2 This file is part of GNUnet.
3 (C) 2001, 2002, 2003, 2004, 2005, 2006 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
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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
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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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"
33 #define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)
36 * Create a new SessionKey (for AES-256).
38 * @param key session key to initialize
41 GNUNET_CRYPTO_aes_create_session_key (struct GNUNET_CRYPTO_AesSessionKey *key)
43 gcry_randomize (&key->key[0], GNUNET_CRYPTO_AES_KEY_LENGTH,
49 * Initialize AES cipher.
51 * @param handle handle to initialize
52 * @param sessionkey session key to use
53 * @param iv initialization vector to use
54 * @return GNUNET_OK on success, GNUNET_SYSERR on error
57 setup_cipher (gcry_cipher_hd_t *handle,
58 const struct GNUNET_CRYPTO_AesSessionKey *
60 const struct GNUNET_CRYPTO_AesInitializationVector *
66 gcry_cipher_open (handle, GCRY_CIPHER_AES256,
67 GCRY_CIPHER_MODE_CFB, 0));
68 rc = gcry_cipher_setkey (*handle, sessionkey, GNUNET_CRYPTO_AES_KEY_LENGTH);
69 GNUNET_assert ((0 == rc) || ((char) rc == GPG_ERR_WEAK_KEY));
70 rc = gcry_cipher_setiv (*handle, iv,
72 GNUNET_CRYPTO_AesInitializationVector));
73 GNUNET_assert ((0 == rc) || ((char) rc == GPG_ERR_WEAK_KEY));
79 * Encrypt a block with the public key of another
80 * host that uses the same cyper.
82 * @param block the block to encrypt
83 * @param len the size of the block
84 * @param sessionkey the key used to encrypt
85 * @param iv the initialization vector to use, use INITVALUE
87 * @param result the output parameter in which to store the encrypted result
88 * @returns the size of the encrypted block, -1 for errors
91 GNUNET_CRYPTO_aes_encrypt (const void *block, size_t len,
92 const struct GNUNET_CRYPTO_AesSessionKey *
94 const struct GNUNET_CRYPTO_AesInitializationVector *
97 gcry_cipher_hd_t handle;
99 if (GNUNET_OK != setup_cipher (&handle, sessionkey, iv))
101 GNUNET_assert (0 == gcry_cipher_encrypt (handle, result, len, block, len));
102 gcry_cipher_close (handle);
108 * Decrypt a given block with the sessionkey.
110 * @param block the data to decrypt, encoded as returned by encrypt
111 * @param size the size of the block to decrypt
112 * @param sessionkey the key used to decrypt
113 * @param iv the initialization vector to use, use INITVALUE
115 * @param result address to store the result at
116 * @return -1 on failure, size of decrypted block on success
119 GNUNET_CRYPTO_aes_decrypt (const void *block, size_t size,
120 const struct GNUNET_CRYPTO_AesSessionKey *
122 const struct GNUNET_CRYPTO_AesInitializationVector *
125 gcry_cipher_hd_t handle;
127 if (GNUNET_OK != setup_cipher (&handle, sessionkey, iv))
129 GNUNET_assert (0 == gcry_cipher_decrypt (handle, result, size, block, size));
130 gcry_cipher_close (handle);
136 * @brief Derive an IV
138 * @param iv initialization vector
139 * @param skey session key
140 * @param salt salt for the derivation
141 * @param salt_len size of the salt
142 * @param ... pairs of void * & size_t for context chunks, terminated by NULL
145 GNUNET_CRYPTO_aes_derive_iv (struct GNUNET_CRYPTO_AesInitializationVector *iv,
146 const struct GNUNET_CRYPTO_AesSessionKey *skey,
147 const void *salt, size_t salt_len, ...)
151 va_start (argp, salt_len);
152 GNUNET_CRYPTO_aes_derive_iv_v (iv, skey, salt, salt_len, argp);
158 * @brief Derive an IV
160 * @param iv initialization vector
161 * @param skey session key
162 * @param salt salt for the derivation
163 * @param salt_len size of the salt
164 * @param argp pairs of void * & size_t for context chunks, terminated by NULL
167 GNUNET_CRYPTO_aes_derive_iv_v (struct GNUNET_CRYPTO_AesInitializationVector *iv,
168 const struct GNUNET_CRYPTO_AesSessionKey *skey,
169 const void *salt, size_t salt_len, va_list argp)
171 GNUNET_CRYPTO_kdf_v (iv->iv, sizeof (iv->iv), salt, salt_len, skey->key,
172 sizeof (skey->key), argp);
175 /* end of crypto_aes.c */