X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=src%2Futil%2Fcrypto_hash.c;h=2e436c4549cd4dd97e542278fd166b42044dcb30;hb=72c8645af31896829b674b575c5375706f362a30;hp=b8c9a80826fbd37de0830d6141da0bc413cfef60;hpb=d9d94d0e53d26af75ec8241383d166544ebd79f3;p=oweals%2Fgnunet.git

diff --git a/src/util/crypto_hash.c b/src/util/crypto_hash.c
index b8c9a8082..2e436c454 100644
--- a/src/util/crypto_hash.c
+++ b/src/util/crypto_hash.c
@@ -1,6 +1,6 @@
 /*
      This file is part of GNUnet.
-     (C) 2001, 2002, 2003, 2004, 2005, 2006, 2009 Christian Grothoff (and other contributing authors)
+     (C) 2001, 2002, 2003, 2004, 2005, 2006, 2009, 2012 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
@@ -34,6 +34,7 @@
 #include "gnunet_common.h"
 #include "gnunet_crypto_lib.h"
 #include "gnunet_disk_lib.h"
+#include "gnunet_strings_lib.h"
 #include <gcrypt.h>
 
 #define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)
@@ -48,12 +49,27 @@
  * @param ret pointer to where to write the hashcode
  */
 void
-GNUNET_CRYPTO_hash (const void *block, size_t size, GNUNET_HashCode * ret)
+GNUNET_CRYPTO_hash (const void *block, size_t size, struct GNUNET_HashCode * ret)
 {
   gcry_md_hash_buffer (GCRY_MD_SHA512, ret, block, size);
 }
 
 
+/**
+ * Compute short (256-bit) hash of a given block.
+ *
+ * @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_short_hash (const void *block, size_t size, 
+			  struct GNUNET_CRYPTO_ShortHashCode * ret)
+{
+  gcry_md_hash_buffer (GCRY_MD_SHA256, ret, block, size);
+}
+
+
 /**
  * Context used when hashing a file.
  */
@@ -105,6 +121,11 @@ struct GNUNET_CRYPTO_FileHashContext
    */
   GNUNET_SCHEDULER_TaskIdentifier task;
 
+  /**
+   * Priority we use.
+   */
+  enum GNUNET_SCHEDULER_Priority priority;
+
   /**
    * Blocksize.
    */
@@ -119,14 +140,14 @@ struct GNUNET_CRYPTO_FileHashContext
  */
 static void
 file_hash_finish (struct GNUNET_CRYPTO_FileHashContext *fhc,
-		  const GNUNET_HashCode * res)
+                  const struct GNUNET_HashCode * res)
 {
   fhc->callback (fhc->callback_cls, res);
   GNUNET_free (fhc->filename);
   if (!GNUNET_DISK_handle_invalid (fhc->fh))
     GNUNET_break (GNUNET_OK == GNUNET_DISK_file_close (fhc->fh));
   gcry_md_close (fhc->md);
-  GNUNET_free (fhc);		/* also frees fhc->buffer */
+  GNUNET_free (fhc);            /* also frees fhc->buffer */
 }
 
 
@@ -140,7 +161,7 @@ static void
 file_hash_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 {
   struct GNUNET_CRYPTO_FileHashContext *fhc = cls;
-  GNUNET_HashCode *res;
+  struct GNUNET_HashCode *res;
   size_t delta;
 
   fhc->task = GNUNET_SCHEDULER_NO_TASK;
@@ -149,20 +170,21 @@ file_hash_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
   if (fhc->fsize - fhc->offset < delta)
     delta = fhc->fsize - fhc->offset;
   if (delta != GNUNET_DISK_file_read (fhc->fh, fhc->buffer, delta))
-    {
-      LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "read", fhc->filename);
-      file_hash_finish (fhc, NULL);
-      return;
-    }
+  {
+    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "read", fhc->filename);
+    file_hash_finish (fhc, NULL);
+    return;
+  }
   gcry_md_write (fhc->md, fhc->buffer, delta);
   fhc->offset += delta;
   if (fhc->offset == fhc->fsize)
-    {
-      res = (GNUNET_HashCode *) gcry_md_read (fhc->md, GCRY_MD_SHA512);
-      file_hash_finish (fhc, res);
-      return;
-    }
-  fhc->task = GNUNET_SCHEDULER_add_now (&file_hash_task, fhc);
+  {
+    res = (struct GNUNET_HashCode *) gcry_md_read (fhc->md, GCRY_MD_SHA512);
+    file_hash_finish (fhc, res);
+    return;
+  }
+  fhc->task = GNUNET_SCHEDULER_add_with_priority (fhc->priority,
+						  &file_hash_task, fhc);
 }
 
 
@@ -178,43 +200,44 @@ file_hash_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
  */
 struct GNUNET_CRYPTO_FileHashContext *
 GNUNET_CRYPTO_hash_file (enum GNUNET_SCHEDULER_Priority priority,
-			 const char *filename, size_t blocksize,
-			 GNUNET_CRYPTO_HashCompletedCallback callback,
-			 void *callback_cls)
+                         const char *filename, size_t blocksize,
+                         GNUNET_CRYPTO_HashCompletedCallback callback,
+                         void *callback_cls)
 {
   struct GNUNET_CRYPTO_FileHashContext *fhc;
 
   GNUNET_assert (blocksize > 0);
   fhc =
-    GNUNET_malloc (sizeof (struct GNUNET_CRYPTO_FileHashContext) + blocksize);
+      GNUNET_malloc (sizeof (struct GNUNET_CRYPTO_FileHashContext) + blocksize);
   fhc->callback = callback;
   fhc->callback_cls = callback_cls;
   fhc->buffer = (unsigned char *) &fhc[1];
   fhc->filename = GNUNET_strdup (filename);
   if (GPG_ERR_NO_ERROR != gcry_md_open (&fhc->md, GCRY_MD_SHA512, 0))
-    {
-      GNUNET_break (0);
-      GNUNET_free (fhc);
-      return NULL;
-    }
+  {
+    GNUNET_break (0);
+    GNUNET_free (fhc);
+    return NULL;
+  }
   fhc->bsize = blocksize;
-  if (GNUNET_OK != GNUNET_DISK_file_size (filename, &fhc->fsize, GNUNET_NO))
-    {
-      GNUNET_free (fhc->filename);
-      GNUNET_free (fhc);
-      return NULL;
-    }
+  if (GNUNET_OK != GNUNET_DISK_file_size (filename, &fhc->fsize, GNUNET_NO, GNUNET_YES))
+  {
+    GNUNET_free (fhc->filename);
+    GNUNET_free (fhc);
+    return NULL;
+  }
   fhc->fh =
-    GNUNET_DISK_file_open (filename, GNUNET_DISK_OPEN_READ,
-			   GNUNET_DISK_PERM_NONE);
+      GNUNET_DISK_file_open (filename, GNUNET_DISK_OPEN_READ,
+                             GNUNET_DISK_PERM_NONE);
   if (!fhc->fh)
-    {
-      GNUNET_free (fhc->filename);
-      GNUNET_free (fhc);
-      return NULL;
-    }
+  {
+    GNUNET_free (fhc->filename);
+    GNUNET_free (fhc);
+    return NULL;
+  }
+  fhc->priority = priority;
   fhc->task =
-    GNUNET_SCHEDULER_add_with_priority (priority, &file_hash_task, fhc);
+      GNUNET_SCHEDULER_add_with_priority (priority, &file_hash_task, fhc);
   return fhc;
 }
 
@@ -234,18 +257,8 @@ GNUNET_CRYPTO_hash_file_cancel (struct GNUNET_CRYPTO_FileHashContext *fhc)
 }
 
 
-
 /* ***************** binary-ASCII encoding *************** */
 
-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
@@ -259,86 +272,43 @@ getValue__ (unsigned char a)
  *  safely cast to char*, a '\\0' termination is set).
  */
 void
-GNUNET_CRYPTO_hash_to_enc (const GNUNET_HashCode * block,
-			   struct GNUNET_CRYPTO_HashAsciiEncoded *result)
+GNUNET_CRYPTO_hash_to_enc (const struct GNUNET_HashCode * block,
+                           struct GNUNET_CRYPTO_HashAsciiEncoded *result)
 {
-  /**
-   * 32 characters for encoding (GNUNET_CRYPTO_hash => 32 characters)
-   */
-  static char *encTable__ = "0123456789ABCDEFGHIJKLMNOPQRSTUV";
-  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';
+  char *np;
+
+  np = GNUNET_STRINGS_data_to_string ((const unsigned char *) block,
+				      sizeof (struct GNUNET_HashCode),
+				      (char*) result,
+				      sizeof (struct GNUNET_CRYPTO_HashAsciiEncoded) - 1);
+  GNUNET_assert (NULL != np);
+  *np = '\0';
 }
 
+
 /**
- * Convert ASCII encoding back to GNUNET_CRYPTO_hash
+ * Convert ASCII encoding back to hash code.
  *
  * @param enc the encoding
- * @param result where to store the GNUNET_CRYPTO_hash code
+ * @param enclen number of characters in 'enc' (without 0-terminator, which can be missing)
+ * @param result where to store the 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)
+GNUNET_CRYPTO_hash_from_string2 (const char *enc, size_t enclen,
+                                struct GNUNET_HashCode * result)
 {
-  unsigned int rpos;
-  unsigned int wpos;
-  unsigned int bits;
-  unsigned int vbit;
+  char upper_enc[enclen];
+  char* up_ptr = upper_enc;
 
-  if (strlen (enc) != sizeof (struct GNUNET_CRYPTO_HashAsciiEncoded) - 1)
-    return GNUNET_SYSERR;
+  GNUNET_STRINGS_utf8_toupper(enc, &up_ptr);
 
-  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;
+  return GNUNET_STRINGS_string_to_data (upper_enc, enclen,
+					(unsigned char*) result,
+					sizeof (struct GNUNET_HashCode));
 }
 
+
 /**
  * Compute the distance between 2 hashcodes.  The computation must be
  * fast, not involve bits[0] or bits[4] (they're used elsewhere), and be
@@ -351,8 +321,8 @@ GNUNET_CRYPTO_hash_from_string (const char *enc, GNUNET_HashCode * result)
  *  hashcode proximity.
  */
 unsigned int
-GNUNET_CRYPTO_hash_distance_u32 (const GNUNET_HashCode * a,
-				 const GNUNET_HashCode * b)
+GNUNET_CRYPTO_hash_distance_u32 (const struct GNUNET_HashCode * a,
+                                 const struct GNUNET_HashCode * b)
 {
   unsigned int x1 = (a->bits[1] - b->bits[1]) >> 16;
   unsigned int x2 = (b->bits[1] - a->bits[1]) >> 16;
@@ -360,70 +330,97 @@ GNUNET_CRYPTO_hash_distance_u32 (const GNUNET_HashCode * a,
   return (x1 * x2);
 }
 
+
+/**
+ * Create a random hash code.
+ *
+ * @param mode desired quality level
+ * @param result hash code that is randomized
+ */
 void
 GNUNET_CRYPTO_hash_create_random (enum GNUNET_CRYPTO_Quality mode,
-				  GNUNET_HashCode * result)
+                                  struct GNUNET_HashCode *result)
 {
   int i;
 
-  for (i = (sizeof (GNUNET_HashCode) / sizeof (uint32_t)) - 1; i >= 0; i--)
+  for (i = (sizeof (struct GNUNET_HashCode) / sizeof (uint32_t)) - 1; i >= 0; i--)
     result->bits[i] = GNUNET_CRYPTO_random_u32 (mode, UINT32_MAX);
 }
 
+
+/**
+ * compute result(delta) = b - a
+ *
+ * @param a some hash code
+ * @param b some hash code
+ * @param result set to b - a
+ */
 void
-GNUNET_CRYPTO_hash_difference (const GNUNET_HashCode * a,
-			       const GNUNET_HashCode * b,
-			       GNUNET_HashCode * result)
+GNUNET_CRYPTO_hash_difference (const struct GNUNET_HashCode * a,
+                               const struct GNUNET_HashCode * b,
+                               struct GNUNET_HashCode * result)
 {
   int i;
 
-  for (i = (sizeof (GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0;
-       i--)
+  for (i = (sizeof (struct GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0; i--)
     result->bits[i] = b->bits[i] - a->bits[i];
 }
 
+
+/**
+ * compute result(b) = a + delta
+ *
+ * @param a some hash code
+ * @param delta some hash code
+ * @param result set to a + delta
+ */
 void
-GNUNET_CRYPTO_hash_sum (const GNUNET_HashCode * a,
-			const GNUNET_HashCode * delta,
-			GNUNET_HashCode * result)
+GNUNET_CRYPTO_hash_sum (const struct GNUNET_HashCode * a,
+                        const struct GNUNET_HashCode * delta, struct GNUNET_HashCode * result)
 {
   int i;
 
-  for (i = (sizeof (GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0;
-       i--)
+  for (i = (sizeof (struct GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0; i--)
     result->bits[i] = delta->bits[i] + a->bits[i];
 }
 
 
+/**
+ * compute result = a ^ b
+ *
+ * @param a some hash code
+ * @param b some hash code
+ * @param result set to a ^ b
+ */
 void
-GNUNET_CRYPTO_hash_xor (const GNUNET_HashCode * a, const GNUNET_HashCode * b,
-			GNUNET_HashCode * result)
+GNUNET_CRYPTO_hash_xor (const struct GNUNET_HashCode * a, const struct GNUNET_HashCode * b,
+                        struct GNUNET_HashCode * result)
 {
   int i;
 
-  for (i = (sizeof (GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0;
-       i--)
+  for (i = (sizeof (struct GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0; i--)
     result->bits[i] = a->bits[i] ^ b->bits[i];
 }
 
 
 /**
  * Convert a hashcode into a key.
+ *
+ * @param hc hash code that serves to generate the key
+ * @param skey set to a valid session key
+ * @param iv set to a valid initialization vector
  */
 void
-GNUNET_CRYPTO_hash_to_aes_key (const GNUNET_HashCode * hc,
-			       struct GNUNET_CRYPTO_AesSessionKey *skey,
-			       struct GNUNET_CRYPTO_AesInitializationVector
-			       *iv)
+GNUNET_CRYPTO_hash_to_aes_key (const struct 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));
+  GNUNET_assert (sizeof (struct 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));
+          sizeof (struct GNUNET_CRYPTO_AesInitializationVector));
 }
 
 
@@ -434,15 +431,16 @@ GNUNET_CRYPTO_hash_to_aes_key (const GNUNET_HashCode * hc,
  * @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_CRYPTO_hash_get_bit (const struct GNUNET_HashCode * code, unsigned int bit)
 {
-  GNUNET_assert (bit < 8 * sizeof (GNUNET_HashCode));
+  GNUNET_assert (bit < 8 * sizeof (struct GNUNET_HashCode));
   return (((unsigned char *) code)[bit >> 3] & (1 << (bit & 7))) > 0;
 }
 
+
 /**
  * Determine how many low order bits match in two
- * GNUNET_HashCodes.  i.e. - 010011 and 011111 share
+ * struct GNUNET_HashCodes.  i.e. - 010011 and 011111 share
  * the first two lowest order bits, and therefore the
  * return value is two (NOT XOR distance, nor how many
  * bits match absolutely!).
@@ -453,27 +451,29 @@ GNUNET_CRYPTO_hash_get_bit (const GNUNET_HashCode * code, unsigned int bit)
  * @return the number of bits that match
  */
 unsigned int
-GNUNET_CRYPTO_hash_matching_bits (const GNUNET_HashCode * first,
-				  const GNUNET_HashCode * second)
+GNUNET_CRYPTO_hash_matching_bits (const struct GNUNET_HashCode * first,
+                                  const struct GNUNET_HashCode * second)
 {
   unsigned int i;
 
-  for (i = 0; i < sizeof (GNUNET_HashCode) * 8; i++)
+  for (i = 0; i < sizeof (struct GNUNET_HashCode) * 8; i++)
     if (GNUNET_CRYPTO_hash_get_bit (first, i) !=
-	GNUNET_CRYPTO_hash_get_bit (second, i))
+        GNUNET_CRYPTO_hash_get_bit (second, i))
       return i;
-  return sizeof (GNUNET_HashCode) * 8;
+  return sizeof (struct GNUNET_HashCode) * 8;
 }
 
 
 /**
  * Compare function for HashCodes, producing a total ordering
  * of all hashcodes.
+ *
+ * @param h1 some hash code
+ * @param h2 some hash code
  * @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)
+GNUNET_CRYPTO_hash_cmp (const struct GNUNET_HashCode * h1, const struct GNUNET_HashCode * h2)
 {
   unsigned int *i1;
   unsigned int *i2;
@@ -481,14 +481,13 @@ GNUNET_CRYPTO_hash_cmp (const GNUNET_HashCode * h1,
 
   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;
-    }
+  for (i = (sizeof (struct 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;
 }
 
@@ -496,26 +495,30 @@ GNUNET_CRYPTO_hash_cmp (const GNUNET_HashCode * h1,
 /**
  * Find out which of the two GNUNET_CRYPTO_hash codes is closer to target
  * in the XOR metric (Kademlia).
+ *
+ * @param h1 some hash code
+ * @param h2 some hash code
+ * @param target some hash code
  * @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)
+GNUNET_CRYPTO_hash_xorcmp (const struct GNUNET_HashCode * h1,
+                           const struct GNUNET_HashCode * h2,
+                           const struct 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;
-    }
+  for (i = sizeof (struct 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;
 }
 
@@ -530,8 +533,8 @@ GNUNET_CRYPTO_hash_xorcmp (const GNUNET_HashCode * h1,
  */
 void
 GNUNET_CRYPTO_hmac_derive_key (struct GNUNET_CRYPTO_AuthKey *key,
-			       const struct GNUNET_CRYPTO_AesSessionKey *rkey,
-			       const void *salt, size_t salt_len, ...)
+                               const struct GNUNET_CRYPTO_AesSessionKey *rkey,
+                               const void *salt, size_t salt_len, ...)
 {
   va_list argp;
 
@@ -551,12 +554,12 @@ GNUNET_CRYPTO_hmac_derive_key (struct GNUNET_CRYPTO_AuthKey *key,
  */
 void
 GNUNET_CRYPTO_hmac_derive_key_v (struct GNUNET_CRYPTO_AuthKey *key,
-				 const struct GNUNET_CRYPTO_AesSessionKey
-				 *rkey, const void *salt, size_t salt_len,
-				 va_list argp)
+                                 const struct GNUNET_CRYPTO_AesSessionKey *rkey,
+                                 const void *salt, size_t salt_len,
+                                 va_list argp)
 {
   GNUNET_CRYPTO_kdf_v (key->key, sizeof (key->key), salt, salt_len, rkey->key,
-		       sizeof (rkey->key), argp);
+                       sizeof (rkey->key), argp);
 }
 
 
@@ -570,14 +573,14 @@ GNUNET_CRYPTO_hmac_derive_key_v (struct GNUNET_CRYPTO_AuthKey *key,
  */
 void
 GNUNET_CRYPTO_hmac (const struct GNUNET_CRYPTO_AuthKey *key,
-		    const void *plaintext, size_t plaintext_len,
-		    GNUNET_HashCode * hmac)
+                    const void *plaintext, size_t plaintext_len,
+                    struct GNUNET_HashCode * hmac)
 {
   gcry_md_hd_t md;
   const unsigned char *mc;
 
   GNUNET_assert (GPG_ERR_NO_ERROR ==
-		 gcry_md_open (&md, GCRY_MD_SHA512, GCRY_MD_FLAG_HMAC));
+                 gcry_md_open (&md, GCRY_MD_SHA512, GCRY_MD_FLAG_HMAC));
   gcry_md_setkey (md, key->key, sizeof (key->key));
   gcry_md_write (md, plaintext, plaintext_len);
   mc = gcry_md_read (md, GCRY_MD_SHA512);
@@ -587,4 +590,119 @@ GNUNET_CRYPTO_hmac (const struct GNUNET_CRYPTO_AuthKey *key,
 }
 
 
+
+/**
+ * Double short (256-bit) hash to create a long hash.
+ *
+ * @param sh short hash to double
+ * @param dh where to store the (doubled) long hash (not really a hash)
+ */
+void
+GNUNET_CRYPTO_short_hash_double (const struct GNUNET_CRYPTO_ShortHashCode *sh,
+				 struct GNUNET_HashCode *dh)
+{
+  char *ptr;
+
+  ptr = (char*) dh;
+  memcpy (ptr, sh, sizeof (struct GNUNET_CRYPTO_ShortHashCode));
+  memcpy (&ptr[sizeof (struct GNUNET_CRYPTO_ShortHashCode)], sh, sizeof (struct GNUNET_CRYPTO_ShortHashCode));
+}
+
+
+/**
+ * Truncate doubled short hash back to a short hash.
+ *
+ * @param dh doubled short hash to reduce again
+ * @param sh where to store the short hash
+ * @return GNUNET_OK on success, GNUNET_SYSERR if this was not a
+ *         doubled short hash
+ */
+int
+GNUNET_CRYPTO_short_hash_from_truncation (const struct GNUNET_HashCode *dh,
+					  struct GNUNET_CRYPTO_ShortHashCode *sh)
+{
+  const struct GNUNET_CRYPTO_ShortHashCode *s;
+
+  s = (const struct GNUNET_CRYPTO_ShortHashCode *) dh;
+  if (0 != memcmp (&s[0],
+		   &s[1],
+		   sizeof (struct GNUNET_CRYPTO_ShortHashCode)))
+    return GNUNET_SYSERR;
+  *sh = *s;
+  return GNUNET_OK;
+}
+
+
+/**
+ * Convert ASCII encoding back to a 'struct GNUNET_CRYPTO_ShortHash'
+ *
+ * @param enc the encoding
+ * @param enclen number of characters in 'enc' (without 0-terminator, which can be missing)
+ * @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_short_hash_from_string2 (const char *enc, size_t enclen,
+				       struct GNUNET_CRYPTO_ShortHashCode * result)
+{
+
+  char upper_enc[enclen];
+  char* up_ptr = upper_enc;
+
+  GNUNET_STRINGS_utf8_toupper(enc, &up_ptr);
+  return GNUNET_STRINGS_string_to_data (upper_enc, enclen,
+					(unsigned char*) result,
+					sizeof (struct GNUNET_CRYPTO_ShortHashCode));
+}
+
+
+/**
+ * Convert short hash to ASCII encoding.
+ *
+ * @param block the hash code
+ * @param result where to store the encoding (struct GNUNET_CRYPTO_ShortHashAsciiEncoded can be
+ *  safely cast to char*, a '\\0' termination is set).
+ */
+void
+GNUNET_CRYPTO_short_hash_to_enc (const struct GNUNET_CRYPTO_ShortHashCode * block,
+				 struct GNUNET_CRYPTO_ShortHashAsciiEncoded *result)
+{
+  char *np;
+
+  np = GNUNET_STRINGS_data_to_string ((const unsigned char *) block,
+				      sizeof (struct GNUNET_CRYPTO_ShortHashCode),
+				      (char*) result,
+				      sizeof (struct GNUNET_CRYPTO_ShortHashAsciiEncoded) - 1);
+  GNUNET_assert (NULL != np);
+  *np = '\0';
+}
+
+/**
+ * Compare function for ShortHashCodes, producing a total ordering
+ * of all hashcodes.
+ *
+ * @param h1 some hash code
+ * @param h2 some hash code
+ * @return 1 if h1 > h2, -1 if h1 < h2 and 0 if h1 == h2.
+ */
+int
+GNUNET_CRYPTO_short_hash_cmp (const struct GNUNET_CRYPTO_ShortHashCode * h1,
+                        const struct GNUNET_CRYPTO_ShortHashCode * h2)
+{
+  unsigned int *i1;
+  unsigned int *i2;
+  int i;
+
+  i1 = (unsigned int *) h1;
+  i2 = (unsigned int *) h2;
+  for (i = (sizeof (struct GNUNET_CRYPTO_ShortHashCode) / sizeof (unsigned int)) - 1; i >= 0; i--)
+  {
+    if (i1[i] > i2[i])
+      return 1;
+    if (i1[i] < i2[i])
+      return -1;
+  }
+  return 0;
+}
+
 /* end of crypto_hash.c */