1 files changed, 791 insertions, 0 deletions

diff --git a/src/util/crypto_hash.c b/src/util/crypto_hash.c
new file mode 100644
index 000000000..139496eac
--- /dev/null
+++ b/src/util/crypto_hash.c
@@ -0,0 +1,791 @@
+/*
+     This file is part of GNUnet.
+     (C) 2001, 2002, 2003, 2004, 2005, 2006, 2009 Christian Grothoff (and other contributing authors)
+
+     GNUnet is free software; you can redistribute it and/or modify
+     it under the terms of the GNU General Public License as published
+     by the Free Software Foundation; either version 2, 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
+     General Public License for more details.
+
+     You should have received a copy of the GNU General Public License
+     along with GNUnet; see the file COPYING.  If not, write to the
+     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+     Boston, MA 02111-1307, USA.
+
+     SHA-512 code by Jean-Luc Cooke <jlcooke@certainkey.com>
+
+     Copyright (c) Jean-Luc Cooke <jlcooke@certainkey.com>
+     Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
+     Copyright (c) 2003 Kyle McMartin <kyle@debian.org>
+*/
+
+/**
+ * @file util/crypto_hash.c
+ * @brief SHA-512 GNUNET_CRYPTO_hash related functions
+ * @author Christian Grothoff
+ */
+
+#include "platform.h"
+#include "gnunet_common.h"
+#include "gnunet_crypto_lib.h"
+#include "gnunet_disk_lib.h"
+
+#define SHA512_DIGEST_SIZE 64
+#define SHA512_HMAC_BLOCK_SIZE 128
+
+struct sha512_ctx
+{
+  unsigned long long state[8];
+  unsigned int count[4];
+  unsigned char buf[128];
+};
+
+static unsigned long long
+Ch (unsigned long long x, unsigned long long y, unsigned long long z)
+{
+  return z ^ (x & (y ^ z));
+}
+
+static unsigned long long
+Maj (unsigned long long x, unsigned long long y, unsigned long long z)
+{
+  return (x & y) | (z & (x | y));
+}
+
+static unsigned long long
+RORu64 (unsigned long long x, unsigned long long y)
+{
+  return (x >> y) | (x << (64 - y));
+}
+
+const unsigned long long sha512_K[80] = {
+  0x428a2f98d728ae22ULL, 0x7137449123ef65cdULL, 0xb5c0fbcfec4d3b2fULL,
+  0xe9b5dba58189dbbcULL, 0x3956c25bf348b538ULL, 0x59f111f1b605d019ULL,
+  0x923f82a4af194f9bULL, 0xab1c5ed5da6d8118ULL, 0xd807aa98a3030242ULL,
+  0x12835b0145706fbeULL, 0x243185be4ee4b28cULL, 0x550c7dc3d5ffb4e2ULL,
+  0x72be5d74f27b896fULL, 0x80deb1fe3b1696b1ULL, 0x9bdc06a725c71235ULL,
+  0xc19bf174cf692694ULL, 0xe49b69c19ef14ad2ULL, 0xefbe4786384f25e3ULL,
+  0x0fc19dc68b8cd5b5ULL, 0x240ca1cc77ac9c65ULL, 0x2de92c6f592b0275ULL,
+  0x4a7484aa6ea6e483ULL, 0x5cb0a9dcbd41fbd4ULL, 0x76f988da831153b5ULL,
+  0x983e5152ee66dfabULL, 0xa831c66d2db43210ULL, 0xb00327c898fb213fULL,
+  0xbf597fc7beef0ee4ULL, 0xc6e00bf33da88fc2ULL, 0xd5a79147930aa725ULL,
+  0x06ca6351e003826fULL, 0x142929670a0e6e70ULL, 0x27b70a8546d22ffcULL,
+  0x2e1b21385c26c926ULL, 0x4d2c6dfc5ac42aedULL, 0x53380d139d95b3dfULL,
+  0x650a73548baf63deULL, 0x766a0abb3c77b2a8ULL, 0x81c2c92e47edaee6ULL,
+  0x92722c851482353bULL, 0xa2bfe8a14cf10364ULL, 0xa81a664bbc423001ULL,
+  0xc24b8b70d0f89791ULL, 0xc76c51a30654be30ULL, 0xd192e819d6ef5218ULL,
+  0xd69906245565a910ULL, 0xf40e35855771202aULL, 0x106aa07032bbd1b8ULL,
+  0x19a4c116b8d2d0c8ULL, 0x1e376c085141ab53ULL, 0x2748774cdf8eeb99ULL,
+  0x34b0bcb5e19b48a8ULL, 0x391c0cb3c5c95a63ULL, 0x4ed8aa4ae3418acbULL,
+  0x5b9cca4f7763e373ULL, 0x682e6ff3d6b2b8a3ULL, 0x748f82ee5defb2fcULL,
+  0x78a5636f43172f60ULL, 0x84c87814a1f0ab72ULL, 0x8cc702081a6439ecULL,
+  0x90befffa23631e28ULL, 0xa4506cebde82bde9ULL, 0xbef9a3f7b2c67915ULL,
+  0xc67178f2e372532bULL, 0xca273eceea26619cULL, 0xd186b8c721c0c207ULL,
+  0xeada7dd6cde0eb1eULL, 0xf57d4f7fee6ed178ULL, 0x06f067aa72176fbaULL,
+  0x0a637dc5a2c898a6ULL, 0x113f9804bef90daeULL, 0x1b710b35131c471bULL,
+  0x28db77f523047d84ULL, 0x32caab7b40c72493ULL, 0x3c9ebe0a15c9bebcULL,
+  0x431d67c49c100d4cULL, 0x4cc5d4becb3e42b6ULL, 0x597f299cfc657e2aULL,
+  0x5fcb6fab3ad6faecULL, 0x6c44198c4a475817ULL,
+};
+
+#define e0(x)       (RORu64(x,28) ^ RORu64(x,34) ^ RORu64(x,39))
+#define e1(x)       (RORu64(x,14) ^ RORu64(x,18) ^ RORu64(x,41))
+#define s0(x)       (RORu64(x, 1) ^ RORu64(x, 8) ^ (x >> 7))
+#define s1(x)       (RORu64(x,19) ^ RORu64(x,61) ^ (x >> 6))
+
+/* H* initial state for SHA-512 */
+#define H0         0x6a09e667f3bcc908ULL
+#define H1         0xbb67ae8584caa73bULL
+#define H2         0x3c6ef372fe94f82bULL
+#define H3         0xa54ff53a5f1d36f1ULL
+#define H4         0x510e527fade682d1ULL
+#define H5         0x9b05688c2b3e6c1fULL
+#define H6         0x1f83d9abfb41bd6bULL
+#define H7         0x5be0cd19137e2179ULL
+
+/* H'* initial state for SHA-384 */
+#define HP0 0xcbbb9d5dc1059ed8ULL
+#define HP1 0x629a292a367cd507ULL
+#define HP2 0x9159015a3070dd17ULL
+#define HP3 0x152fecd8f70e5939ULL
+#define HP4 0x67332667ffc00b31ULL
+#define HP5 0x8eb44a8768581511ULL
+#define HP6 0xdb0c2e0d64f98fa7ULL
+#define HP7 0x47b5481dbefa4fa4ULL
+
+#define LOAD_OP(t1, I, W, input) \
+  t1  = input[(8*I)  ] & 0xff;\
+  t1 <<= 8;\
+  t1 |= input[(8*I)+1] & 0xff;\
+  t1 <<= 8;\
+  t1 |= input[(8*I)+2] & 0xff;\
+  t1 <<= 8;\
+  t1 |= input[(8*I)+3] & 0xff;\
+  t1 <<= 8;\
+  t1 |= input[(8*I)+4] & 0xff;\
+  t1 <<= 8;\
+  t1 |= input[(8*I)+5] & 0xff;\
+  t1 <<= 8;\
+  t1 |= input[(8*I)+6] & 0xff;\
+  t1 <<= 8;\
+  t1 |= input[(8*I)+7] & 0xff;\
+  W[I] = t1;
+
+
+#define BLEND_OP(I, W) \
+  W[I] = s1(W[I-2]) + W[I-7] + s0(W[I-15]) + W[I-16];
+
+static void
+sha512_transform (unsigned long long *state, const unsigned char *input)
+{
+  unsigned long long a, b, c, d, e, f, g, h, t1, t2;
+  unsigned long long W[80];
+  unsigned long long t0;
+  int i;
+
+  /* load the input */
+  for (i = 0; i < 16; i++)
+    {
+      LOAD_OP (t0, i, W, input);
+    }
+
+  for (i = 16; i < 80; i++)
+    {
+      BLEND_OP (i, W);
+    }
+
+  /* load the state into our registers */
+  a = state[0];
+  b = state[1];
+  c = state[2];
+  d = state[3];
+  e = state[4];
+  f = state[5];
+  g = state[6];
+  h = state[7];
+
+  /* now iterate */
+  for (i = 0; i < 80; i += 8)
+    {
+      t1 = h + e1 (e) + Ch (e, f, g) + sha512_K[i] + W[i];
+      t2 = e0 (a) + Maj (a, b, c);
+      d += t1;
+      h = t1 + t2;
+      t1 = g + e1 (d) + Ch (d, e, f) + sha512_K[i + 1] + W[i + 1];
+      t2 = e0 (h) + Maj (h, a, b);
+      c += t1;
+      g = t1 + t2;
+      t1 = f + e1 (c) + Ch (c, d, e) + sha512_K[i + 2] + W[i + 2];
+      t2 = e0 (g) + Maj (g, h, a);
+      b += t1;
+      f = t1 + t2;
+      t1 = e + e1 (b) + Ch (b, c, d) + sha512_K[i + 3] + W[i + 3];
+      t2 = e0 (f) + Maj (f, g, h);
+      a += t1;
+      e = t1 + t2;
+      t1 = d + e1 (a) + Ch (a, b, c) + sha512_K[i + 4] + W[i + 4];
+      t2 = e0 (e) + Maj (e, f, g);
+      h += t1;
+      d = t1 + t2;
+      t1 = c + e1 (h) + Ch (h, a, b) + sha512_K[i + 5] + W[i + 5];
+      t2 = e0 (d) + Maj (d, e, f);
+      g += t1;
+      c = t1 + t2;
+      t1 = b + e1 (g) + Ch (g, h, a) + sha512_K[i + 6] + W[i + 6];
+      t2 = e0 (c) + Maj (c, d, e);
+      f += t1;
+      b = t1 + t2;
+      t1 = a + e1 (f) + Ch (f, g, h) + sha512_K[i + 7] + W[i + 7];
+      t2 = e0 (b) + Maj (b, c, d);
+      e += t1;
+      a = t1 + t2;
+    }
+
+  state[0] += a;
+  state[1] += b;
+  state[2] += c;
+  state[3] += d;
+  state[4] += e;
+  state[5] += f;
+  state[6] += g;
+  state[7] += h;
+
+  /* erase our data */
+  a = b = c = d = e = f = g = h = t1 = t2 = 0;
+  memset (W, 0, 80 * sizeof (unsigned long long));
+}
+
+static void
+sha512_init (struct sha512_ctx *sctx)
+{
+  sctx->state[0] = H0;
+  sctx->state[1] = H1;
+  sctx->state[2] = H2;
+  sctx->state[3] = H3;
+  sctx->state[4] = H4;
+  sctx->state[5] = H5;
+  sctx->state[6] = H6;
+  sctx->state[7] = H7;
+  sctx->count[0] = sctx->count[1] = sctx->count[2] = sctx->count[3] = 0;
+  memset (sctx->buf, 0, sizeof (sctx->buf));
+}
+
+static void
+sha512_update (struct sha512_ctx *sctx,
+               const unsigned char *data, unsigned int len)
+{
+  unsigned int i, index, part_len;
+
+  /* Compute number of bytes mod 128 */
+  index = (unsigned int) ((sctx->count[0] >> 3) & 0x7F);
+
+  /* Update number of bits */
+  if ((sctx->count[0] += (len << 3)) < (len << 3))
+    {
+      if ((sctx->count[1] += 1) < 1)
+        if ((sctx->count[2] += 1) < 1)
+          sctx->count[3]++;
+      sctx->count[1] += (len >> 29);
+    }
+
+  part_len = 128 - index;
+
+  /* Transform as many times as possible. */
+  if (len >= part_len)
+    {
+      memcpy (&sctx->buf[index], data, part_len);
+      sha512_transform (sctx->state, sctx->buf);
+
+      for (i = part_len; i + 127 < len; i += 128)
+        sha512_transform (sctx->state, &data[i]);
+
+      index = 0;
+    }
+  else
+    {
+      i = 0;
+    }
+
+  /* Buffer remaining input */
+  memcpy (&sctx->buf[index], &data[i], len - i);
+}
+
+static void
+sha512_final (struct sha512_ctx *sctx, unsigned char *hash)
+{
+  static unsigned char padding[128] = { 0x80, };
+
+  unsigned int t;
+  unsigned long long t2;
+  unsigned char bits[128];
+  unsigned int index, pad_len;
+  int i, j;
+
+  index = pad_len = t = i = j = 0;
+  t2 = 0;
+
+  /* Save number of bits */
+  t = sctx->count[0];
+  bits[15] = t;
+  t >>= 8;
+  bits[14] = t;
+  t >>= 8;
+  bits[13] = t;
+  t >>= 8;
+  bits[12] = t;
+  t = sctx->count[1];
+  bits[11] = t;
+  t >>= 8;
+  bits[10] = t;
+  t >>= 8;
+  bits[9] = t;
+  t >>= 8;
+  bits[8] = t;
+  t = sctx->count[2];
+  bits[7] = t;
+  t >>= 8;
+  bits[6] = t;
+  t >>= 8;
+  bits[5] = t;
+  t >>= 8;
+  bits[4] = t;
+  t = sctx->count[3];
+  bits[3] = t;
+  t >>= 8;
+  bits[2] = t;
+  t >>= 8;
+  bits[1] = t;
+  t >>= 8;
+  bits[0] = t;
+
+  /* Pad out to 112 mod 128. */
+  index = (sctx->count[0] >> 3) & 0x7f;
+  pad_len = (index < 112) ? (112 - index) : ((128 + 112) - index);
+  sha512_update (sctx, padding, pad_len);
+
+  /* Append length (before padding) */
+  sha512_update (sctx, bits, 16);
+
+  /* Store state in digest */
+  for (i = j = 0; i < 8; i++, j += 8)
+    {
+      t2 = sctx->state[i];
+      hash[j + 7] = (char) t2 & 0xff;
+      t2 >>= 8;
+      hash[j + 6] = (char) t2 & 0xff;
+      t2 >>= 8;
+      hash[j + 5] = (char) t2 & 0xff;
+      t2 >>= 8;
+      hash[j + 4] = (char) t2 & 0xff;
+      t2 >>= 8;
+      hash[j + 3] = (char) t2 & 0xff;
+      t2 >>= 8;
+      hash[j + 2] = (char) t2 & 0xff;
+      t2 >>= 8;
+      hash[j + 1] = (char) t2 & 0xff;
+      t2 >>= 8;
+      hash[j] = (char) t2 & 0xff;
+    }
+
+  /* Zeroize sensitive information. */
+  memset (sctx, 0, sizeof (struct sha512_ctx));
+}
+
+/**
+ * Hash block of given size.
+ *
+ * @param block the data to GNUNET_CRYPTO_hash, length is given as a second argument
+ * @param size the length of the data to GNUNET_CRYPTO_hash
+ * @param ret pointer to where to write the hashcode
+ */
+void
+GNUNET_CRYPTO_hash (const void *block, unsigned int size,
+                    GNUNET_HashCode * ret)
+{
+  struct sha512_ctx ctx;
+
+  sha512_init (&ctx);
+  sha512_update (&ctx, block, size);
+  sha512_final (&ctx, (unsigned char *) ret);
+}
+
+
+/**
+ * Context used when hashing a file.
+ */
+struct FileHashContext
+{
+
+  /**
+   * Function to call upon completion.
+   */
+  GNUNET_CRYPTO_HashCompletedCallback callback;
+
+  /**
+   * Closure for callback.
+   */
+  void *callback_cls;
+
+  /**
+   * IO buffer.
+   */
+  unsigned char *buffer;
+
+  /**
+   * Name of the file we are hashing.
+   */
+  char *filename;
+
+  /**
+   * Cummulated hash.
+   */
+  struct sha512_ctx hctx;
+
+  /**
+   * Blocksize.
+   */
+  size_t bsize;
+
+  /**
+   * Size of the file.
+   */
+  unsigned long long fsize;
+
+  /**
+   * Current offset.
+   */
+  unsigned long long offset;
+
+  /**
+   * Run on shutdown?
+   */
+  int run_on_shutdown;
+
+  /**
+   * File descriptor.
+   */
+  int fd;
+
+};
+
+
+/**
+ * Report result of hash computation to callback
+ * and free associated resources.
+ */
+static void
+file_hash_finish (struct FileHashContext *fhc, const GNUNET_HashCode * res)
+{
+  fhc->callback (fhc->callback_cls, res);
+  GNUNET_free (fhc->filename);
+  if (fhc->fd != -1)
+    GNUNET_break (0 == CLOSE (fhc->fd));
+  GNUNET_free (fhc);            /* also frees fhc->buffer */
+}
+
+
+/**
+ * File hashing task.
+ *
+ * @param cls closure
+ * @param tc context
+ */
+static void
+file_hash_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  struct FileHashContext *fhc = cls;
+  GNUNET_HashCode res;
+  size_t delta;
+
+  GNUNET_assert (fhc->offset < fhc->fsize);
+  delta = fhc->bsize;
+  if (fhc->fsize - fhc->offset < delta)
+    delta = fhc->fsize - fhc->offset;
+  if (delta != READ (fhc->fd, fhc->buffer, delta))
+    {
+      GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
+                                "read", fhc->filename);
+      file_hash_finish (fhc, NULL);
+      return;
+    }
+  sha512_update (&fhc->hctx, fhc->buffer, delta);
+  fhc->offset += delta;
+  if (fhc->offset == fhc->fsize)
+    {
+      sha512_final (&fhc->hctx, (unsigned char *) &res);
+      file_hash_finish (fhc, &res);
+      return;
+    }
+  GNUNET_SCHEDULER_add_after (tc->sched,
+                              fhc->run_on_shutdown,
+                              GNUNET_SCHEDULER_PRIORITY_KEEP,
+                              GNUNET_SCHEDULER_NO_PREREQUISITE_TASK,
+                              &file_hash_task, fhc);
+}
+
+
+/**
+ * Compute the hash of an entire file.
+ *
+ * @param sched scheduler to use
+ * @param priority scheduling priority to use
+ * @param run_on_shutdown should we complete even on shutdown?
+ * @param filename name of file to hash
+ * @param blocksize number of bytes to process in one task
+ * @param callback function to call upon completion
+ * @param callback_cls closure for callback
+ */
+void
+GNUNET_CRYPTO_hash_file (struct GNUNET_SCHEDULER_Handle *sched,
+                         enum GNUNET_SCHEDULER_Priority priority,
+                         int run_on_shutdown,
+                         const char *filename,
+                         size_t blocksize,
+                         GNUNET_CRYPTO_HashCompletedCallback callback,
+                         void *callback_cls)
+{
+  struct FileHashContext *fhc;
+
+  GNUNET_assert (blocksize > 0);
+  fhc = GNUNET_malloc (sizeof (struct FileHashContext) + blocksize);
+  fhc->callback = callback;
+  fhc->callback_cls = callback_cls;
+  fhc->buffer = (unsigned char *) &fhc[1];
+  fhc->filename = GNUNET_strdup (filename);
+  fhc->fd = -1;
+  sha512_init (&fhc->hctx);
+  fhc->bsize = blocksize;
+  if (GNUNET_OK != GNUNET_DISK_file_size (filename, &fhc->fsize, GNUNET_NO))
+    {
+      file_hash_finish (fhc, NULL);
+      return;
+    }
+  fhc->run_on_shutdown = run_on_shutdown;
+  fhc->fd = GNUNET_DISK_file_open (filename, O_RDONLY | O_LARGEFILE);
+  if (fhc->fd == -1)
+    {
+      file_hash_finish (fhc, NULL);
+      return;
+    }
+  GNUNET_SCHEDULER_add_after (sched,
+                              run_on_shutdown,
+                              priority,
+                              GNUNET_SCHEDULER_NO_PREREQUISITE_TASK,
+                              &file_hash_task, fhc);
+}
+
+
+/* ***************** binary-ASCII encoding *************** */
+
+/**
+ * 32 characters for encoding (GNUNET_CRYPTO_hash => 32 characters)
+ */
+static char *encTable__ = "0123456789ABCDEFGHIJKLMNOPQRSTUV";
+
+static unsigned int
+getValue__ (unsigned char a)
+{
+  if ((a >= '0') && (a <= '9'))
+    return a - '0';
+  if ((a >= 'A') && (a <= 'V'))
+    return (a - 'A' + 10);
+  return -1;
+}
+
+/**
+ * Convert GNUNET_CRYPTO_hash to ASCII encoding.  The ASCII encoding is rather
+ * GNUnet specific.  It was chosen such that it only uses characters
+ * in [0-9A-V], can be produced without complex arithmetics and uses a
+ * small number of characters.  The GNUnet encoding uses 102
+ * characters plus a null terminator.
+ *
+ * @param block the GNUNET_CRYPTO_hash code
+ * @param result where to store the encoding (struct GNUNET_CRYPTO_HashAsciiEncoded can be
+ *  safely cast to char*, a '\0' termination is set).
+ */
+void
+GNUNET_CRYPTO_hash_to_enc (const GNUNET_HashCode * block,
+                           struct GNUNET_CRYPTO_HashAsciiEncoded *result)
+{
+  unsigned int wpos;
+  unsigned int rpos;
+  unsigned int bits;
+  unsigned int vbit;
+
+  GNUNET_assert (block != NULL);
+  GNUNET_assert (result != NULL);
+  vbit = 0;
+  wpos = 0;
+  rpos = 0;
+  bits = 0;
+  while ((rpos < sizeof (GNUNET_HashCode)) || (vbit > 0))
+    {
+      if ((rpos < sizeof (GNUNET_HashCode)) && (vbit < 5))
+        {
+          bits = (bits << 8) | ((unsigned char *) block)[rpos++];       /* eat 8 more bits */
+          vbit += 8;
+        }
+      if (vbit < 5)
+        {
+          bits <<= (5 - vbit);  /* zero-padding */
+          GNUNET_assert (vbit == 2);    /* padding by 3: 512+3 mod 5 == 0 */
+          vbit = 5;
+        }
+      GNUNET_assert (wpos <
+                     sizeof (struct GNUNET_CRYPTO_HashAsciiEncoded) - 1);
+      result->encoding[wpos++] = encTable__[(bits >> (vbit - 5)) & 31];
+      vbit -= 5;
+    }
+  GNUNET_assert (wpos == sizeof (struct GNUNET_CRYPTO_HashAsciiEncoded) - 1);
+  GNUNET_assert (vbit == 0);
+  result->encoding[wpos] = '\0';
+}
+
+/**
+ * Convert ASCII encoding back to GNUNET_CRYPTO_hash
+ *
+ * @param enc the encoding
+ * @param result where to store the GNUNET_CRYPTO_hash code
+ * @return GNUNET_OK on success, GNUNET_SYSERR if result has the wrong encoding
+ */
+int
+GNUNET_CRYPTO_hash_from_string (const char *enc, GNUNET_HashCode * result)
+{
+  unsigned int rpos;
+  unsigned int wpos;
+  unsigned int bits;
+  unsigned int vbit;
+
+  if (strlen (enc) != sizeof (struct GNUNET_CRYPTO_HashAsciiEncoded) - 1)
+    return GNUNET_SYSERR;
+
+  vbit = 2;                     /* padding! */
+  wpos = sizeof (GNUNET_HashCode);
+  rpos = sizeof (struct GNUNET_CRYPTO_HashAsciiEncoded) - 1;
+  bits = getValue__ (enc[--rpos]) >> 3;
+  while (wpos > 0)
+    {
+      GNUNET_assert (rpos > 0);
+      bits = (getValue__ (enc[--rpos]) << vbit) | bits;
+      vbit += 5;
+      if (vbit >= 8)
+        {
+          ((unsigned char *) result)[--wpos] = (unsigned char) bits;
+          bits >>= 8;
+          vbit -= 8;
+        }
+    }
+  GNUNET_assert (rpos == 0);
+  GNUNET_assert (vbit == 0);
+  return GNUNET_OK;
+}
+
+/**
+ * Compute the distance between 2 hashcodes.  The computation must be
+ * fast, not involve bits[0] or bits[4] (they're used elsewhere), and be
+ * somewhat consistent. And of course, the result should be a positive
+ * number.
+ *
+ * @returns a positive number which is a measure for
+ *  hashcode proximity.
+ */
+unsigned int
+GNUNET_CRYPTO_hash_distance_u32 (const GNUNET_HashCode * a,
+                                 const GNUNET_HashCode * b)
+{
+  unsigned int x1 = (a->bits[1] - b->bits[1]) >> 16;
+  unsigned int x2 = (b->bits[1] - a->bits[1]) >> 16;
+  return (x1 * x2);
+}
+
+void
+GNUNET_CRYPTO_hash_create_random (GNUNET_HashCode * result)
+{
+  int i;
+  for (i = (sizeof (GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0;
+       i--)
+    result->bits[i] = rand ();
+}
+
+void
+GNUNET_CRYPTO_hash_difference (const GNUNET_HashCode * a,
+                               const GNUNET_HashCode * b,
+                               GNUNET_HashCode * result)
+{
+  int i;
+  for (i = (sizeof (GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0;
+       i--)
+    result->bits[i] = b->bits[i] - a->bits[i];
+}
+
+void
+GNUNET_CRYPTO_hash_sum (const GNUNET_HashCode * a,
+                        const GNUNET_HashCode * delta,
+                        GNUNET_HashCode * result)
+{
+  int i;
+  for (i = (sizeof (GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0;
+       i--)
+    result->bits[i] = delta->bits[i] + a->bits[i];
+}
+
+void
+GNUNET_CRYPTO_hash_xor (const GNUNET_HashCode * a,
+                        const GNUNET_HashCode * b, GNUNET_HashCode * result)
+{
+  int i;
+  for (i = (sizeof (GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0;
+       i--)
+    result->bits[i] = a->bits[i] ^ b->bits[i];
+}
+
+/**
+ * Convert a hashcode into a key.
+ */
+void
+GNUNET_CRYPTO_hash_to_AES_key (const GNUNET_HashCode * hc,
+                               struct GNUNET_CRYPTO_AesSessionKey *skey,
+                               struct GNUNET_CRYPTO_AesInitializationVector
+                               *iv)
+{
+  GNUNET_assert (sizeof (GNUNET_HashCode) >=
+                 GNUNET_CRYPTO_AES_KEY_LENGTH +
+                 sizeof (struct GNUNET_CRYPTO_AesInitializationVector));
+  memcpy (skey, hc, GNUNET_CRYPTO_AES_KEY_LENGTH);
+  skey->crc32 =
+    htonl (GNUNET_CRYPTO_crc32_n (skey, GNUNET_CRYPTO_AES_KEY_LENGTH));
+  memcpy (iv, &((char *) hc)[GNUNET_CRYPTO_AES_KEY_LENGTH],
+          sizeof (struct GNUNET_CRYPTO_AesInitializationVector));
+}
+
+/**
+ * Obtain a bit from a hashcode.
+ * @param code the GNUNET_CRYPTO_hash to index bit-wise
+ * @param bit index into the hashcode, [0...511]
+ * @return Bit \a bit from hashcode \a code, -1 for invalid index
+ */
+int
+GNUNET_CRYPTO_hash_get_bit (const GNUNET_HashCode * code, unsigned int bit)
+{
+  GNUNET_assert (bit < 8 * sizeof (GNUNET_HashCode));
+  return (((unsigned char *) code)[bit >> 3] & (1 << (bit & 7))) > 0;
+}
+
+/**
+ * Compare function for HashCodes, producing a total ordering
+ * of all hashcodes.
+ * @return 1 if h1 > h2, -1 if h1 < h2 and 0 if h1 == h2.
+ */
+int
+GNUNET_CRYPTO_hash_cmp (const GNUNET_HashCode * h1,
+                        const GNUNET_HashCode * h2)
+{
+  unsigned int *i1;
+  unsigned int *i2;
+  int i;
+
+  i1 = (unsigned int *) h1;
+  i2 = (unsigned int *) h2;
+  for (i = (sizeof (GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0;
+       i--)
+    {
+      if (i1[i] > i2[i])
+        return 1;
+      if (i1[i] < i2[i])
+        return -1;
+    }
+  return 0;
+}
+
+/**
+ * Find out which of the two GNUNET_CRYPTO_hash codes is closer to target
+ * in the XOR metric (Kademlia).
+ * @return -1 if h1 is closer, 1 if h2 is closer and 0 if h1==h2.
+ */
+int
+GNUNET_CRYPTO_hash_xorcmp (const GNUNET_HashCode * h1,
+                           const GNUNET_HashCode * h2,
+                           const GNUNET_HashCode * target)
+{
+  int i;
+  unsigned int d1;
+  unsigned int d2;
+
+  for (i = sizeof (GNUNET_HashCode) / sizeof (unsigned int) - 1; i >= 0; i--)
+    {
+      d1 = ((unsigned int *) h1)[i] ^ ((unsigned int *) target)[i];
+      d2 = ((unsigned int *) h2)[i] ^ ((unsigned int *) target)[i];
+      if (d1 > d2)
+        return 1;
+      else if (d1 < d2)
+        return -1;
+    }
+  return 0;
+}
+
+/* end of hashing.c */