1: /*
2: * Copyright (C) 2010 Tobias Brunner
3: * Copyright (C) 2005-2007 Martin Willi
4: * Copyright (C) 2005 Jan Hutter
5: * HSR Hochschule fuer Technik Rapperswil
6: *
7: * This program is free software; you can redistribute it and/or modify it
8: * under the terms of the GNU General Public License as published by the
9: * Free Software Foundation; either version 2 of the License, or (at your
10: * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
11: *
12: * This program is distributed in the hope that it will be useful, but
13: * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14: * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15: * for more details.
16: */
17:
18: /**
19: * @defgroup diffie_hellman diffie_hellman
20: * @{ @ingroup crypto
21: */
22:
23: #ifndef DIFFIE_HELLMAN_H_
24: #define DIFFIE_HELLMAN_H_
25:
26: typedef enum diffie_hellman_group_t diffie_hellman_group_t;
27: typedef struct diffie_hellman_t diffie_hellman_t;
28: typedef struct diffie_hellman_params_t diffie_hellman_params_t;
29:
30: #include <library.h>
31:
32: /**
33: * Diffie-Hellman group.
34: *
35: * The modulus (or group) to use for a Diffie-Hellman calculation.
36: * See IKEv2 RFC 3.3.2 and RFC 3526.
37: *
38: * ECP groups are defined in RFC 4753 and RFC 5114.
39: * ECC Brainpool groups are defined in RFC 6954.
40: * Curve25519 and Curve448 groups are defined in RFC 8031.
41: */
42: enum diffie_hellman_group_t {
43: MODP_NONE = 0,
44: MODP_768_BIT = 1,
45: MODP_1024_BIT = 2,
46: MODP_1536_BIT = 5,
47: MODP_2048_BIT = 14,
48: MODP_3072_BIT = 15,
49: MODP_4096_BIT = 16,
50: MODP_6144_BIT = 17,
51: MODP_8192_BIT = 18,
52: ECP_256_BIT = 19,
53: ECP_384_BIT = 20,
54: ECP_521_BIT = 21,
55: MODP_1024_160 = 22,
56: MODP_2048_224 = 23,
57: MODP_2048_256 = 24,
58: ECP_192_BIT = 25,
59: ECP_224_BIT = 26,
60: ECP_224_BP = 27,
61: ECP_256_BP = 28,
62: ECP_384_BP = 29,
63: ECP_512_BP = 30,
64: CURVE_25519 = 31,
65: CURVE_448 = 32,
66: /** insecure NULL diffie hellman group for testing, in PRIVATE USE */
67: MODP_NULL = 1024,
68: /** MODP group with custom generator/prime */
69: /** Parameters defined by IEEE 1363.1, in PRIVATE USE */
70: NTRU_112_BIT = 1030,
71: NTRU_128_BIT = 1031,
72: NTRU_192_BIT = 1032,
73: NTRU_256_BIT = 1033,
74: NH_128_BIT = 1040,
75: /** internally used DH group with additional parameters g and p, outside
76: * of PRIVATE USE (i.e. IKEv2 DH group range) so it can't be negotiated */
77: MODP_CUSTOM = 65536,
78: };
79:
80: /**
81: * enum name for diffie_hellman_group_t.
82: */
83: extern enum_name_t *diffie_hellman_group_names;
84:
85: /**
86: * enum names for diffie_hellman_group_t (matching proposal keywords).
87: */
88: extern enum_name_t *diffie_hellman_group_names_short;
89:
90: /**
91: * Implementation of the Diffie-Hellman algorithm, as in RFC2631.
92: */
93: struct diffie_hellman_t {
94:
95: /**
96: * Returns the shared secret of this diffie hellman exchange.
97: *
98: * Space for returned secret is allocated and must be freed by the caller.
99: *
100: * @param secret shared secret will be written into this chunk
101: * @return TRUE if shared secret computed successfully
102: */
103: bool (*get_shared_secret)(diffie_hellman_t *this, chunk_t *secret)
104: __attribute__((warn_unused_result));
105:
106: /**
107: * Sets the public value of partner.
108: *
109: * Chunk gets cloned and can be destroyed afterwards.
110: *
111: * @param value public value of partner
112: * @return TRUE if other public value verified and set
113: */
114: bool (*set_other_public_value)(diffie_hellman_t *this, chunk_t value)
115: __attribute__((warn_unused_result));
116:
117: /**
118: * Gets the own public value to transmit.
119: *
120: * Space for returned chunk is allocated and must be freed by the caller.
121: *
122: * @param value public value of caller is stored at this location
123: * @return TRUE if public value retrieved
124: */
125: bool (*get_my_public_value) (diffie_hellman_t *this, chunk_t *value)
126: __attribute__((warn_unused_result));
127:
128: /**
129: * Set an explicit own private value to use.
130: *
131: * Calling this method is usually not required, as the DH backend generates
132: * an appropriate private value itself. It is optional to implement, and
133: * used mostly for testing purposes.
134: *
135: * @param value private value to set
136: */
137: bool (*set_private_value)(diffie_hellman_t *this, chunk_t value)
138: __attribute__((warn_unused_result));
139:
140: /**
141: * Get the DH group used.
142: *
143: * @return DH group set in construction
144: */
145: diffie_hellman_group_t (*get_dh_group) (diffie_hellman_t *this);
146:
147: /**
148: * Destroys a diffie_hellman_t object.
149: */
150: void (*destroy) (diffie_hellman_t *this);
151: };
152:
153: /**
154: * Parameters for a specific diffie hellman group.
155: */
156: struct diffie_hellman_params_t {
157:
158: /**
159: * The prime of the group
160: */
161: const chunk_t prime;
162:
163: /**
164: * Generator of the group
165: */
166: const chunk_t generator;
167:
168: /**
169: * Exponent length to use
170: */
171: size_t exp_len;
172:
173: /**
174: * Prime order subgroup; for MODP Groups 22-24
175: */
176: const chunk_t subgroup;
177: };
178:
179: /**
180: * Initialize diffie hellman parameters during startup.
181: */
182: void diffie_hellman_init();
183:
184: /**
185: * Get the parameters associated with the specified diffie hellman group.
186: *
187: * Before calling this method, use diffie_hellman_init() to initialize the
188: * DH group table. This is usually done by library_init().
189: *
190: * @param group DH group
191: * @return The parameters or NULL, if the group is not supported
192: */
193: diffie_hellman_params_t *diffie_hellman_get_params(diffie_hellman_group_t group);
194:
195: /**
196: * Check if a given DH group is an ECDH group
197: *
198: * @param group group to check
199: * @return TRUE if group is an ECP group
200: */
201: bool diffie_hellman_group_is_ec(diffie_hellman_group_t group);
202:
203: /**
204: * Check if a diffie hellman public value is valid for given group.
205: *
206: * @param group group the value is used in
207: * @param value public DH value to check
208: * @return TRUE if value looks valid for group
209: */
210: bool diffie_hellman_verify_value(diffie_hellman_group_t group, chunk_t value);
211:
212: #endif /** DIFFIE_HELLMAN_H_ @}*/
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