1 /* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
2 /* include/k5-spake.h - SPAKE preauth mech declarations */
4 * Copyright (C) 2015 by the Massachusetts Institute of Technology.
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34 * The SPAKE preauth mechanism allows long-term client keys to be used for
35 * preauthentication without exposing them to offline dictionary attacks. The
36 * negotiated key can also be used for second-factor authentication. This
37 * header file declares structures and encoder/decoder functions for the
38 * mechanism's padata messages.
46 /* SPAKESecondFactor is contained within a SPAKEChallenge, SPAKEResponse, or
47 * EncryptedData message and contains a second-factor challenge or response. */
48 typedef struct krb5_spake_factor_st {
53 /* SPAKESupport is sent from the client to the KDC to indicate which group the
55 typedef struct krb5_spake_support_st {
60 /* SPAKEChallenge is sent from the KDC to the client to communicate its group
61 * selection, public value, and second-factor challenge options. */
62 typedef struct krb5_spake_challenge_st {
65 krb5_spake_factor **factors;
66 } krb5_spake_challenge;
68 /* SPAKEResponse is sent from the client to the KDC to communicate its public
69 * value and encrypted second-factor response. */
70 typedef struct krb5_spake_response_st {
73 } krb5_spake_response;
75 enum krb5_spake_msgtype {
76 SPAKE_MSGTYPE_UNKNOWN = -1,
77 SPAKE_MSGTYPE_SUPPORT = 0,
78 SPAKE_MSGTYPE_CHALLENGE = 1,
79 SPAKE_MSGTYPE_RESPONSE = 2,
80 SPAKE_MSGTYPE_ENCDATA = 3
83 /* PA-SPAKE is a choice among the message types which can appear in a PA-SPAKE
85 typedef struct krb5_pa_spake_st {
86 enum krb5_spake_msgtype choice;
87 union krb5_spake_message_choices {
88 krb5_spake_support support;
89 krb5_spake_challenge challenge;
90 krb5_spake_response response;
91 krb5_enc_data encdata;
95 krb5_error_code encode_krb5_spake_factor(const krb5_spake_factor *val,
96 krb5_data **code_out);
97 krb5_error_code decode_krb5_spake_factor(const krb5_data *code,
98 krb5_spake_factor **val_out);
99 void k5_free_spake_factor(krb5_context context, krb5_spake_factor *val);
101 krb5_error_code encode_krb5_pa_spake(const krb5_pa_spake *val,
102 krb5_data **code_out);
103 krb5_error_code decode_krb5_pa_spake(const krb5_data *code,
104 krb5_pa_spake **val_out);
105 void k5_free_pa_spake(krb5_context context, krb5_pa_spake *val);
107 #endif /* K5_SPAKE_H */