2 This file is part of GNUnet.
3 (C) 2001, 2002, 2003, 2004, 2005, 2006 Christian Grothoff (and other contributing authors)
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6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 2, or (at your
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11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
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16 along with GNUnet; see the file COPYING. If not, write to the
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22 * @file util/crypto_aes.c
23 * @brief Symmetric encryption services.
24 * @author Christian Grothoff
25 * @author Ioana Patrascu
29 #include "gnunet_common.h"
30 #include "gnunet_crypto_lib.h"
34 * Create a new SessionKey (for AES-256).
37 GNUNET_CRYPTO_aes_create_session_key (struct GNUNET_CRYPTO_AesSessionKey *key)
39 gcry_randomize (&key->key[0], GNUNET_CRYPTO_AES_KEY_LENGTH,
42 htonl (GNUNET_CRYPTO_crc32_n (key, GNUNET_CRYPTO_AES_KEY_LENGTH));
46 * Check that a new session key is well-formed.
48 * @return GNUNET_OK if the key is valid
51 GNUNET_CRYPTO_aes_check_session_key (const struct GNUNET_CRYPTO_AesSessionKey
56 crc = GNUNET_CRYPTO_crc32_n (key, GNUNET_CRYPTO_AES_KEY_LENGTH);
57 if (ntohl (key->crc32) == crc)
65 * Encrypt a block with the public key of another
66 * host that uses the same cyper.
67 * @param block the block to encrypt
68 * @param len the size of the block
69 * @param sessionkey the key used to encrypt
70 * @param iv the initialization vector to use, use INITVALUE
72 * @param result the output parameter in which to store the encrypted result
73 * @returns the size of the encrypted block, -1 for errors
76 GNUNET_CRYPTO_aes_encrypt (const void *block,
78 const struct GNUNET_CRYPTO_AesSessionKey
80 const struct GNUNET_CRYPTO_AesInitializationVector
83 gcry_cipher_hd_t handle;
86 if (sessionkey->crc32 !=
87 htonl (GNUNET_CRYPTO_crc32_n
88 (sessionkey, GNUNET_CRYPTO_AES_KEY_LENGTH)))
93 GNUNET_assert (0 == gcry_cipher_open (&handle,
95 GCRY_CIPHER_MODE_CFB, 0));
96 rc = gcry_cipher_setkey (handle, sessionkey, GNUNET_CRYPTO_AES_KEY_LENGTH);
97 GNUNET_assert ((0 == rc) || ((char) rc == GPG_ERR_WEAK_KEY));
99 gcry_cipher_setiv (handle, iv,
100 sizeof (struct GNUNET_CRYPTO_AesInitializationVector));
101 GNUNET_assert ((0 == rc) || ((char) rc == GPG_ERR_WEAK_KEY));
102 GNUNET_assert (0 == gcry_cipher_encrypt (handle, result, len, block, len));
103 gcry_cipher_close (handle);
108 * Decrypt a given block with the sessionkey.
109 * @param sessionkey the key used to decrypt
110 * @param block the data to decrypt, encoded as returned by encrypt
111 * @param size the size of the block to decrypt
112 * @param iv the initialization vector to use, use INITVALUE
114 * @param result address to store the result at
115 * @return -1 on failure, size of decrypted block on success
118 GNUNET_CRYPTO_aes_decrypt (const struct GNUNET_CRYPTO_AesSessionKey
119 *sessionkey, const void *block, uint16_t size,
120 const struct GNUNET_CRYPTO_AesInitializationVector
123 gcry_cipher_hd_t handle;
126 if (sessionkey->crc32 !=
127 htonl (GNUNET_CRYPTO_crc32_n
128 (sessionkey, GNUNET_CRYPTO_AES_KEY_LENGTH)))
131 return GNUNET_SYSERR;
133 GNUNET_assert (0 == gcry_cipher_open (&handle,
135 GCRY_CIPHER_MODE_CFB, 0));
136 rc = gcry_cipher_setkey (handle, sessionkey, GNUNET_CRYPTO_AES_KEY_LENGTH);
137 GNUNET_assert ((0 == rc) || ((char) rc == GPG_ERR_WEAK_KEY));
139 gcry_cipher_setiv (handle, iv,
140 sizeof (struct GNUNET_CRYPTO_AesInitializationVector));
141 GNUNET_assert ((0 == rc) || ((char) rc == GPG_ERR_WEAK_KEY));
143 gcry_cipher_decrypt (handle, result, size, block, size));
144 gcry_cipher_close (handle);
148 /* end of crypto_aes.c */