1 /*
2  * Implement J-PAKE, as described in
3  * http://grouper.ieee.org/groups/1363/Research/contributions/hao-ryan-2008.pdf
4  *
5  * With hints from http://www.cl.cam.ac.uk/~fh240/software/JPAKE2.java.
6  */
7 
8 #ifndef HEADER_JPAKE_H
9 # define HEADER_JPAKE_H
10 
11 # include <openssl/opensslconf.h>
12 
13 # ifdef OPENSSL_NO_JPAKE
14 #  error JPAKE is disabled.
15 # endif
16 
17 #ifdef  __cplusplus
18 extern "C" {
19 #endif
20 
21 # include <openssl/bn.h>
22 # include <openssl/sha.h>
23 
24 typedef struct JPAKE_CTX JPAKE_CTX;
25 
26 /* Note that "g" in the ZKPs is not necessarily the J-PAKE g. */
27 typedef struct {
28     BIGNUM *gr;                 /* g^r (r random) */
29     BIGNUM *b;                  /* b = r - x*h, h=hash(g, g^r, g^x, name) */
30 } JPAKE_ZKP;
31 
32 typedef struct {
33     BIGNUM *gx;                 /* g^x in step 1, g^(xa + xc + xd) * xb * s
34                                  * in step 2 */
35     JPAKE_ZKP zkpx;             /* ZKP(x) or ZKP(xb * s) */
36 } JPAKE_STEP_PART;
37 
38 typedef struct {
39     JPAKE_STEP_PART p1;         /* g^x3, ZKP(x3) or g^x1, ZKP(x1) */
40     JPAKE_STEP_PART p2;         /* g^x4, ZKP(x4) or g^x2, ZKP(x2) */
41 } JPAKE_STEP1;
42 
43 typedef JPAKE_STEP_PART JPAKE_STEP2;
44 
45 typedef struct {
46     unsigned char hhk[SHA_DIGEST_LENGTH];
47 } JPAKE_STEP3A;
48 
49 typedef struct {
50     unsigned char hk[SHA_DIGEST_LENGTH];
51 } JPAKE_STEP3B;
52 
53 /* Parameters are copied */
54 JPAKE_CTX *JPAKE_CTX_new(const char *name, const char *peer_name,
55                          const BIGNUM *p, const BIGNUM *g, const BIGNUM *q,
56                          const BIGNUM *secret);
57 void JPAKE_CTX_free(JPAKE_CTX *ctx);
58 
59 /*
60  * Note that JPAKE_STEP1 can be used multiple times before release
61  * without another init.
62  */
63 void JPAKE_STEP1_init(JPAKE_STEP1 *s1);
64 int JPAKE_STEP1_generate(JPAKE_STEP1 *send, JPAKE_CTX *ctx);
65 int JPAKE_STEP1_process(JPAKE_CTX *ctx, const JPAKE_STEP1 *received);
66 void JPAKE_STEP1_release(JPAKE_STEP1 *s1);
67 
68 /*
69  * Note that JPAKE_STEP2 can be used multiple times before release
70  * without another init.
71  */
72 void JPAKE_STEP2_init(JPAKE_STEP2 *s2);
73 int JPAKE_STEP2_generate(JPAKE_STEP2 *send, JPAKE_CTX *ctx);
74 int JPAKE_STEP2_process(JPAKE_CTX *ctx, const JPAKE_STEP2 *received);
75 void JPAKE_STEP2_release(JPAKE_STEP2 *s2);
76 
77 /*
78  * Optionally verify the shared key. If the shared secrets do not
79  * match, the two ends will disagree about the shared key, but
80  * otherwise the protocol will succeed.
81  */
82 void JPAKE_STEP3A_init(JPAKE_STEP3A *s3a);
83 int JPAKE_STEP3A_generate(JPAKE_STEP3A *send, JPAKE_CTX *ctx);
84 int JPAKE_STEP3A_process(JPAKE_CTX *ctx, const JPAKE_STEP3A *received);
85 void JPAKE_STEP3A_release(JPAKE_STEP3A *s3a);
86 
87 void JPAKE_STEP3B_init(JPAKE_STEP3B *s3b);
88 int JPAKE_STEP3B_generate(JPAKE_STEP3B *send, JPAKE_CTX *ctx);
89 int JPAKE_STEP3B_process(JPAKE_CTX *ctx, const JPAKE_STEP3B *received);
90 void JPAKE_STEP3B_release(JPAKE_STEP3B *s3b);
91 
92 /*
93  * the return value belongs to the library and will be released when
94  * ctx is released, and will change when a new handshake is performed.
95  */
96 const BIGNUM *JPAKE_get_shared_key(JPAKE_CTX *ctx);
97 
98 /* BEGIN ERROR CODES */
99 /*
100  * The following lines are auto generated by the script mkerr.pl. Any changes
101  * made after this point may be overwritten when the script is next run.
102  */
103 void ERR_load_JPAKE_strings(void);
104 
105 /* Error codes for the JPAKE functions. */
106 
107 /* Function codes. */
108 # define JPAKE_F_JPAKE_STEP1_PROCESS                      101
109 # define JPAKE_F_JPAKE_STEP2_PROCESS                      102
110 # define JPAKE_F_JPAKE_STEP3A_PROCESS                     103
111 # define JPAKE_F_JPAKE_STEP3B_PROCESS                     104
112 # define JPAKE_F_VERIFY_ZKP                               100
113 
114 /* Reason codes. */
115 # define JPAKE_R_G_TO_THE_X3_IS_NOT_LEGAL                 108
116 # define JPAKE_R_G_TO_THE_X4_IS_NOT_LEGAL                 109
117 # define JPAKE_R_G_TO_THE_X4_IS_ONE                       105
118 # define JPAKE_R_HASH_OF_HASH_OF_KEY_MISMATCH             106
119 # define JPAKE_R_HASH_OF_KEY_MISMATCH                     107
120 # define JPAKE_R_VERIFY_B_FAILED                          102
121 # define JPAKE_R_VERIFY_X3_FAILED                         103
122 # define JPAKE_R_VERIFY_X4_FAILED                         104
123 # define JPAKE_R_ZKP_VERIFY_FAILED                        100
124 
125 #ifdef  __cplusplus
126 }
127 #endif
128 #endif
129