1 files changed, 148 insertions, 0 deletions

diff --git a/src/util/crypto_aes.c b/src/util/crypto_aes.c
new file mode 100644
index 000000000..28a65dfca
--- /dev/null
+++ b/src/util/crypto_aes.c
@@ -0,0 +1,148 @@
+/*
+     This file is part of GNUnet.
+     (C) 2001, 2002, 2003, 2004, 2005, 2006 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.
+*/
+
+/**
+ * @file util/crypto_aes.c
+ * @brief Symmetric encryption services.
+ * @author Christian Grothoff
+ * @author Ioana Patrascu
+ */
+
+#include "platform.h"
+#include "gnunet_common.h"
+#include "gnunet_crypto_lib.h"
+#include <gcrypt.h>
+
+/**
+ * Create a new SessionKey (for AES-256).
+ */
+void
+GNUNET_CRYPTO_aes_create_session_key (struct GNUNET_CRYPTO_AesSessionKey *key)
+{
+  gcry_randomize (&key->key[0], GNUNET_CRYPTO_AES_KEY_LENGTH,
+                  GCRY_STRONG_RANDOM);
+  key->crc32 =
+    htonl (GNUNET_CRYPTO_crc32_n (key, GNUNET_CRYPTO_AES_KEY_LENGTH));
+}
+
+/**
+ * Check that a new session key is well-formed.
+ *
+ * @return GNUNET_OK if the key is valid
+ */
+int
+GNUNET_CRYPTO_aes_check_session_key (const struct GNUNET_CRYPTO_AesSessionKey
+                                     *key)
+{
+  uint32_t crc;
+
+  crc = GNUNET_CRYPTO_crc32_n (key, GNUNET_CRYPTO_AES_KEY_LENGTH);
+  if (ntohl (key->crc32) == crc)
+    return GNUNET_OK;
+  GNUNET_break (0);
+  return GNUNET_SYSERR;
+}
+
+
+/**
+ * Encrypt a block with the public key of another
+ * host that uses the same cyper.
+ * @param block the block to encrypt
+ * @param len the size of the block
+ * @param sessionkey the key used to encrypt
+ * @param iv the initialization vector to use, use INITVALUE
+ *        for streams.
+ * @param result the output parameter in which to store the encrypted result
+ * @returns the size of the encrypted block, -1 for errors
+ */
+int
+GNUNET_CRYPTO_aes_encrypt (const void *block,
+                           uint16_t len,
+                           const struct GNUNET_CRYPTO_AesSessionKey
+                           *sessionkey,
+                           const struct GNUNET_CRYPTO_AesInitializationVector
+                           *iv, void *result)
+{
+  gcry_cipher_hd_t handle;
+  int rc;
+
+  if (sessionkey->crc32 !=
+      htonl (GNUNET_CRYPTO_crc32_n
+             (sessionkey, GNUNET_CRYPTO_AES_KEY_LENGTH)))
+    {
+      GNUNET_break (0);
+      return GNUNET_SYSERR;
+    }
+  GNUNET_assert (0 == gcry_cipher_open (&handle,
+                                        GCRY_CIPHER_AES256,
+                                        GCRY_CIPHER_MODE_CFB, 0));
+  rc = gcry_cipher_setkey (handle, sessionkey, GNUNET_CRYPTO_AES_KEY_LENGTH);
+  GNUNET_assert ((0 == rc) || ((char) rc == GPG_ERR_WEAK_KEY));
+  rc =
+    gcry_cipher_setiv (handle, iv,
+                       sizeof (struct GNUNET_CRYPTO_AesInitializationVector));
+  GNUNET_assert ((0 == rc) || ((char) rc == GPG_ERR_WEAK_KEY));
+  GNUNET_assert (0 == gcry_cipher_encrypt (handle, result, len, block, len));
+  gcry_cipher_close (handle);
+  return len;
+}
+
+/**
+ * Decrypt a given block with the sessionkey.
+ * @param sessionkey the key used to decrypt
+ * @param block the data to decrypt, encoded as returned by encrypt
+ * @param size the size of the block to decrypt
+ * @param iv the initialization vector to use, use INITVALUE
+ *        for streams.
+ * @param result address to store the result at
+ * @return -1 on failure, size of decrypted block on success
+ */
+int
+GNUNET_CRYPTO_aes_decrypt (const struct GNUNET_CRYPTO_AesSessionKey
+                           *sessionkey, const void *block, uint16_t size,
+                           const struct GNUNET_CRYPTO_AesInitializationVector
+                           *iv, void *result)
+{
+  gcry_cipher_hd_t handle;
+  int rc;
+
+  if (sessionkey->crc32 !=
+      htonl (GNUNET_CRYPTO_crc32_n
+             (sessionkey, GNUNET_CRYPTO_AES_KEY_LENGTH)))
+    {
+      GNUNET_break (0);
+      return GNUNET_SYSERR;
+    }
+  GNUNET_assert (0 == gcry_cipher_open (&handle,
+                                        GCRY_CIPHER_AES256,
+                                        GCRY_CIPHER_MODE_CFB, 0));
+  rc = gcry_cipher_setkey (handle, sessionkey, GNUNET_CRYPTO_AES_KEY_LENGTH);
+  GNUNET_assert ((0 == rc) || ((char) rc == GPG_ERR_WEAK_KEY));
+  rc =
+    gcry_cipher_setiv (handle, iv,
+                       sizeof (struct GNUNET_CRYPTO_AesInitializationVector));
+  GNUNET_assert ((0 == rc) || ((char) rc == GPG_ERR_WEAK_KEY));
+  GNUNET_assert (0 ==
+                 gcry_cipher_decrypt (handle, result, size, block, size));
+  gcry_cipher_close (handle);
+  return size;
+}
+
+/* end of crypto_aes.c */