&result))
     {
       my_proof = counter;
diff --git a/src/util/Makefile.am b/src/util/Makefile.am
index 67e131810..0f6251f96 100644
--- a/src/util/Makefile.am
+++ b/src/util/Makefile.am
@@ -64,6 +64,7 @@ libgnunetutil_la_SOURCES = \
   crypto_kdf.c \
   crypto_mpi.c \
   crypto_paillier.c \
+  crypto_pow.c \
   crypto_random.c \
   crypto_rsa.c \
   disk.c \
diff --git a/src/util/crypto_pow.c b/src/util/crypto_pow.c
new file mode 100644
index 000000000..b4dfbf53a
--- /dev/null
+++ b/src/util/crypto_pow.c
@@ -0,0 +1,58 @@
+/*
+     This file is part of GNUnet.
+     Copyright (C) 2012, 2013, 2019 GNUnet e.V.
+
+     GNUnet is free software: you can redistribute it and/or modify it
+     under the terms of the GNU Affero General Public License as published
+     by the Free Software Foundation, either version 3 of the License,
+     or (at your option) any later version.
+
+     GNUnet is distributed in the hope that it will be useful, but
+     WITHOUT ANY WARRANTY; without even the implied warranty of
+     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+     Affero General Public License for more details.
+
+     You should have received a copy of the GNU Affero General Public License
+     along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+/**
+ * @file util/crypto_pow.c
+ * @brief proof-of-work hashing
+ * @author Christian Grothoff
+ * @author Bart Polot
+ */
+
+#include "platform.h"
+#include "gnunet_crypto_lib.h"
+#include <gcrypt.h>
+
+
+/**
+ * Calculate the 'proof-of-work' hash (an expensive hash).
+ * We're using a non-standard formula to avoid issues with
+ * ASICs appearing (see #3795).
+ *
+ * @param buf data to hash
+ * @param buf_len number of bytes in @a buf
+ * @param result where to write the resulting hash
+ */
+void
+GNUNET_CRYPTO_pow_hash (const void *buf, size_t buf_len, struct
+                        GNUNET_HashCode *result)
+{
+  GNUNET_break (
+    0 == gcry_kdf_derive (buf,
+                          buf_len,
+                          GCRY_KDF_SCRYPT,
+                          1 /* subalgo */,
+                          "gnunet-proof-of-work",
+                          strlen ("gnunet-proof-of-work"),
+                          2 /* iterations; keep cost of individual op small */,
+                          sizeof(struct GNUNET_HashCode),
+                          result));
+}
+
+
+/* end of crypto_pow.c */
diff --git a/src/util/gnunet-scrypt.c b/src/util/gnunet-scrypt.c
index 8d8451950..d84f486a7 100644
--- a/src/util/gnunet-scrypt.c
+++ b/src/util/gnunet-scrypt.c
@@ -67,29 +67,6 @@ shutdown_task (void *cls)
 }
 
 
-/**
- * Calculate the 'proof-of-work' hash (an expensive hash).
- *
- * @param buf data to hash
- * @param buf_len number of bytes in @a buf
- * @param result where to write the resulting hash
- */
-static void
-pow_hash (const void *buf, size_t buf_len, struct GNUNET_HashCode *result)
-{
-  GNUNET_break (
-    0 == gcry_kdf_derive (buf,
-                          buf_len,
-                          GCRY_KDF_SCRYPT,
-                          1 /* subalgo */,
-                          "gnunet-proof-of-work",
-                          strlen ("gnunet-proof-of-work"),
-                          2 /* iterations; keep cost of individual op small */,
-                          sizeof(struct GNUNET_HashCode),
-                          result));
-}
-
-
 /**
  * Count the leading zeroes in hash.
  *
@@ -140,7 +117,7 @@ find_proof (void *cls)
   while ((counter != UINT64_MAX) && (i < ROUND_SIZE))
   {
     GNUNET_memcpy (buf, &counter, sizeof(uint64_t));
-    pow_hash (buf, sizeof(buf), &result);
+    GNUNET_CRYPTO_pow_hash (buf, sizeof(buf), &result);
     if (nse_work_required <= count_leading_zeroes (&result))
     {
       proof = counter;

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