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13 General Public License for more details.
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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).
39 GNUNET_CRYPTO_aes_create_session_key (struct GNUNET_CRYPTO_AesSessionKey *key)
41 gcry_randomize (&key->key[0], GNUNET_CRYPTO_AES_KEY_LENGTH,
44 htonl (GNUNET_CRYPTO_crc32_n (key, GNUNET_CRYPTO_AES_KEY_LENGTH));
48 * Check that a new session key is well-formed.
50 * @return GNUNET_OK if the key is valid
53 GNUNET_CRYPTO_aes_check_session_key (const struct GNUNET_CRYPTO_AesSessionKey
58 crc = GNUNET_CRYPTO_crc32_n (key, GNUNET_CRYPTO_AES_KEY_LENGTH);
59 if (ntohl (key->crc32) == crc)
67 * Encrypt a block with the public key of another
68 * host that uses the same cyper.
69 * @param block the block to encrypt
70 * @param len the size of the block
71 * @param sessionkey the key used to encrypt
72 * @param iv the initialization vector to use, use INITVALUE
74 * @param result the output parameter in which to store the encrypted result
75 * @returns the size of the encrypted block, -1 for errors
78 GNUNET_CRYPTO_aes_encrypt (const void *block, size_t len,
79 const struct GNUNET_CRYPTO_AesSessionKey *
81 const struct GNUNET_CRYPTO_AesInitializationVector *
84 gcry_cipher_hd_t handle;
87 if (sessionkey->crc32 !=
88 htonl (GNUNET_CRYPTO_crc32_n (sessionkey, GNUNET_CRYPTO_AES_KEY_LENGTH)))
94 gcry_cipher_open (&handle, GCRY_CIPHER_AES256,
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));
98 rc = gcry_cipher_setiv (handle, iv,
100 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.
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;
128 if (sessionkey->crc32 !=
129 htonl (GNUNET_CRYPTO_crc32_n (sessionkey, GNUNET_CRYPTO_AES_KEY_LENGTH)))
135 gcry_cipher_open (&handle, GCRY_CIPHER_AES256,
136 GCRY_CIPHER_MODE_CFB, 0));
137 rc = gcry_cipher_setkey (handle, sessionkey, GNUNET_CRYPTO_AES_KEY_LENGTH);
138 GNUNET_assert ((0 == rc) || ((char) rc == GPG_ERR_WEAK_KEY));
139 rc = gcry_cipher_setiv (handle, iv,
141 GNUNET_CRYPTO_AesInitializationVector));
142 GNUNET_assert ((0 == rc) || ((char) rc == GPG_ERR_WEAK_KEY));
143 GNUNET_assert (0 == gcry_cipher_decrypt (handle, result, size, block, size));
144 gcry_cipher_close (handle);
149 * @brief Derive an IV
150 * @param iv initialization vector
151 * @param skey session key
152 * @param salt salt for the derivation
153 * @param salt_len size of the salt
154 * @param ... pairs of void * & size_t for context chunks, terminated by NULL
157 GNUNET_CRYPTO_aes_derive_iv (struct GNUNET_CRYPTO_AesInitializationVector *iv,
158 const struct GNUNET_CRYPTO_AesSessionKey *skey,
159 const void *salt, size_t salt_len, ...)
163 va_start (argp, salt_len);
164 GNUNET_CRYPTO_aes_derive_iv_v (iv, skey, salt, salt_len, argp);
169 * @brief Derive an IV
170 * @param iv initialization vector
171 * @param skey session key
172 * @param salt salt for the derivation
173 * @param salt_len size of the salt
174 * @param argp pairs of void * & size_t for context chunks, terminated by NULL
177 GNUNET_CRYPTO_aes_derive_iv_v (struct GNUNET_CRYPTO_AesInitializationVector *iv,
178 const struct GNUNET_CRYPTO_AesSessionKey *skey,
179 const void *salt, size_t salt_len, va_list argp)
181 GNUNET_CRYPTO_kdf_v (iv->iv, sizeof (iv->iv), salt, salt_len, skey->key,
182 sizeof (skey->key), argp);
185 /* end of crypto_aes.c */