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/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* include/k5-spake.h - SPAKE preauth mech declarations */
/*
* Copyright (C) 2015 by the Massachusetts Institute of Technology.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* The SPAKE preauth mechanism allows long-term client keys to be used for
* preauthentication without exposing them to offline dictionary attacks. The
* negotiated key can also be used for second-factor authentication. This
* header file declares structures and encoder/decoder functions for the
* mechanism's padata messages.
*/
#ifndef K5_SPAKE_H
#define K5_SPAKE_H
#include "k5-int.h"
/* SPAKESecondFactor is contained within a SPAKEChallenge, SPAKEResponse, or
* EncryptedData message and contains a second-factor challenge or response. */
typedef struct krb5_spake_factor_st {
int32_t type;
krb5_data *data;
} krb5_spake_factor;
/* SPAKESupport is sent from the client to the KDC to indicate which group the
* client supports. */
typedef struct krb5_spake_support_st {
int32_t ngroups;
int32_t *groups;
} krb5_spake_support;
/* SPAKEChallenge is sent from the KDC to the client to communicate its group
* selection, public value, and second-factor challenge options. */
typedef struct krb5_spake_challenge_st {
int32_t group;
krb5_data pubkey;
krb5_spake_factor **factors;
} krb5_spake_challenge;
/* SPAKEResponse is sent from the client to the KDC to communicate its public
* value and encrypted second-factor response. */
typedef struct krb5_spake_response_st {
krb5_data pubkey;
krb5_enc_data factor;
} krb5_spake_response;
enum krb5_spake_msgtype {
SPAKE_MSGTYPE_UNKNOWN = -1,
SPAKE_MSGTYPE_SUPPORT = 0,
SPAKE_MSGTYPE_CHALLENGE = 1,
SPAKE_MSGTYPE_RESPONSE = 2,
SPAKE_MSGTYPE_ENCDATA = 3
};
/* PA-SPAKE is a choice among the message types which can appear in a PA-SPAKE
* padata element. */
typedef struct krb5_pa_spake_st {
enum krb5_spake_msgtype choice;
union krb5_spake_message_choices {
krb5_spake_support support;
krb5_spake_challenge challenge;
krb5_spake_response response;
krb5_enc_data encdata;
} u;
} krb5_pa_spake;
krb5_error_code encode_krb5_spake_factor(const krb5_spake_factor *val,
krb5_data **code_out);
krb5_error_code decode_krb5_spake_factor(const krb5_data *code,
krb5_spake_factor **val_out);
void k5_free_spake_factor(krb5_context context, krb5_spake_factor *val);
krb5_error_code encode_krb5_pa_spake(const krb5_pa_spake *val,
krb5_data **code_out);
krb5_error_code decode_krb5_pa_spake(const krb5_data *code,
krb5_pa_spake **val_out);
void k5_free_pa_spake(krb5_context context, krb5_pa_spake *val);
#endif /* K5_SPAKE_H */
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