rework taler lib, moving some code to GNUnet, cleaner refresh encrypt/decypt API

6 files changed, 600 insertions, 470 deletions

diff --git a/src/include/taler_util.h b/src/include/taler_util.h
index d37ac356f..f1264d254 100644
--- a/src/include/taler_util.h
+++ b/src/include/taler_util.h
@@ -65,22 +65,50 @@
   do {int rc; rc = cmd; if (!rc) break; LOG_ERROR("A Gcrypt call failed at %s:%d with error: %s\n", __FILE__, __LINE__, gcry_strerror(rc)); abort(); } while (0)
 
 
+
+/**
+ * Initialize Gcrypt library.
+ */
+void
+TALER_gcrypt_init (void);
+
+
+/* *********************** Amount management ****************** */
+
+
+/**
+ * Number of characters (plus 1 for 0-termination) we use to
+ * represent currency names (i.e. EUR, USD, etc.).
+ */
 #define TALER_CURRENCY_LEN 4
 
 
 GNUNET_NETWORK_STRUCT_BEGIN
 
+/**
+ * Amount, encoded for network transmission.
+ */
 struct TALER_AmountNBO
 {
+  /**
+   * Value in the main currency, in NBO.
+   */
   uint32_t value;
+
+  /**
+   * Additinal fractional value, in NBO.
+   */
   uint32_t fraction;
+
+  /**
+   * Type of the currency being represented.
+   */
   char currency[TALER_CURRENCY_LEN];
 };
 
 GNUNET_NETWORK_STRUCT_END
 
 
-
 /**
  * Representation of monetary value in a given currency.
  */
@@ -90,10 +118,12 @@ struct TALER_Amount
    * Value (numerator of fraction)
    */
   uint32_t value;
+
   /**
    * Fraction (denominator of fraction)
    */
   uint32_t fraction;
+
   /**
    * Currency string, left adjusted and padded with zeros.
    */
@@ -102,37 +132,38 @@ struct TALER_Amount
 
 
 /**
- * Initialize Gcrypt library.
- */
-void
-TALER_gcrypt_init (void);
-
-
-/**
  * Parse denomination description, in the format "T : V : F".
  *
  * @param str denomination description
  * @param denom denomination to write the result to
- * @return GNUNET_OK if the string is a valid denomination specification,
- *         GNUNET_SYSERR if it is invalid.
+ * @return #GNUNET_OK if the string is a valid denomination specification,
+ *         #GNUNET_SYSERR if it is invalid.
  */
 int
-TALER_string_to_amount (const char *str, struct TALER_Amount *denom);
+TALER_string_to_amount (const char *str,
+                        struct TALER_Amount *denom);
 
 
 /**
- * FIXME
+ * Convert amount from host to network representation.
+ *
+ * @param d amount in host representation
+ * @return amount in network representation
  */
 struct TALER_AmountNBO
 TALER_amount_hton (struct TALER_Amount d);
 
 
 /**
- * FIXME
+ * Convert amount from network to host representation.
+ *
+ * @param d amount in network representation
+ * @return amount in host representation
  */
 struct TALER_Amount
 TALER_amount_ntoh (struct TALER_AmountNBO dn);
 
+
 /**
  * Compare the value/fraction of two amounts.  Does not compare the currency,
  * i.e. comparing amounts with the same value and fraction but different
@@ -143,7 +174,8 @@ TALER_amount_ntoh (struct TALER_AmountNBO dn);
  * @return result of the comparison
  */
 int
-TALER_amount_cmp (struct TALER_Amount a1, struct TALER_Amount a2);
+TALER_amount_cmp (struct TALER_Amount a1,
+                  struct TALER_Amount a2);
 
 
 /**
@@ -154,7 +186,8 @@ TALER_amount_cmp (struct TALER_Amount a1, struct TALER_Amount a2);
  * @return (a1-a2) or 0 if a2>=a1
  */
 struct TALER_Amount
-TALER_amount_subtract (struct TALER_Amount a1, struct TALER_Amount a2);
+TALER_amount_subtract (struct TALER_Amount a1,
+                       struct TALER_Amount a2);
 
 
 /**
@@ -165,7 +198,8 @@ TALER_amount_subtract (struct TALER_Amount a1, struct TALER_Amount a2);
  * @return sum of a1 and a2
  */
 struct TALER_Amount
-TALER_amount_add (struct TALER_Amount a1, struct TALER_Amount a2);
+TALER_amount_add (struct TALER_Amount a1,
+                  struct TALER_Amount a2);
 
 
 /**
@@ -187,43 +221,89 @@ TALER_amount_normalize (struct TALER_Amount amount);
 char *
 TALER_amount_to_string (struct TALER_Amount amount);
 
+/* ****************** FIXME: move to GNUnet? ************** */
 
 /**
  * Return the base32crockford encoding of the given buffer.
  *
  * The returned string will be freshly allocated, and must be free'd
- * with GNUNET_free.
+ * with #GNUNET_free().
  *
  * @param buffer with data
  * @param size size of the buffer
  * @return freshly allocated, null-terminated string
  */
 char *
-TALER_data_to_string_alloc (const void *buf, size_t size);
+TALER_data_to_string_alloc (const void *buf,
+                            size_t size);
+
 
+/* ****************** Refresh crypto primitives ************* */
 
 /**
- * Get encoded binary data from a configuration.
- *
- * @return GNUNET_OK on success
- *         GNUNET_NO is the value does not exist
- *         GNUNET_SYSERR on encoding error
+ * Representation of an encrypted refresh link.
  */
-int
-TALER_configuration_get_data (const struct GNUNET_CONFIGURATION_Handle *cfg,
-                              const char *section, const char *option,
-                              void *buf, size_t buf_size);
+struct TALER_RefreshLinkEncrypted
+{
 
+  /**
+   * Encrypted private key of the coin.
+   */
+  char [sizeof (struct GNUNET_CRYPTO_EcdsaPrivateKey)] coin_priv_enc;
 
+  /**
+   * Encrypted blinding key with @e blinding_key_enc_size bytes.
+   */
+  char *blinding_key_enc;
 
+  /**
+   * Number of bytes in @e blinding_key_enc.
+   */
+  size_t blinding_key_enc_size;
+};
 
-int
-TALER_refresh_decrypt (const void *input, size_t input_size, const struct GNUNET_HashCode *secret, void *result);
 
-int
-TALER_refresh_encrypt (const void *input, size_t input_size, const struct GNUNET_HashCode *secret, void *result);
+/**
+ * Representation of an refresh link in cleartext.
+ */
+struct TALER_RefreshLinkDecrypted
+{
+
+  /**
+   * Private key of the coin.
+   */
+  struct GNUNET_CRYPTO_EcdsaPrivateKey coin_priv;
+
+  /**
+   * Blinding key with @e blinding_key_enc_size bytes.
+   */
+  struct GNUNET_CRYPTO_rsa_BlindingKey *blinding_key;
+
+};
 
 
+/**
+ * Decrypt refresh link information.
+ *
+ * @param input encrypted refresh link data
+ * @param secret shared secret to use for decryption
+ * @return NULL on error
+ */
+struct TALER_RefreshLinkDecrypted *
+TALER_refresh_decrypt (const struct TALER_RefreshLinkEncrypted *input,
+                       const struct GNUNET_HashCode *secret);
+
+
+/**
+ * Encrypt refresh link information.
+ *
+ * @param input plaintext refresh link data
+ * @param secret shared secret to use for encryption
+ * @return NULL on error (should never happen)
+ */
+struct TALER_RefreshLinkEncrypted *
+TALER_refresh_encrypt (const struct TALER_RefreshLinkDecrypted *input,
+                       const struct GNUNET_HashCode *secret);
 
 
 #endif
diff --git a/src/mint/mint.h b/src/mint/mint.h
index 3f98b368d..b194be687 100644
--- a/src/mint/mint.h
+++ b/src/mint/mint.h
@@ -117,9 +117,9 @@ struct CollectableBlindcoin
 
 struct RefreshSession
 {
-  int has_commit_sig;
   struct GNUNET_CRYPTO_EddsaSignature commit_sig;
   struct GNUNET_CRYPTO_EddsaPublicKey session_pub;
+  int has_commit_sig;
   uint16_t num_oldcoins;
   uint16_t num_newcoins;
   uint16_t kappa;
@@ -128,46 +128,33 @@ struct RefreshSession
 };
 
 
-#define TALER_REFRESH_SHARED_SECRET_LENGTH (sizeof (struct GNUNET_HashCode))
-#define TALER_REFRESH_LINK_LENGTH (sizeof (struct LinkData))
-
+/**
+ * FIXME
+ */
 struct RefreshCommitLink
 {
   struct GNUNET_CRYPTO_EddsaPublicKey session_pub;
   struct GNUNET_CRYPTO_EcdsaPublicKey transfer_pub;
+  struct GNUNET_HashCode shared_secret;
   uint16_t cnc_index;
   uint16_t oldcoin_index;
-  char shared_secret_enc[sizeof (struct GNUNET_HashCode)];
-};
-
-struct LinkData
-{
-  struct GNUNET_CRYPTO_EcdsaPrivateKey coin_priv;
-  struct GNUNET_CRYPTO_rsa_BlindingKey *bkey_enc;
 };
 
 
-GNUNET_NETWORK_STRUCT_BEGIN
-
-struct SharedSecretEnc
-{
-  char data[TALER_REFRESH_SHARED_SECRET_LENGTH];
-};
-
-
-struct LinkDataEnc
-{
-  char data[sizeof (struct LinkData)];
-};
-
-GNUNET_NETWORK_STRUCT_END
-
+/**
+ * FIXME
+ */
 struct RefreshCommitCoin
 {
+  /**
+   * Refresh session's public key.
+   */
   struct GNUNET_CRYPTO_EddsaPublicKey session_pub;
 
+  struct TALER_RefreshLinkEncrypted refresh_link;
+
   /**
-   * Blinded message to be signed (in envelope).
+   * Blinded message to be signed (in envelope), with @e coin_env_size bytes.
    */
   char *coin_ev;
 
@@ -176,22 +163,36 @@ struct RefreshCommitCoin
    */
   size_t coin_ev_size;
 
+  /**
+   * FIXME: needed?
+   */
   uint16_t cnc_index;
+
+  /**
+   * FIXME: needed?
+   */
   uint16_t newcoin_index;
-  char link_enc[sizeof (struct LinkData)];
+
 };
 
 
+/**
+ * FIXME
+ */
 struct KnownCoin
 {
   struct TALER_CoinPublicInfo public_info;
-  struct TALER_Amount expended_balance;
-  int is_refreshed;
+
   /**
    * Refreshing session, only valid if
    * is_refreshed==1.
    */
   struct GNUNET_CRYPTO_EddsaPublicKey refresh_session_pub;
+
+  struct TALER_Amount expended_balance;
+
+  int is_refreshed;
+
 };
 
 
@@ -356,11 +357,15 @@ TALER_MINT_config_load (const char *mint_base_dir);
 
 
 int
-TALER_TALER_DB_extract_amount (PGresult *result, unsigned int row,
-                        int indices[3], struct TALER_Amount *denom);
+TALER_TALER_DB_extract_amount (PGresult *result,
+                               unsigned int row,
+                               int indices[3],
+                               struct TALER_Amount *denom);
 
 int
-TALER_TALER_DB_extract_amount_nbo (PGresult *result, unsigned int row,
-                             int indices[3], struct TALER_AmountNBO *denom_nbo);
+TALER_TALER_DB_extract_amount_nbo (PGresult *result,
+                                   unsigned int row,
+                                   int indices[3],
+                                   struct TALER_AmountNBO *denom_nbo);
 
 #endif /* _MINT_H */
diff --git a/src/util/Makefile.am b/src/util/Makefile.am
index 2fbcb54b4..bb07e2ca3 100644
--- a/src/util/Makefile.am
+++ b/src/util/Makefile.am
@@ -4,6 +4,8 @@ lib_LTLIBRARIES = \
   libtalerutil.la
 
 libtalerutil_la_SOURCES = \
+  amount.c \
+  crypto.c \
   util.c \
   json.c \
   db.c
diff --git a/src/util/amount.c b/src/util/amount.c
new file mode 100644
index 000000000..8bd899bf5
--- /dev/null
+++ b/src/util/amount.c
@@ -0,0 +1,329 @@
+/*
+  This file is part of TALER
+  (C) 2014 Christian Grothoff (and other contributing authors)
+
+  TALER 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 3, or (at your option) any later version.
+
+  TALER 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
+  TALER; see the file COPYING.  If not, If not, see <http://www.gnu.org/licenses/>
+*/
+
+/**
+ * @file amount.c
+ * @brief Common utility functions to deal with units of currency
+ * @author Sree Harsha Totakura <sreeharsha@totakura.in>
+ * @author Florian Dold
+ * @author Benedikt Mueller
+ */
+#include "platform.h"
+#include "taler_util.h"
+#include <gnunet/gnunet_common.h>
+#include <gnunet/gnunet_util_lib.h>
+#include <gcrypt.h>
+
+#define AMOUNT_FRAC_BASE 1000000
+
+#define AMOUNT_FRAC_LEN 6
+
+
+/**
+ * Parse money amount description, in the format "A:B.C".
+ *
+ * @param str amount description
+ * @param denom amount to write the result to
+ * @return #GNUNET_OK if the string is a valid amount specification,
+ *         #GNUNET_SYSERR if it is invalid.
+ */
+int
+TALER_string_to_amount (const char *str,
+                        struct TALER_Amount *denom)
+{
+  unsigned int i; // pos in str
+  int n; // number tmp
+  unsigned int c; // currency pos
+  uint32_t b; // base for suffix
+
+  memset (denom, 0, sizeof (struct TALER_Amount));
+
+  i = n = c = 0;
+
+  while (isspace(str[i]))
+    i++;
+
+  if (0 == str[i])
+  {
+    printf("null before currency\n");
+    return GNUNET_SYSERR;
+  }
+
+  while (str[i] != ':')
+  {
+    if (0 == str[i])
+    {
+      printf("null before colon");
+      return GNUNET_SYSERR;
+    }
+    if (c > 3)
+    {
+      printf("currency too long\n");
+      return GNUNET_SYSERR;
+    }
+    denom->currency[c] = str[i];
+    c++;
+    i++;
+  }
+
+  // skip colon
+  i++;
+
+  if (0 == str[i])
+  {
+    printf("null before value\n");
+    return GNUNET_SYSERR;
+  }
+
+  while (str[i] != '.')
+  {
+    if (0 == str[i])
+    {
+      return GNUNET_OK;
+    }
+    n = str[i] - '0';
+    if (n < 0 || n > 9)
+    {
+      printf("invalid character '%c' before comma at %u\n", (char) n, i);
+      return GNUNET_SYSERR;
+    }
+    denom->value = (denom->value * 10) + n;
+    i++;
+  }
+
+  // skip the dot
+  i++;
+
+  if (0 == str[i])
+  {
+    printf("null after dot");
+    return GNUNET_SYSERR;
+  }
+
+  b = 100000;
+
+  while (0 != str[i])
+  {
+    n = str[i] - '0';
+    if (b == 0 || n < 0 || n > 9)
+    {
+      printf("error after comma");
+      return GNUNET_SYSERR;
+    }
+    denom->fraction += n * b;
+    b /= 10;
+    i++;
+  }
+
+  return GNUNET_OK;
+}
+
+
+/**
+ * FIXME
+ */
+struct TALER_AmountNBO
+TALER_amount_hton (struct TALER_Amount d)
+{
+  struct TALER_AmountNBO dn;
+  dn.value = htonl (d.value);
+  dn.fraction = htonl (d.fraction);
+  memcpy (dn.currency, d.currency, TALER_CURRENCY_LEN);
+
+  return dn;
+}
+
+
+/**
+ * FIXME
+ */
+struct TALER_Amount
+TALER_amount_ntoh (struct TALER_AmountNBO dn)
+{
+  struct TALER_Amount d;
+  d.value = ntohl (dn.value);
+  d.fraction = ntohl (dn.fraction);
+  memcpy (d.currency, dn.currency, sizeof(dn.currency));
+
+  return d;
+}
+
+
+/**
+ * Compare the value/fraction of two amounts.  Does not compare the currency,
+ * i.e. comparing amounts with the same value and fraction but different
+ * currency would return 0.
+ *
+ * @param a1 first amount
+ * @param a2 second amount
+ * @return result of the comparison
+ */
+int
+TALER_amount_cmp (struct TALER_Amount a1, struct TALER_Amount a2)
+{
+  a1 = TALER_amount_normalize (a1);
+  a2 = TALER_amount_normalize (a2);
+  if (a1.value == a2.value)
+  {
+    if (a1.fraction < a2.fraction)
+      return -1;
+    if (a1.fraction > a2.fraction)
+      return 1;
+    return 0;
+  }
+  if (a1.value < a2.value)
+    return -1;
+  return 1;
+}
+
+
+/**
+ * Perform saturating subtraction of amounts.
+ *
+ * @param a1 amount to subtract from
+ * @param a2 amount to subtract
+ * @return (a1-a2) or 0 if a2>=a1
+ */
+struct TALER_Amount
+TALER_amount_subtract (struct TALER_Amount a1, struct TALER_Amount a2)
+{
+  a1 = TALER_amount_normalize (a1);
+  a2 = TALER_amount_normalize (a2);
+
+  if (a1.value < a2.value)
+  {
+    a1.value = 0;
+    a1.fraction = 0;
+    return a1;
+  }
+
+  if (a1.fraction < a2.fraction)
+  {
+    if (0 == a1.value)
+    {
+      a1.fraction = 0;
+      return a1;
+    }
+    a1.fraction += AMOUNT_FRAC_BASE;
+    a1.value -= 1;
+  }
+
+  a1.fraction -= a2.fraction;
+  a1.value -= a2.value;
+
+  return a1;
+}
+
+
+/**
+ * Perform saturating addition of amounts.
+ *
+ * @param a1 first amount to add
+ * @param a2 second amount to add
+ * @return sum of a1 and a2
+ */
+struct TALER_Amount
+TALER_amount_add (struct TALER_Amount a1, struct TALER_Amount a2)
+{
+  a1 = TALER_amount_normalize (a1);
+  a2 = TALER_amount_normalize (a2);
+
+  a1.value += a2.value;
+  a1.fraction += a2.fraction;
+
+  if (0 == a1.currency[0])
+  {
+    memcpy (a2.currency, a1.currency, TALER_CURRENCY_LEN);
+  }
+
+  if (0 == a2.currency[0])
+  {
+    memcpy (a1.currency, a2.currency, TALER_CURRENCY_LEN);
+  }
+
+  if (0 != a1.currency[0] && 0 != memcmp (a1.currency, a2.currency, TALER_CURRENCY_LEN))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "adding mismatching currencies\n");
+  }
+
+  if (a1.value < a2.value)
+  {
+    a1.value = UINT32_MAX;
+    a2.value = UINT32_MAX;
+    return a1;
+  }
+
+  return TALER_amount_normalize (a1);
+}
+
+
+/**
+ * Normalize the given amount.
+ *
+ * @param amout amount to normalize
+ * @return normalized amount
+ */
+struct TALER_Amount
+TALER_amount_normalize (struct TALER_Amount amount)
+{
+  while (amount.value != UINT32_MAX && amount.fraction >= AMOUNT_FRAC_BASE)
+  {
+    amount.fraction -= AMOUNT_FRAC_BASE;
+    amount.value += 1;
+  }
+  return amount;
+}
+
+
+/**
+ * Convert amount to string.
+ *
+ * @param amount amount to convert to string
+ * @return freshly allocated string representation
+ */
+char *
+TALER_amount_to_string (struct TALER_Amount amount)
+{
+  char tail[AMOUNT_FRAC_LEN + 1] = { 0 };
+  char curr[TALER_CURRENCY_LEN + 1] = { 0 };
+  char *result = NULL;
+  int len;
+
+  memcpy (curr, amount.currency, TALER_CURRENCY_LEN);
+
+  amount = TALER_amount_normalize (amount);
+  if (0 != amount.fraction)
+  {
+    unsigned int i;
+    uint32_t n = amount.fraction;
+    for (i = 0; (i < AMOUNT_FRAC_LEN) && (n != 0); i++)
+    {
+      tail[i] = '0' + (n / (AMOUNT_FRAC_BASE / 10));
+      n = (n * 10) % (AMOUNT_FRAC_BASE);
+    }
+    tail[i] = 0;
+    len = GNUNET_asprintf (&result, "%s:%lu.%s", curr, (unsigned long) amount.value, tail);
+  }
+  else
+  {
+    len = GNUNET_asprintf (&result, "%s:%lu", curr, (unsigned long) amount.value);
+  }
+  GNUNET_assert (len > 0);
+  return result;
+}
+
+
+/* end of amount.c */
diff --git a/src/util/crypto.c b/src/util/crypto.c
new file mode 100644
index 000000000..7ff741159
--- /dev/null
+++ b/src/util/crypto.c
@@ -0,0 +1,118 @@
+/*
+  This file is part of TALER
+  (C) 2014 Christian Grothoff (and other contributing authors)
+
+  TALER 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 3, or (at your option) any later version.
+
+  TALER 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
+  TALER; see the file COPYING.  If not, If not, see <http://www.gnu.org/licenses/>
+*/
+
+/**
+ * @file crypto.c
+ * @brief Cryptographic utility functions
+ * @author Sree Harsha Totakura <sreeharsha@totakura.in>
+ * @author Florian Dold
+ * @author Benedikt Mueller
+ */
+
+#include "platform.h"
+#include "taler_util.h"
+#include <gnunet/gnunet_common.h>
+#include <gnunet/gnunet_util_lib.h>
+#include <gcrypt.h>
+
+#define CURVE "Ed25519"
+
+
+static void
+fatal_error_handler (void *cls, int wtf, const char *msg)
+{
+  LOG_ERROR("Fatal error in Gcrypt: %s\n", msg);
+  abort();
+}
+
+
+/**
+ * Initialize Gcrypt library.
+ */
+void
+TALER_gcrypt_init()
+{
+  gcry_set_fatalerror_handler (&fatal_error_handler, NULL);
+  TALER_assert_as(gcry_check_version(NEED_LIBGCRYPT_VERSION),
+                  "libgcrypt version mismatch");
+  /* Disable secure memory.  */
+  gcry_control (GCRYCTL_DISABLE_SECMEM, 0);
+  gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
+}
+
+
+/**
+ * Derive symmetric key material for refresh operations from
+ * a given shared secret.
+ *
+ * @param secret the shared secret
+ * @param[out] iv set to initialization vector
+ * @param[out] skey set to session key
+ */
+static void
+derive_refresh_key (const struct GNUNET_HashCode *secret,
+                    struct GNUNET_CRYPTO_SymmetricInitializationVector *iv,
+                    struct GNUNET_CRYPTO_SymmetricSessionKey *skey)
+{
+  static const char ctx_key[] = "taler-key-skey";
+  static const char ctx_iv[] = "taler-key-iv";
+
+  GNUNET_assert (GNUNET_YES ==
+                 GNUNET_CRYPTO_kdf (skey, sizeof (struct GNUNET_CRYPTO_SymmetricSessionKey),
+                                    ctx_key, strlen (ctx_key),
+                                    secret, sizeof (struct GNUNET_HashCode),
+                                    NULL, 0));
+  GNUNET_assert (GNUNET_YES ==
+                 GNUNET_CRYPTO_kdf (iv, sizeof (struct GNUNET_CRYPTO_SymmetricInitializationVector),
+                                    ctx_iv, strlen (ctx_iv),
+                                    secret, sizeof (struct GNUNET_HashCode),
+                                    NULL, 0));
+}
+
+
+int
+TALER_refresh_decrypt (const void *input,
+                       size_t input_size,
+                       const struct GNUNET_HashCode *secret,
+                       void *result)
+{
+  struct GNUNET_CRYPTO_SymmetricInitializationVector iv;
+  struct GNUNET_CRYPTO_SymmetricSessionKey skey;
+
+  derive_refresh_key (secret, &iv, &skey);
+
+  return GNUNET_CRYPTO_symmetric_decrypt (input, input_size, &skey, &iv, result);
+}
+
+
+int
+TALER_refresh_encrypt (const void *input,
+                       size_t input_size,
+                       const struct GNUNET_HashCode *secret,
+                       void *result)
+{
+  struct GNUNET_CRYPTO_SymmetricInitializationVector iv;
+  struct GNUNET_CRYPTO_SymmetricSessionKey skey;
+
+  derive_refresh_key (secret, &iv, &skey);
+
+  return GNUNET_CRYPTO_symmetric_encrypt (input, input_size, &skey, &iv, result);
+}
+
+
+
+
+/* end of crypto.c */
diff --git a/src/util/util.c b/src/util/util.c
index 80f8fc5f0..440b49fab 100644
--- a/src/util/util.c
+++ b/src/util/util.c
@@ -28,335 +28,11 @@
 #include <gnunet/gnunet_util_lib.h>
 #include <gcrypt.h>
 
-#define CURVE "Ed25519"
-
-#define AMOUNT_FRAC_BASE 1000000
-#define AMOUNT_FRAC_LEN 6
-
-
-
-static void
-fatal_error_handler (void *cls, int wtf, const char *msg)
-{
-  LOG_ERROR("Fatal error in Gcrypt: %s\n", msg);
-  abort();
-}
-
-
-/**
- * Initialize Gcrypt library.
- */
-void
-TALER_gcrypt_init()
-{
-  gcry_set_fatalerror_handler (&fatal_error_handler, NULL);
-  TALER_assert_as(gcry_check_version(NEED_LIBGCRYPT_VERSION),
-                  "libgcrypt version mismatch");
-  /* Disable secure memory.  */
-  gcry_control (GCRYCTL_DISABLE_SECMEM, 0);
-  gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
-}
-
-
-/**
- * Parse money amount description, in the format "A:B.C".
- *
- * @param str amount description
- * @param denom amount to write the result to
- * @return GNUNET_OK if the string is a valid amount specification,
- *         GNUNET_SYSERR if it is invalid.
- */
-int
-TALER_string_to_amount (const char *str, struct TALER_Amount *denom)
-{
-  unsigned int i; // pos in str
-  int n; // number tmp
-  unsigned int c; // currency pos
-  uint32_t b; // base for suffix
-
-  memset (denom, 0, sizeof (struct TALER_Amount));
-
-  i = n = c = 0;
-
-  while (isspace(str[i]))
-    i++;
-
-  if (0 == str[i])
-  {
-    printf("null before currency\n");
-    return GNUNET_SYSERR;
-  }
-
-  while (str[i] != ':')
-  {
-    if (0 == str[i])
-    {
-      printf("null before colon");
-      return GNUNET_SYSERR;
-    }
-    if (c > 3)
-    {
-      printf("currency too long\n");
-      return GNUNET_SYSERR;
-    }
-    denom->currency[c] = str[i];
-    c++;
-    i++;
-  }
-
-  // skip colon
-  i++;
-
-  if (0 == str[i])
-  {
-    printf("null before value\n");
-    return GNUNET_SYSERR;
-  }
-
-  while (str[i] != '.')
-  {
-    if (0 == str[i])
-    {
-      return GNUNET_OK;
-    }
-    n = str[i] - '0';
-    if (n < 0 || n > 9)
-    {
-      printf("invalid character '%c' before comma at %u\n", (char) n, i);
-      return GNUNET_SYSERR;
-    }
-    denom->value = (denom->value * 10) + n;
-    i++;
-  }
-
-  // skip the dot
-  i++;
-
-  if (0 == str[i])
-  {
-    printf("null after dot");
-    return GNUNET_SYSERR;
-  }
-
-  b = 100000;
-
-  while (0 != str[i])
-  {
-    n = str[i] - '0';
-    if (b == 0 || n < 0 || n > 9)
-    {
-      printf("error after comma");
-      return GNUNET_SYSERR;
-    }
-    denom->fraction += n * b;
-    b /= 10;
-    i++;
-  }
-
-  return GNUNET_OK;
-}
-
-
-/**
- * FIXME
- */
-struct TALER_AmountNBO
-TALER_amount_hton (struct TALER_Amount d)
-{
-  struct TALER_AmountNBO dn;
-  dn.value = htonl (d.value);
-  dn.fraction = htonl (d.fraction);
-  memcpy (dn.currency, d.currency, TALER_CURRENCY_LEN);
-
-  return dn;
-}
-
-
-/**
- * FIXME
- */
-struct TALER_Amount
-TALER_amount_ntoh (struct TALER_AmountNBO dn)
-{
-  struct TALER_Amount d;
-  d.value = ntohl (dn.value);
-  d.fraction = ntohl (dn.fraction);
-  memcpy (d.currency, dn.currency, sizeof(dn.currency));
-
-  return d;
-}
-
-
-/**
- * Compare the value/fraction of two amounts.  Does not compare the currency,
- * i.e. comparing amounts with the same value and fraction but different
- * currency would return 0.
- *
- * @param a1 first amount
- * @param a2 second amount
- * @return result of the comparison
- */
-int
-TALER_amount_cmp (struct TALER_Amount a1, struct TALER_Amount a2)
-{
-  a1 = TALER_amount_normalize (a1);
-  a2 = TALER_amount_normalize (a2);
-  if (a1.value == a2.value)
-  {
-    if (a1.fraction < a2.fraction)
-      return -1;
-    if (a1.fraction > a2.fraction)
-      return 1;
-    return 0;
-  }
-  if (a1.value < a2.value)
-    return -1;
-  return 1;
-}
-
-
-/**
- * Perform saturating subtraction of amounts.
- *
- * @param a1 amount to subtract from
- * @param a2 amount to subtract
- * @return (a1-a2) or 0 if a2>=a1
- */
-struct TALER_Amount
-TALER_amount_subtract (struct TALER_Amount a1, struct TALER_Amount a2)
-{
-  a1 = TALER_amount_normalize (a1);
-  a2 = TALER_amount_normalize (a2);
-
-  if (a1.value < a2.value)
-  {
-    a1.value = 0;
-    a1.fraction = 0;
-    return a1;
-  }
-
-  if (a1.fraction < a2.fraction)
-  {
-    if (0 == a1.value)
-    {
-      a1.fraction = 0;
-      return a1;
-    }
-    a1.fraction += AMOUNT_FRAC_BASE;
-    a1.value -= 1;
-  }
-
-  a1.fraction -= a2.fraction;
-  a1.value -= a2.value;
-
-  return a1;
-}
-
-
-/**
- * Perform saturating addition of amounts.
- *
- * @param a1 first amount to add
- * @param a2 second amount to add
- * @return sum of a1 and a2
- */
-struct TALER_Amount
-TALER_amount_add (struct TALER_Amount a1, struct TALER_Amount a2)
-{
-  a1 = TALER_amount_normalize (a1);
-  a2 = TALER_amount_normalize (a2);
-
-  a1.value += a2.value;
-  a1.fraction += a2.fraction;
-
-  if (0 == a1.currency[0])
-  {
-    memcpy (a2.currency, a1.currency, TALER_CURRENCY_LEN);
-  }
-
-  if (0 == a2.currency[0])
-  {
-    memcpy (a1.currency, a2.currency, TALER_CURRENCY_LEN);
-  }
-
-  if (0 != a1.currency[0] && 0 != memcmp (a1.currency, a2.currency, TALER_CURRENCY_LEN))
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "adding mismatching currencies\n");
-  }
-
-  if (a1.value < a2.value)
-  {
-    a1.value = UINT32_MAX;
-    a2.value = UINT32_MAX;
-    return a1;
-  }
-
-  return TALER_amount_normalize (a1);
-}
-
-
-/**
- * Normalize the given amount.
- *
- * @param amout amount to normalize
- * @return normalized amount
- */
-struct TALER_Amount
-TALER_amount_normalize (struct TALER_Amount amount)
-{
-  while (amount.value != UINT32_MAX && amount.fraction >= AMOUNT_FRAC_BASE)
-  {
-    amount.fraction -= AMOUNT_FRAC_BASE;
-    amount.value += 1;
-  }
-  return amount;
-}
-
-
-/**
- * Convert amount to string.
- *
- * @param amount amount to convert to string
- * @return freshly allocated string representation
- */
-char *
-TALER_amount_to_string (struct TALER_Amount amount)
-{
-  char tail[AMOUNT_FRAC_LEN + 1] = { 0 };
-  char curr[TALER_CURRENCY_LEN + 1] = { 0 };
-  char *result = NULL;
-  int len;
-
-  memcpy (curr, amount.currency, TALER_CURRENCY_LEN);
-
-  amount = TALER_amount_normalize (amount);
-  if (0 != amount.fraction)
-  {
-    unsigned int i;
-    uint32_t n = amount.fraction;
-    for (i = 0; (i < AMOUNT_FRAC_LEN) && (n != 0); i++)
-    {
-      tail[i] = '0' + (n / (AMOUNT_FRAC_BASE / 10));
-      n = (n * 10) % (AMOUNT_FRAC_BASE);
-    }
-    tail[i] = 0;
-    len = GNUNET_asprintf (&result, "%s:%lu.%s", curr, (unsigned long) amount.value, tail);
-  }
-  else
-  {
-    len = GNUNET_asprintf (&result, "%s:%lu", curr, (unsigned long) amount.value);
-  }
-  GNUNET_assert (len > 0);
-  return result;
-}
-
-
-
 /**
  * Return the base32crockford encoding of the given buffer.
  *
  * The returned string will be freshly allocated, and must be free'd
- * with GNUNET_free.
+ * with GNUNET_free().
  *
  * @param buffer with data
  * @param size size of the buffer
@@ -384,84 +60,4 @@ TALER_data_to_string_alloc (const void *buf, size_t size)
 }
 
 
-/**
- * Get encoded binary data from a configuration.
- *
- * @return GNUNET_OK on success
- *         GNUNET_NO is the value does not exist
- *         GNUNET_SYSERR on encoding error
- */
-int
-TALER_configuration_get_data (const struct GNUNET_CONFIGURATION_Handle *cfg,
-                              const char *section, const char *option,
-                              void *buf, size_t buf_size)
-{
-  char *enc;
-  int res;
-  size_t data_size;
-  if (GNUNET_OK != (res = GNUNET_CONFIGURATION_get_value_string (cfg, section, option, &enc)))
-    return res;
-  data_size = (strlen (enc) * 5) / 8;
-  if (data_size != buf_size)
-  {
-    GNUNET_free (enc);
-    return GNUNET_SYSERR;
-  }
-  if (GNUNET_OK != GNUNET_STRINGS_string_to_data (enc, strlen (enc),
-                                                  buf, buf_size))
-  {
-    GNUNET_free (enc);
-    return GNUNET_SYSERR;
-  }
-  return GNUNET_OK;
-}
-
-
-static void
-derive_refresh_key (const struct GNUNET_HashCode *secret,
-                    struct GNUNET_CRYPTO_SymmetricInitializationVector *iv,
-                    struct GNUNET_CRYPTO_SymmetricSessionKey *skey)
-{
-  static const char ctx_key[] = "taler-key-skey";
-  static const char ctx_iv[] = "taler-key-iv";
-
-  GNUNET_assert (GNUNET_YES ==
-                 GNUNET_CRYPTO_kdf (skey, sizeof (struct GNUNET_CRYPTO_SymmetricSessionKey),
-                                    ctx_key, strlen (ctx_key),
-                                    secret, sizeof (struct GNUNET_HashCode),
-                                    NULL, 0));
-  GNUNET_assert (GNUNET_YES ==
-                 GNUNET_CRYPTO_kdf (iv, sizeof (struct GNUNET_CRYPTO_SymmetricInitializationVector),
-                                    ctx_iv, strlen (ctx_iv),
-                                    secret, sizeof (struct GNUNET_HashCode),
-                                    NULL, 0));
-}
-
-
-int
-TALER_refresh_decrypt (const void *input, size_t input_size, const struct GNUNET_HashCode *secret, void *result)
-{
-  struct GNUNET_CRYPTO_SymmetricInitializationVector iv;
-  struct GNUNET_CRYPTO_SymmetricSessionKey skey;
-
-  derive_refresh_key (secret, &iv, &skey);
-
-  return GNUNET_CRYPTO_symmetric_decrypt (input, input_size, &skey, &iv, result);
-}
-
-
-int
-TALER_refresh_encrypt (const void *input, size_t input_size, const struct GNUNET_HashCode *secret, void *result)
-{
-  struct GNUNET_CRYPTO_SymmetricInitializationVector iv;
-  struct GNUNET_CRYPTO_SymmetricSessionKey skey;
-
-  derive_refresh_key (secret, &iv, &skey);
-
-  return GNUNET_CRYPTO_symmetric_encrypt (input, input_size, &skey, &iv, result);
-}
-
-
-
-
 /* end of util.c */