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-rw-r--r--src/include/taler_util.h341
1 files changed, 7 insertions, 334 deletions
diff --git a/src/include/taler_util.h b/src/include/taler_util.h
index 00f139286..f2f319720 100644
--- a/src/include/taler_util.h
+++ b/src/include/taler_util.h
@@ -18,11 +18,15 @@
18 * @brief Interface for common utility functions 18 * @brief Interface for common utility functions
19 * @author Sree Harsha Totakura <sreeharsha@totakura.in> 19 * @author Sree Harsha Totakura <sreeharsha@totakura.in>
20 */ 20 */
21#ifndef TALER_UTIL_H_ 21#ifndef TALER_UTIL_H
22#define TALER_UTIL_H_ 22#define TALER_UTIL_H
23 23
24#include <gnunet/gnunet_util_lib.h> 24#include <gnunet/gnunet_util_lib.h>
25#include <gcrypt.h> 25#include "taler_amount_lib.h"
26#include "taler_crypto_lib.h"
27#include "taler_json_lib.h"
28
29
26 30
27/* Define logging functions */ 31/* Define logging functions */
28#define LOG_DEBUG(...) \ 32#define LOG_DEBUG(...) \
@@ -50,7 +54,6 @@
50 } while(0) 54 } while(0)
51 55
52 56
53
54/** 57/**
55 * Log an error message at log-level 'level' that indicates 58 * Log an error message at log-level 'level' that indicates
56 * a failure of the command 'cmd' with the message given 59 * a failure of the command 'cmd' with the message given
@@ -63,7 +66,6 @@
63 do {int rc; rc = cmd; if (!rc) break; LOG_ERROR("A Gcrypt call failed at %s:%d with error: %s\n", __FILE__, __LINE__, gcry_strerror(rc)); abort(); } while (0) 66 do {int rc; rc = cmd; if (!rc) break; LOG_ERROR("A Gcrypt call failed at %s:%d with error: %s\n", __FILE__, __LINE__, gcry_strerror(rc)); abort(); } while (0)
64 67
65 68
66
67/** 69/**
68 * Initialize Gcrypt library. 70 * Initialize Gcrypt library.
69 */ 71 */
@@ -83,333 +85,4 @@ TALER_config_load (const char *base_dir);
83 85
84 86
85 87
86/* *********************** Amount management ****************** */
87
88
89/**
90 * Number of characters (plus 1 for 0-termination) we use to
91 * represent currency names (i.e. EUR, USD, etc.). We use
92 * 8 for alignment (!).
93 */
94#define TALER_CURRENCY_LEN 8
95
96
97GNUNET_NETWORK_STRUCT_BEGIN
98
99/**
100 * Amount, encoded for network transmission.
101 */
102struct TALER_AmountNBO
103{
104 /**
105 * Value in the main currency, in NBO.
106 */
107 uint32_t value;
108
109 /**
110 * Additinal fractional value, in NBO.
111 */
112 uint32_t fraction;
113
114 /**
115 * Type of the currency being represented.
116 */
117 char currency[TALER_CURRENCY_LEN];
118};
119
120GNUNET_NETWORK_STRUCT_END
121
122
123/**
124 * Representation of monetary value in a given currency.
125 */
126struct TALER_Amount
127{
128 /**
129 * Value (numerator of fraction)
130 */
131 uint32_t value;
132
133 /**
134 * Fraction (denominator of fraction)
135 */
136 uint32_t fraction;
137
138 /**
139 * Currency string, left adjusted and padded with zeros.
140 */
141 char currency[TALER_CURRENCY_LEN];
142};
143
144
145/**
146 * Parse denomination description, in the format "T : V : F".
147 *
148 * @param str denomination description
149 * @param denom denomination to write the result to
150 * @return #GNUNET_OK if the string is a valid denomination specification,
151 * #GNUNET_SYSERR if it is invalid.
152 */
153int
154TALER_string_to_amount (const char *str,
155 struct TALER_Amount *denom);
156
157
158/**
159 * Convert amount from host to network representation.
160 *
161 * @param d amount in host representation
162 * @return amount in network representation
163 */
164struct TALER_AmountNBO
165TALER_amount_hton (struct TALER_Amount d);
166
167
168/**
169 * Convert amount from network to host representation.
170 *
171 * @param d amount in network representation
172 * @return amount in host representation
173 */
174struct TALER_Amount
175TALER_amount_ntoh (struct TALER_AmountNBO dn);
176
177
178/**
179 * Compare the value/fraction of two amounts. Does not compare the currency,
180 * i.e. comparing amounts with the same value and fraction but different
181 * currency would return 0.
182 *
183 * @param a1 first amount
184 * @param a2 second amount
185 * @return result of the comparison
186 */
187int
188TALER_amount_cmp (struct TALER_Amount a1,
189 struct TALER_Amount a2);
190
191
192/**
193 * Perform saturating subtraction of amounts.
194 *
195 * @param a1 amount to subtract from
196 * @param a2 amount to subtract
197 * @return (a1-a2) or 0 if a2>=a1
198 */
199struct TALER_Amount
200TALER_amount_subtract (struct TALER_Amount a1,
201 struct TALER_Amount a2);
202
203
204/**
205 * Perform saturating addition of amounts
206 *
207 * @param a1 first amount to add
208 * @param a2 second amount to add
209 * @return sum of a1 and a2
210 */
211struct TALER_Amount
212TALER_amount_add (struct TALER_Amount a1,
213 struct TALER_Amount a2);
214
215
216/**
217 * Normalize the given amount.
218 *
219 * @param amout amount to normalize
220 * @return normalized amount
221 */
222struct TALER_Amount
223TALER_amount_normalize (struct TALER_Amount amount);
224
225
226/**
227 * Convert amount to string.
228 *
229 * @param amount amount to convert to string
230 * @return freshly allocated string representation
231 */
232char *
233TALER_amount_to_string (struct TALER_Amount amount);
234
235
236/* ****************** Coin crypto primitives ************* */
237
238/**
239 * Public information about a coin (including the public key
240 * of the coin, the denomination key and the signature with
241 * the denomination key).
242 */
243struct TALER_CoinPublicInfo
244{
245 /**
246 * The coin's public key.
247 */
248 struct GNUNET_CRYPTO_EcdsaPublicKey coin_pub;
249
250 /**
251 * Public key representing the denomination of the coin
252 * that is being deposited.
253 */
254 struct GNUNET_CRYPTO_rsa_PublicKey *denom_pub;
255
256 /**
257 * (Unblinded) signature over @e coin_pub with @e denom_pub,
258 * which demonstrates that the coin is valid.
259 */
260 struct GNUNET_CRYPTO_rsa_Signature *denom_sig;
261};
262
263
264/**
265 * Check if a coin is valid; that is, whether the denomination key exists,
266 * is not expired, and the signature is correct.
267 *
268 * @param coin_public_info the coin public info to check for validity
269 * @return #GNUNET_YES if the coin is valid,
270 * #GNUNET_NO if it is invalid
271 * #GNUNET_SYSERROR if an internal error occured
272 */
273int
274TALER_test_coin_valid (const struct TALER_CoinPublicInfo *coin_public_info);
275
276
277/* ****************** Refresh crypto primitives ************* */
278
279/**
280 * Secret used to decrypt the key to decrypt link secrets.
281 */
282struct TALER_TransferSecret
283{
284 /**
285 * Secret used to encrypt/decrypt the `struct TALER_LinkSecret`.
286 * Must be (currently) a hash as this is what
287 * #GNUNET_CRYPTO_ecc_ecdh() returns to us.
288 */
289 struct GNUNET_HashCode key;
290};
291
292
293/**
294 * Secret used to decrypt refresh links.
295 */
296struct TALER_LinkSecret
297{
298 /**
299 * Secret used to decrypt the refresh link data.
300 */
301 char key[sizeof (struct GNUNET_HashCode)];
302};
303
304
305/**
306 * Encrypted secret used to decrypt refresh links.
307 */
308struct TALER_EncryptedLinkSecret
309{
310 /**
311 * Encrypted secret, must be the given size!
312 */
313 char enc[sizeof (struct TALER_LinkSecret)];
314};
315
316
317/**
318 * Representation of an encrypted refresh link.
319 */
320struct TALER_RefreshLinkEncrypted
321{
322
323 /**
324 * Encrypted blinding key with @e blinding_key_enc_size bytes,
325 * must be allocated at the end of this struct.
326 */
327 const char *blinding_key_enc;
328
329 /**
330 * Number of bytes in @e blinding_key_enc.
331 */
332 size_t blinding_key_enc_size;
333
334 /**
335 * Encrypted private key of the coin.
336 */
337 char coin_priv_enc[sizeof (struct GNUNET_CRYPTO_EcdsaPrivateKey)];
338
339};
340
341
342/**
343 * Representation of an refresh link in cleartext.
344 */
345struct TALER_RefreshLinkDecrypted
346{
347
348 /**
349 * Private key of the coin.
350 */
351 struct GNUNET_CRYPTO_EcdsaPrivateKey coin_priv;
352
353 /**
354 * Blinding key with @e blinding_key_enc_size bytes.
355 */
356 struct GNUNET_CRYPTO_rsa_BlindingKey *blinding_key;
357
358};
359
360
361/**
362 * Use the @a trans_sec (from ECDHE) to decrypt the @a secret_enc
363 * to obtain the @a secret to decrypt the linkage data.
364 *
365 * @param secret_enc encrypted secret
366 * @param trans_sec transfer secret
367 * @param secret shared secret for refresh link decryption
368 * @return #GNUNET_OK on success
369 */
370int
371TALER_transfer_decrypt (const struct TALER_EncryptedLinkSecret *secret_enc,
372 const struct TALER_TransferSecret *trans_sec,
373 struct TALER_LinkSecret *secret);
374
375
376/**
377 * Use the @a trans_sec (from ECDHE) to encrypt the @a secret
378 * to obtain the @a secret_enc.
379 *
380 * @param secret shared secret for refresh link decryption
381 * @param trans_sec transfer secret
382 * @param secret_enc[out] encrypted secret
383 * @return #GNUNET_OK on success
384 */
385int
386TALER_transfer_encrypt (const struct TALER_LinkSecret *secret,
387 const struct TALER_TransferSecret *trans_sec,
388 struct TALER_EncryptedLinkSecret *secret_enc);
389
390
391/**
392 * Decrypt refresh link information.
393 *
394 * @param input encrypted refresh link data
395 * @param secret shared secret to use for decryption
396 * @return NULL on error
397 */
398struct TALER_RefreshLinkDecrypted *
399TALER_refresh_decrypt (const struct TALER_RefreshLinkEncrypted *input,
400 const struct TALER_LinkSecret *secret);
401
402
403/**
404 * Encrypt refresh link information.
405 *
406 * @param input plaintext refresh link data
407 * @param secret shared secret to use for encryption
408 * @return NULL on error (should never happen)
409 */
410struct TALER_RefreshLinkEncrypted *
411TALER_refresh_encrypt (const struct TALER_RefreshLinkDecrypted *input,
412 const struct TALER_LinkSecret *secret);
413
414
415#endif 88#endif