cleaning up types used

4 files changed, 134 insertions, 28 deletions

diff --git a/src/include/taler_util.h b/src/include/taler_util.h
index db6f22e68..19e6bacf1 100644
--- a/src/include/taler_util.h
+++ b/src/include/taler_util.h
@@ -241,6 +241,30 @@ TALER_data_to_string_alloc (const void *buf,
 /* ****************** Refresh crypto primitives ************* */
 
 /**
+ * Secret used to decrypt refresh links.
+ */
+struct TALER_LinkSecret
+{
+  /**
+   * Secret used to decrypt the refresh link data.
+   */
+  char key[sizeof (struct GNUNET_HashCode)];
+};
+
+
+/**
+ * Encrypted secret used to decrypt refresh links.
+ */
+struct TALER_EncryptedLinkSecret
+{
+  /**
+   * Encrypted secret, must be the given size!
+   */
+  char enc[sizeof (struct TALER_LinkSecret)];
+};
+
+
+/**
  * Representation of an encrypted refresh link.
  */
 struct TALER_RefreshLinkEncrypted
@@ -295,9 +319,24 @@ struct TALER_RefreshLinkDecrypted
  * @return #GNUNET_OK on success
  */
 int
-TALER_transfer_decrypt (const struct GNUNET_HashCode *secret_enc,
+TALER_transfer_decrypt (const struct TALER_EncryptedLinkSecret *secret_enc,
+                        const struct GNUNET_HashCode *trans_sec,
+                        struct TALER_LinkSecret *secret);
+
+
+/**
+ * Use the @a trans_sec (from ECDHE) to encrypt the @a secret
+ * to obtain the @a secret_enc.
+ *
+ * @param secret shared secret for refresh link decryption
+ * @param trans_sec transfer secret (FIXME: use different type?)
+ * @param secret_enc[out] encrypted secret
+ * @return #GNUNET_OK on success
+ */
+int
+TALER_transfer_encrypt (const struct TALER_LinkSecret *secret,
                         const struct GNUNET_HashCode *trans_sec,
-                        struct GNUNET_HashCode *secret);
+                        struct TALER_EncryptedLinkSecret *secret_enc);
 
 
 /**
@@ -309,7 +348,7 @@ TALER_transfer_decrypt (const struct GNUNET_HashCode *secret_enc,
  */
 struct TALER_RefreshLinkDecrypted *
 TALER_refresh_decrypt (const struct TALER_RefreshLinkEncrypted *input,
-                       const struct GNUNET_HashCode *secret);
+                       const struct TALER_LinkSecret *secret);
 
 
 /**
@@ -321,7 +360,7 @@ TALER_refresh_decrypt (const struct TALER_RefreshLinkEncrypted *input,
  */
 struct TALER_RefreshLinkEncrypted *
 TALER_refresh_encrypt (const struct TALER_RefreshLinkDecrypted *input,
-                       const struct GNUNET_HashCode *secret);
+                       const struct TALER_LinkSecret *secret);
 
 
 #endif
diff --git a/src/mint/mint.h b/src/mint/mint.h
index bf8dfcfd3..046b9c17e 100644
--- a/src/mint/mint.h
+++ b/src/mint/mint.h
@@ -179,10 +179,9 @@ struct RefreshCommitLink
   struct GNUNET_CRYPTO_EcdsaPublicKey transfer_pub;
 
   /**
-   * FIXME: this is the encrypted shared secret, should use
-   * a different type...
+   * Encrypted shared secret to decrypt the link.
    */
-  struct GNUNET_HashCode shared_secret_enc;
+  struct TALER_EncryptedLinkSecret shared_secret_enc;
 };
 
 
diff --git a/src/mint/taler-mint-httpd_db.c b/src/mint/taler-mint-httpd_db.c
index 9ddce104d..8f7553896 100644
--- a/src/mint/taler-mint-httpd_db.c
+++ b/src/mint/taler-mint-httpd_db.c
@@ -908,7 +908,7 @@ TALER_MINT_db_execute_refresh_reveal (struct MHD_Connection *connection,
   off = 0;
   for (i = 0; i < refresh_session.kappa - 1; i++)
   {
-    struct GNUNET_HashCode last_shared_secret;
+    struct TALER_LinkSecret last_shared_secret;
     int secret_initialized = GNUNET_NO;
 
     if (i == refresh_session.noreveal_index)
@@ -919,7 +919,7 @@ TALER_MINT_db_execute_refresh_reveal (struct MHD_Connection *connection,
       struct RefreshCommitLink commit_link;
       struct GNUNET_CRYPTO_EcdsaPublicKey coin_pub;
       struct GNUNET_HashCode transfer_secret;
-      struct GNUNET_HashCode shared_secret;
+      struct TALER_LinkSecret shared_secret;
 
       res = TALER_MINT_DB_get_refresh_commit_link (db_conn,
                                                    refresh_session_pub,
diff --git a/src/util/crypto.c b/src/util/crypto.c
index 930c43a7f..65c586d75 100644
--- a/src/util/crypto.c
+++ b/src/util/crypto.c
@@ -30,24 +30,34 @@
 
 #define CURVE "Ed25519"
 
-
+/**
+ * Function called by libgcrypt on serious errors.
+ * Prints an error message and aborts the process.
+ *
+ * @param cls NULL
+ * @param wtf unknown
+ * @param msg error message
+ */
 static void
-fatal_error_handler (void *cls, int wtf, const char *msg)
+fatal_error_handler (void *cls,
+                     int wtf,
+                     const char *msg)
 {
-  LOG_ERROR("Fatal error in Gcrypt: %s\n", msg);
+  LOG_ERROR ("Fatal error in libgcrypt: %s\n",
+             msg);
   abort();
 }
 
 
 /**
- * Initialize Gcrypt library.
+ * Initialize libgcrypt.
  */
 void
-TALER_gcrypt_init()
+TALER_gcrypt_init ()
 {
   gcry_set_fatalerror_handler (&fatal_error_handler, NULL);
-  TALER_assert_as(gcry_check_version(NEED_LIBGCRYPT_VERSION),
-                  "libgcrypt version mismatch");
+  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);
@@ -56,19 +66,48 @@ TALER_gcrypt_init()
 
 /**
  * Derive symmetric key material for refresh operations from
- * a given shared secret.
+ * a given shared secret for link decryption.
  *
  * @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,
+derive_refresh_key (const struct TALER_LinkSecret *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";
+  static const char ctx_key[] = "taler-link-skey";
+  static const char ctx_iv[] = "taler-link-iv";
+
+  GNUNET_assert (GNUNET_YES ==
+                 GNUNET_CRYPTO_kdf (skey, sizeof (struct GNUNET_CRYPTO_SymmetricSessionKey),
+                                    ctx_key, strlen (ctx_key),
+                                    secret, sizeof (struct TALER_LinkSecret),
+                                    NULL, 0));
+  GNUNET_assert (GNUNET_YES ==
+                 GNUNET_CRYPTO_kdf (iv, sizeof (struct GNUNET_CRYPTO_SymmetricInitializationVector),
+                                    ctx_iv, strlen (ctx_iv),
+                                    secret, sizeof (struct TALER_LinkSecret),
+                                    NULL, 0));
+}
+
+
+/**
+ * Derive symmetric key material for refresh operations from
+ * a given shared secret for key decryption.
+ *
+ * @param secret the shared secret
+ * @param[out] iv set to initialization vector
+ * @param[out] skey set to session key
+ */
+static void
+derive_transfer_key (const struct GNUNET_HashCode *secret,
+                     struct GNUNET_CRYPTO_SymmetricInitializationVector *iv,
+                     struct GNUNET_CRYPTO_SymmetricSessionKey *skey)
+{
+  static const char ctx_key[] = "taler-transfer-skey";
+  static const char ctx_iv[] = "taler-transfer-iv";
 
   GNUNET_assert (GNUNET_YES ==
                  GNUNET_CRYPTO_kdf (skey, sizeof (struct GNUNET_CRYPTO_SymmetricSessionKey),
@@ -87,23 +126,24 @@ derive_refresh_key (const struct GNUNET_HashCode *secret,
  * Use the @a trans_sec (from ECDHE) to decrypt the @a secret_enc
  * to obtain the @a secret to decrypt the linkage data.
  *
- * @param secret_enc encrypted secret (FIXME: use different type!)
+ * @param secret_enc encrypted secret
  * @param trans_sec transfer secret (FIXME: use different type?)
  * @param secret shared secret for refresh link decryption
- *               (FIXME: use different type?)
  * @return #GNUNET_OK on success
  */
 int
-TALER_transfer_decrypt (const struct GNUNET_HashCode *secret_enc,
+TALER_transfer_decrypt (const struct TALER_EncryptedLinkSecret *secret_enc,
                         const struct GNUNET_HashCode *trans_sec,
-                        struct GNUNET_HashCode *secret)
+                        struct TALER_LinkSecret *secret)
 {
   struct GNUNET_CRYPTO_SymmetricInitializationVector iv;
   struct GNUNET_CRYPTO_SymmetricSessionKey skey;
 
-  derive_refresh_key (trans_sec, &iv, &skey);
+  GNUNET_assert (sizeof (struct TALER_EncryptedLinkSecret) ==
+                 sizeof (struct TALER_LinkSecret));
+  derive_transfer_key (trans_sec, &iv, &skey);
   return GNUNET_CRYPTO_symmetric_decrypt (secret_enc,
-                                          sizeof (struct GNUNET_HashCode),
+                                          sizeof (struct TALER_LinkSecret),
                                           &skey,
                                           &iv,
                                           secret);
@@ -111,6 +151,34 @@ TALER_transfer_decrypt (const struct GNUNET_HashCode *secret_enc,
 
 
 /**
+ * Use the @a trans_sec (from ECDHE) to encrypt the @a secret
+ * to obtain the @a secret_enc.
+ *
+ * @param secret shared secret for refresh link decryption
+ * @param trans_sec transfer secret (FIXME: use different type?)
+ * @param secret_enc[out] encrypted secret
+ * @return #GNUNET_OK on success
+ */
+int
+TALER_transfer_encrypt (const struct TALER_LinkSecret *secret,
+                        const struct GNUNET_HashCode *trans_sec,
+                        struct TALER_EncryptedLinkSecret *secret_enc)
+{
+  struct GNUNET_CRYPTO_SymmetricInitializationVector iv;
+  struct GNUNET_CRYPTO_SymmetricSessionKey skey;
+
+  GNUNET_assert (sizeof (struct TALER_EncryptedLinkSecret) ==
+                 sizeof (struct TALER_LinkSecret));
+  derive_transfer_key (trans_sec, &iv, &skey);
+  return GNUNET_CRYPTO_symmetric_encrypt (secret,
+                                          sizeof (struct TALER_LinkSecret),
+                                          &skey,
+                                          &iv,
+                                          secret_enc);
+}
+
+
+/**
  * Decrypt refresh link information.
  *
  * @param input encrypted refresh link data
@@ -119,7 +187,7 @@ TALER_transfer_decrypt (const struct GNUNET_HashCode *secret_enc,
  */
 struct TALER_RefreshLinkDecrypted *
 TALER_refresh_decrypt (const struct TALER_RefreshLinkEncrypted *input,
-                       const struct GNUNET_HashCode *secret)
+                       const struct TALER_LinkSecret *secret)
 {
   struct TALER_RefreshLinkDecrypted *ret;
   struct GNUNET_CRYPTO_SymmetricInitializationVector iv;
@@ -162,7 +230,7 @@ TALER_refresh_decrypt (const struct TALER_RefreshLinkEncrypted *input,
  */
 struct TALER_RefreshLinkEncrypted *
 TALER_refresh_encrypt (const struct TALER_RefreshLinkDecrypted *input,
-                       const struct GNUNET_HashCode *secret)
+                       const struct TALER_LinkSecret *secret)
 {
   char *b_buf;
   size_t b_buf_size;