3d75dbc088
Encryption and authentication of the meta connection is spread out over meta.c and protocol_auth.c. The new protocol was added there as well, leading to spaghetti code. To improve things, the new protocol will now be implemented in sptps.[ch]. The goal is to have a very simplified version of TLS. There is a record layer, and there are only two record types: application data and handshake messages. The handshake message contains a random nonce, an ephemeral ECDH public key, and an ECDSA signature over the former. After the ECDH public keys are exchanged, a shared secret is calculated, and a TLS style PRF is used to generate the key material for the cipher and HMAC algorithm, and further communication is encrypted and authenticated. A lot of the simplicity comes from the fact that both sides must have each other's public keys in advance, and there are no options to choose. There will be one fixed cipher suite, and both peers always authenticate each other. (Inspiration taken from Ian Grigg's hypotheses[0].) There might be some compromise in the future, to enable or disable encryption, authentication and compression, but there will be no choice of algorithms. This will allow SPTPS to be built with a few embedded crypto algorithms instead of linking with huge crypto libraries. The API is also kept simple. There is a start and a stop function. All data necessary to make the connection work is passed in the start function. Instead having both send- and receive-record functions, there is a send-record function and a receive-data function. The latter will pass protocol data received from the peer to the SPTPS implementation, which will in turn call a receive-record callback function when necessary. This hides all the handshaking from the application, and is completely independent from any event loop or socket characteristics. [0] http://iang.org/ssl/hn_hypotheses_in_secure_protocol_design.html
46 lines
1.8 KiB
C
46 lines
1.8 KiB
C
/*
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digest.h -- header file digest.c
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Copyright (C) 2007 Guus Sliepen <guus@tinc-vpn.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifndef __TINC_DIGEST_H__
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#define __TINC_DIGEST_H__
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#include <openssl/evp.h>
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#define DIGEST_MAX_SIZE EVP_MAX_MD_SIZE
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typedef struct digest {
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const EVP_MD *digest;
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int maclength;
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int keylength;
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char *key;
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} digest_t;
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extern bool digest_open_by_name(struct digest *, const char *name, int maclength);
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extern bool digest_open_by_nid(struct digest *, int nid, int maclength);
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extern bool digest_open_sha1(struct digest *, int maclength);
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extern void digest_close(struct digest *);
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extern bool digest_create(struct digest *, const void *indata, size_t inlen, void *outdata);
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extern bool digest_verify(struct digest *, const void *indata, size_t inlen, const void *digestdata);
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extern bool digest_set_key(struct digest *, const void *key, size_t len);
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extern int digest_get_nid(const struct digest *);
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extern size_t digest_keylength(const struct digest *);
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extern size_t digest_length(const struct digest *);
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extern bool digest_active(const struct digest *);
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#endif
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