2 This file is part of GNUnet.
3 (C) 2001, 2002, 2003, 2004, 2005, 2006, 2009 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 2, or (at your
8 option) any later version.
10 GNUnet is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with GNUnet; see the file COPYING. If not, write to the
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA.
22 * @file util/crypto_rsa.c
23 * @brief public key cryptography (RSA) with libgcrypt
24 * @author Christian Grothoff
26 * Note that the code locks often needlessly on the gcrypt-locking api.
27 * One would think that simple MPI operations should not require locking
28 * (since only global operations on the random pool must be locked,
29 * strictly speaking). But libgcrypt does sometimes require locking in
30 * unexpected places, so the safe solution is to always lock even if it
31 * is not required. The performance impact is minimal anyway.
36 #include "gnunet_common.h"
37 #include "gnunet_crypto_lib.h"
38 #include "gnunet_disk_lib.h"
41 * The private information of an RSA key pair.
42 * NOTE: this must match the definition in crypto_ksk.c
44 struct GNUNET_CRYPTO_RsaPrivateKey
51 * GNUnet mandates a certain format for the encoding
52 * of private RSA key information that is provided
53 * by the RSA implementations. This format is used
54 * to serialize a private RSA key (typically when
55 * writing it to disk).
57 struct RsaPrivateKeyBinaryEncoded
60 * Total size of the structure, in bytes, in big-endian!
62 uint16_t len GNUNET_PACKED;
63 uint16_t sizen GNUNET_PACKED; /* in big-endian! */
64 uint16_t sizee GNUNET_PACKED; /* in big-endian! */
65 uint16_t sized GNUNET_PACKED; /* in big-endian! */
66 uint16_t sizep GNUNET_PACKED; /* in big-endian! */
67 uint16_t sizeq GNUNET_PACKED; /* in big-endian! */
68 uint16_t sizedmp1 GNUNET_PACKED; /* in big-endian! */
69 uint16_t sizedmq1 GNUNET_PACKED; /* in big-endian! */
70 /* followed by the actual values */
74 #define HOSTKEY_LEN 2048
76 #define EXTRA_CHECKS ALLOW_EXTRA_CHECKS
80 * Log an error message at log-level 'level' that indicates
81 * a failure of the command 'cmd' with the message given
82 * by gcry_strerror(rc).
84 #define LOG_GCRY(level, cmd, rc) do { GNUNET_log(level, _("`%s' failed at %s:%d with error: %s\n"), cmd, __FILE__, __LINE__, gcry_strerror(rc)); } while(0);
87 * If target != size, move target bytes to the
88 * end of the size-sized buffer and zero out the
89 * first target-size bytes.
92 adjust (unsigned char *buf, size_t size, size_t target)
96 memmove (&buf[target - size], buf, size);
97 memset (buf, 0, target - size);
102 * This HostKey implementation uses RSA.
104 struct GNUNET_CRYPTO_RsaPrivateKey *
105 GNUNET_CRYPTO_rsa_key_create ()
107 struct GNUNET_CRYPTO_RsaPrivateKey *ret;
109 gcry_sexp_t s_keyparam;
111 GNUNET_assert (0 == gcry_sexp_build (&s_keyparam,
113 "(genkey(rsa(nbits %d)(rsa-use-e 3:257)))",
115 GNUNET_assert (0 == gcry_pk_genkey (&s_key, s_keyparam));
116 gcry_sexp_release (s_keyparam);
118 GNUNET_assert (0 == gcry_pk_testkey (s_key));
120 ret = GNUNET_malloc (sizeof (struct GNUNET_CRYPTO_RsaPrivateKey));
126 * Free memory occupied by hostkey
129 GNUNET_CRYPTO_rsa_key_free (struct GNUNET_CRYPTO_RsaPrivateKey *hostkey)
131 gcry_sexp_release (hostkey->sexp);
132 GNUNET_free (hostkey);
136 key_from_sexp (gcry_mpi_t * array,
137 gcry_sexp_t sexp, const char *topname, const char *elems)
139 gcry_sexp_t list, l2;
143 list = gcry_sexp_find_token (sexp, topname, 0);
148 l2 = gcry_sexp_cadr (list);
149 gcry_sexp_release (list);
157 for (s = elems; *s; s++, idx++)
159 l2 = gcry_sexp_find_token (list, s, 1);
162 for (i = 0; i < idx; i++)
164 gcry_free (array[i]);
167 gcry_sexp_release (list);
168 return 3; /* required parameter not found */
170 array[idx] = gcry_sexp_nth_mpi (l2, 1, GCRYMPI_FMT_USG);
171 gcry_sexp_release (l2);
174 for (i = 0; i < idx; i++)
176 gcry_free (array[i]);
179 gcry_sexp_release (list);
180 return 4; /* required parameter is invalid */
183 gcry_sexp_release (list);
188 * Extract the public key of the host.
189 * @param priv the private key
190 * @param pub where to write the public key
193 GNUNET_CRYPTO_rsa_key_get_public (const struct GNUNET_CRYPTO_RsaPrivateKey
196 GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded *pub)
202 rc = key_from_sexp (skey, priv->sexp, "public-key", "ne");
204 rc = key_from_sexp (skey, priv->sexp, "private-key", "ne");
206 rc = key_from_sexp (skey, priv->sexp, "rsa", "ne");
207 GNUNET_assert (0 == rc);
209 htons (sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded) -
210 sizeof (pub->padding));
211 pub->sizen = htons (GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH);
213 size = GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH;
214 GNUNET_assert (0 == gcry_mpi_print (GCRYMPI_FMT_USG,
215 &pub->key[0], size, &size, skey[0]));
216 adjust (&pub->key[0], size, GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH);
217 size = GNUNET_CRYPTO_RSA_KEY_LENGTH - GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH;
219 gcry_mpi_print (GCRYMPI_FMT_USG,
221 [GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH],
222 size, &size, skey[1]));
223 adjust (&pub->key[GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH], size,
224 GNUNET_CRYPTO_RSA_KEY_LENGTH -
225 GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH);
226 gcry_mpi_release (skey[0]);
227 gcry_mpi_release (skey[1]);
232 * Internal: publicKey => RSA-Key.
234 * Note that the return type is not actually a private
235 * key but rather an sexpression for the public key!
237 static struct GNUNET_CRYPTO_RsaPrivateKey *
238 public2PrivateKey (const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
241 struct GNUNET_CRYPTO_RsaPrivateKey *ret;
249 if ((ntohs (publicKey->sizen) != GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH) ||
250 (ntohs (publicKey->len) !=
251 sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded) -
252 sizeof (publicKey->padding)))
257 size = GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH;
258 rc = gcry_mpi_scan (&n, GCRYMPI_FMT_USG, &publicKey->key[0], size, &size);
261 LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_mpi_scan", rc);
264 size = GNUNET_CRYPTO_RSA_KEY_LENGTH - GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH;
265 rc = gcry_mpi_scan (&e, GCRYMPI_FMT_USG,
266 &publicKey->key[GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH],
270 LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_mpi_scan", rc);
271 gcry_mpi_release (n);
274 rc = gcry_sexp_build (&result,
275 &erroff, "(public-key(rsa(n %m)(e %m)))", n, e);
276 gcry_mpi_release (n);
277 gcry_mpi_release (e);
280 LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_sexp_build", rc); /* erroff gives more info */
283 ret = GNUNET_malloc (sizeof (struct GNUNET_CRYPTO_RsaPrivateKey));
290 * Encode the private key in a format suitable for
291 * storing it into a file.
292 * @returns encoding of the private key.
293 * The first 4 bytes give the size of the array, as usual.
295 static struct RsaPrivateKeyBinaryEncoded *
296 rsa_encode_key (const struct GNUNET_CRYPTO_RsaPrivateKey *hostkey)
298 struct RsaPrivateKeyBinaryEncoded *retval;
307 if (gcry_pk_testkey (hostkey->sexp))
314 memset (pkv, 0, sizeof (gcry_mpi_t) * 6);
315 rc = key_from_sexp (pkv, hostkey->sexp, "private-key", "nedpqu");
317 rc = key_from_sexp (pkv, hostkey->sexp, "rsa", "nedpqu");
319 rc = key_from_sexp (pkv, hostkey->sexp, "private-key", "nedpq");
321 rc = key_from_sexp (pkv, hostkey->sexp, "rsa", "nedpq");
323 rc = key_from_sexp (pkv, hostkey->sexp, "private-key", "ned");
325 rc = key_from_sexp (pkv, hostkey->sexp, "rsa", "ned");
326 GNUNET_assert (0 == rc);
327 size = sizeof (struct RsaPrivateKeyBinaryEncoded);
328 for (i = 0; i < 6; i++)
332 GNUNET_assert (0 == gcry_mpi_aprint (GCRYMPI_FMT_USG,
333 (unsigned char **) &pbu[i],
343 GNUNET_assert (size < 65536);
344 retval = GNUNET_malloc (size);
345 retval->len = htons (size);
347 retval->sizen = htons (sizes[0]);
348 memcpy (&((char *) (&retval[1]))[i], pbu[0], sizes[0]);
350 retval->sizee = htons (sizes[1]);
351 memcpy (&((char *) (&retval[1]))[i], pbu[1], sizes[1]);
353 retval->sized = htons (sizes[2]);
354 memcpy (&((char *) (&retval[1]))[i], pbu[2], sizes[2]);
357 retval->sizep = htons (sizes[4]);
358 memcpy (&((char *) (&retval[1]))[i], pbu[4], sizes[4]);
360 retval->sizeq = htons (sizes[3]);
361 memcpy (&((char *) (&retval[1]))[i], pbu[3], sizes[3]);
363 retval->sizedmp1 = htons (0);
364 retval->sizedmq1 = htons (0);
365 memcpy (&((char *) (&retval[1]))[i], pbu[5], sizes[5]);
366 for (i = 0; i < 6; i++)
369 gcry_mpi_release (pkv[i]);
377 * Decode the private key from the file-format back
378 * to the "normal", internal format.
380 * @param buf the buffer where the private key data is stored
381 * @param len the length of the data in 'buffer'
383 struct GNUNET_CRYPTO_RsaPrivateKey *
384 GNUNET_CRYPTO_rsa_decode_key (const char *buf, uint16_t len)
386 struct GNUNET_CRYPTO_RsaPrivateKey *ret;
387 const struct RsaPrivateKeyBinaryEncoded *encoding =
388 (const struct RsaPrivateKeyBinaryEncoded *) buf;
390 gcry_mpi_t n, e, d, p, q, u;
396 enc_len = ntohs (encoding->len);
401 size = ntohs (encoding->sizen);
402 rc = gcry_mpi_scan (&n,
404 &((const unsigned char *) (&encoding[1]))[pos],
406 pos += ntohs (encoding->sizen);
409 LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_mpi_scan", rc);
412 size = ntohs (encoding->sizee);
413 rc = gcry_mpi_scan (&e,
415 &((const unsigned char *) (&encoding[1]))[pos],
417 pos += ntohs (encoding->sizee);
420 LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_mpi_scan", rc);
421 gcry_mpi_release (n);
424 size = ntohs (encoding->sized);
425 rc = gcry_mpi_scan (&d,
427 &((const unsigned char *) (&encoding[1]))[pos],
429 pos += ntohs (encoding->sized);
432 LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_mpi_scan", rc);
433 gcry_mpi_release (n);
434 gcry_mpi_release (e);
438 size = ntohs (encoding->sizep);
441 rc = gcry_mpi_scan (&q,
443 &((const unsigned char *) (&encoding[1]))[pos],
445 pos += ntohs (encoding->sizep);
448 LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_mpi_scan", rc);
449 gcry_mpi_release (n);
450 gcry_mpi_release (e);
451 gcry_mpi_release (d);
457 size = ntohs (encoding->sizeq);
460 rc = gcry_mpi_scan (&p,
462 &((const unsigned char *) (&encoding[1]))[pos],
464 pos += ntohs (encoding->sizeq);
467 LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_mpi_scan", rc);
468 gcry_mpi_release (n);
469 gcry_mpi_release (e);
470 gcry_mpi_release (d);
472 gcry_mpi_release (q);
478 pos += ntohs (encoding->sizedmp1);
479 pos += ntohs (encoding->sizedmq1);
481 ntohs (encoding->len) - sizeof (struct RsaPrivateKeyBinaryEncoded) - pos;
484 rc = gcry_mpi_scan (&u,
486 &((const unsigned char *) (&encoding[1]))[pos],
490 LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_mpi_scan", rc);
491 gcry_mpi_release (n);
492 gcry_mpi_release (e);
493 gcry_mpi_release (d);
495 gcry_mpi_release (p);
497 gcry_mpi_release (q);
504 if ((p != NULL) && (q != NULL) && (u != NULL))
506 rc = gcry_sexp_build (&res, &size, /* erroff */
507 "(private-key(rsa(n %m)(e %m)(d %m)(p %m)(q %m)(u %m)))",
512 if ((p != NULL) && (q != NULL))
514 rc = gcry_sexp_build (&res, &size, /* erroff */
515 "(private-key(rsa(n %m)(e %m)(d %m)(p %m)(q %m)))",
520 rc = gcry_sexp_build (&res, &size, /* erroff */
521 "(private-key(rsa(n %m)(e %m)(d %m)))", n, e, d);
524 gcry_mpi_release (n);
525 gcry_mpi_release (e);
526 gcry_mpi_release (d);
528 gcry_mpi_release (p);
530 gcry_mpi_release (q);
532 gcry_mpi_release (u);
535 LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_sexp_build", rc);
537 if (gcry_pk_testkey (res))
539 LOG_GCRY (GNUNET_ERROR_TYPE_ERROR, "gcry_pk_testkey", rc);
543 ret = GNUNET_malloc (sizeof (struct GNUNET_CRYPTO_RsaPrivateKey));
550 * Create a new private key by reading it from a file. If the
551 * files does not exist, create a new key and write it to the
552 * file. Caller must free return value. Note that this function
553 * can not guarantee that another process might not be trying
554 * the same operation on the same file at the same time.
555 * If the contents of the file
556 * are invalid the old file is deleted and a fresh key is
559 * @return new private key, NULL on error (for example,
562 struct GNUNET_CRYPTO_RsaPrivateKey *
563 GNUNET_CRYPTO_rsa_key_create_from_file (const char *filename)
565 struct GNUNET_CRYPTO_RsaPrivateKey *ret;
566 struct RsaPrivateKeyBinaryEncoded *enc;
568 struct GNUNET_DISK_FileHandle *fd;
572 struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded pub;
573 struct GNUNET_PeerIdentity pid;
575 if (GNUNET_SYSERR == GNUNET_DISK_directory_create_for_file (filename))
577 while (GNUNET_YES != GNUNET_DISK_file_test (filename))
579 fd = GNUNET_DISK_file_open (filename,
580 GNUNET_DISK_OPEN_WRITE |
581 GNUNET_DISK_OPEN_CREATE |
582 GNUNET_DISK_OPEN_FAILIFEXISTS,
583 GNUNET_DISK_PERM_USER_READ |
584 GNUNET_DISK_PERM_USER_WRITE);
589 if (GNUNET_YES != GNUNET_DISK_file_test (filename))
591 /* must exist but not be accessible, fail for good! */
592 if (0 != ACCESS (filename, R_OK))
593 GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
596 GNUNET_break (0); /* what is going on!? */
601 GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR, "open", filename);
607 GNUNET_DISK_file_lock (fd, 0,
609 RsaPrivateKeyBinaryEncoded),
616 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
618 ("Could not aquire lock on file `%s': %s...\n"),
619 filename, STRERROR (ec));
622 GNUNET_log (GNUNET_ERROR_TYPE_INFO,
623 _("Creating a new private key. This may take a while.\n"));
624 ret = GNUNET_CRYPTO_rsa_key_create ();
625 GNUNET_assert (ret != NULL);
626 enc = rsa_encode_key (ret);
627 GNUNET_assert (enc != NULL);
628 GNUNET_assert (ntohs (enc->len) ==
629 GNUNET_DISK_file_write (fd, enc, ntohs (enc->len)));
632 GNUNET_DISK_file_sync (fd);
634 GNUNET_DISK_file_unlock (fd, 0,
635 sizeof (struct RsaPrivateKeyBinaryEncoded)))
636 GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, "fcntl", filename);
637 GNUNET_assert (GNUNET_YES == GNUNET_DISK_file_close (fd));
638 GNUNET_CRYPTO_rsa_key_get_public (ret, &pub);
639 GNUNET_CRYPTO_hash (&pub, sizeof (pub), &pid.hashPubKey);
640 GNUNET_log (GNUNET_ERROR_TYPE_INFO,
641 _("I am host `%s'. Stored new private key in `%s'.\n"),
642 GNUNET_i2s (&pid), filename);
645 /* hostkey file exists already, read it! */
646 fd = GNUNET_DISK_file_open (filename, GNUNET_DISK_OPEN_READ,
647 GNUNET_DISK_PERM_NONE);
650 GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR, "open", filename);
657 GNUNET_DISK_file_lock (fd, 0,
658 sizeof (struct RsaPrivateKeyBinaryEncoded),
664 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
665 _("Could not aquire lock on file `%s': %s...\n"),
666 filename, STRERROR (ec));
667 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
669 ("This may be ok if someone is currently generating a hostkey.\n"));
674 if (GNUNET_YES != GNUNET_DISK_file_test (filename))
676 /* eh, what!? File we opened is now gone!? */
677 GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, "stat", filename);
679 GNUNET_DISK_file_unlock (fd, 0,
680 sizeof (struct RsaPrivateKeyBinaryEncoded)))
681 GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, "fcntl", filename);
682 GNUNET_assert (GNUNET_OK == GNUNET_DISK_file_close (fd));
686 if (GNUNET_YES != GNUNET_DISK_file_size (filename, &fs, GNUNET_YES))
688 if (fs < sizeof (struct RsaPrivateKeyBinaryEncoded))
690 /* maybe we got the read lock before the hostkey generating
691 * process had a chance to get the write lock; give it up! */
693 GNUNET_DISK_file_unlock (fd, 0,
694 sizeof (struct RsaPrivateKeyBinaryEncoded)))
695 GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, "fcntl", filename);
698 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
700 ("When trying to read hostkey file `%s' I found %u bytes but I need at least %u.\n"),
701 filename, (unsigned int) fs,
702 (unsigned int) sizeof (struct RsaPrivateKeyBinaryEncoded));
703 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
705 ("This may be ok if someone is currently generating a hostkey.\n"));
707 sleep (2); /* wait a bit longer! */
712 enc = GNUNET_malloc (fs);
713 GNUNET_assert (fs == GNUNET_DISK_file_read (fd, enc, fs));
714 len = ntohs (enc->len);
717 (NULL == (ret = GNUNET_CRYPTO_rsa_decode_key ((char *) enc, len))))
719 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
721 ("File `%s' does not contain a valid private key. Deleting it.\n"),
723 if (0 != UNLINK (filename))
725 GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, "unlink", filename);
730 GNUNET_DISK_file_unlock (fd, 0,
731 sizeof (struct RsaPrivateKeyBinaryEncoded)))
732 GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, "fcntl", filename);
733 GNUNET_assert (GNUNET_YES == GNUNET_DISK_file_close (fd));
736 GNUNET_CRYPTO_rsa_key_get_public (ret, &pub);
737 GNUNET_CRYPTO_hash (&pub, sizeof (pub), &pid.hashPubKey);
738 GNUNET_log (GNUNET_ERROR_TYPE_INFO,
739 _("I am host `%s'. Read private key from `%s'.\n"),
740 GNUNET_i2s (&pid), filename);
747 * Encrypt a block with the public key of another host that uses the
750 * @param block the block to encrypt
751 * @param size the size of block
752 * @param publicKey the encoded public key used to encrypt
753 * @param target where to store the encrypted block
754 * @returns GNUNET_SYSERR on error, GNUNET_OK if ok
757 GNUNET_CRYPTO_rsa_encrypt (const void *block,
760 GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded *publicKey,
761 struct GNUNET_CRYPTO_RsaEncryptedData *target)
765 struct GNUNET_CRYPTO_RsaPrivateKey *pubkey;
771 GNUNET_assert (size <= sizeof (GNUNET_HashCode));
772 pubkey = public2PrivateKey (publicKey);
774 return GNUNET_SYSERR;
777 gcry_mpi_scan (&val, GCRYMPI_FMT_USG, block, isize, &isize));
779 gcry_sexp_build (&data, &erroff,
780 "(data (flags pkcs1)(value %m))", val));
781 gcry_mpi_release (val);
782 GNUNET_assert (0 == gcry_pk_encrypt (&result, data, pubkey->sexp));
783 gcry_sexp_release (data);
784 GNUNET_CRYPTO_rsa_key_free (pubkey);
786 GNUNET_assert (0 == key_from_sexp (&rval, result, "rsa", "a"));
787 gcry_sexp_release (result);
788 isize = sizeof (struct GNUNET_CRYPTO_RsaEncryptedData);
789 GNUNET_assert (0 == gcry_mpi_print (GCRYMPI_FMT_USG,
790 (unsigned char *) target, isize, &isize,
792 gcry_mpi_release (rval);
793 adjust (&target->encoding[0], isize,
794 sizeof (struct GNUNET_CRYPTO_RsaEncryptedData));
799 * Decrypt a given block with the hostkey.
801 * @param key the key with which to decrypt this block
802 * @param block the data to decrypt, encoded as returned by encrypt
803 * @param result pointer to a location where the result can be stored
804 * @param max the maximum number of bits to store for the result, if
805 * the decrypted block is bigger, an error is returned
806 * @return the size of the decrypted block, -1 on error
809 GNUNET_CRYPTO_rsa_decrypt (const struct GNUNET_CRYPTO_RsaPrivateKey * key,
810 const struct GNUNET_CRYPTO_RsaEncryptedData *
811 block, void *result, size_t max)
813 gcry_sexp_t resultsexp;
822 GNUNET_assert (0 == gcry_pk_testkey (key->sexp));
824 size = sizeof (struct GNUNET_CRYPTO_RsaEncryptedData);
825 GNUNET_assert (0 == gcry_mpi_scan (&val,
826 GCRYMPI_FMT_USG, &block->encoding[0],
829 gcry_sexp_build (&data, &erroff,
830 "(enc-val(flags)(rsa(a %m)))", val));
831 gcry_mpi_release (val);
832 GNUNET_assert (0 == gcry_pk_decrypt (&resultsexp, data, key->sexp));
833 gcry_sexp_release (data);
834 /* resultsexp has format "(value %m)" */
835 GNUNET_assert (NULL !=
836 (val = gcry_sexp_nth_mpi (resultsexp, 1, GCRYMPI_FMT_USG)));
837 gcry_sexp_release (resultsexp);
838 tmp = GNUNET_malloc (max + HOSTKEY_LEN / 8);
839 size = max + HOSTKEY_LEN / 8;
840 GNUNET_assert (0 == gcry_mpi_print (GCRYMPI_FMT_USG, tmp, size, &size, val));
841 gcry_mpi_release (val);
843 endp += (size - max);
845 memcpy (result, endp, size);
852 * Sign a given block.
854 * @param key private key to use for the signing
855 * @param purpose what to sign (size, purpose)
856 * @param sig where to write the signature
857 * @return GNUNET_SYSERR on error, GNUNET_OK on success
860 GNUNET_CRYPTO_rsa_sign (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
861 const struct GNUNET_CRYPTO_RsaSignaturePurpose
862 *purpose, struct GNUNET_CRYPTO_RsaSignature *sig)
872 GNUNET_CRYPTO_hash (purpose, ntohl (purpose->size), &hc);
873 #define FORMATSTRING "(4:data(5:flags5:pkcs1)(4:hash6:sha51264:0123456789012345678901234567890123456789012345678901234567890123))"
874 bufSize = strlen (FORMATSTRING) + 1;
875 buff = GNUNET_malloc (bufSize);
876 memcpy (buff, FORMATSTRING, bufSize);
880 ("0123456789012345678901234567890123456789012345678901234567890123))")
881 - 1], &hc, sizeof (GNUNET_HashCode));
882 GNUNET_assert (0 == gcry_sexp_new (&data, buff, bufSize, 0));
884 GNUNET_assert (0 == gcry_pk_sign (&result, data, key->sexp));
885 gcry_sexp_release (data);
886 GNUNET_assert (0 == key_from_sexp (&rval, result, "rsa", "s"));
887 gcry_sexp_release (result);
888 ssize = sizeof (struct GNUNET_CRYPTO_RsaSignature);
889 GNUNET_assert (0 == gcry_mpi_print (GCRYMPI_FMT_USG,
890 (unsigned char *) sig, ssize, &ssize,
892 gcry_mpi_release (rval);
893 adjust (sig->sig, ssize, sizeof (struct GNUNET_CRYPTO_RsaSignature));
901 * @param purpose what is the purpose that the signature should have?
902 * @param validate block to validate (size, purpose, data)
903 * @param sig signature that is being validated
904 * @param publicKey public key of the signer
905 * @returns GNUNET_OK if ok, GNUNET_SYSERR if invalid
908 GNUNET_CRYPTO_rsa_verify (uint32_t purpose,
909 const struct GNUNET_CRYPTO_RsaSignaturePurpose
911 const struct GNUNET_CRYPTO_RsaSignature *sig,
912 const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
919 struct GNUNET_CRYPTO_RsaPrivateKey *hostkey;
926 if (purpose != ntohl (validate->purpose))
927 return GNUNET_SYSERR; /* purpose mismatch */
928 GNUNET_CRYPTO_hash (validate, ntohl (validate->size), &hc);
929 size = sizeof (struct GNUNET_CRYPTO_RsaSignature);
930 GNUNET_assert (0 == gcry_mpi_scan (&val,
932 (const unsigned char *) sig, size, &size));
934 gcry_sexp_build (&sigdata, &erroff, "(sig-val(rsa(s %m)))",
936 gcry_mpi_release (val);
937 bufSize = strlen (FORMATSTRING) + 1;
938 buff = GNUNET_malloc (bufSize);
939 memcpy (buff, FORMATSTRING, bufSize);
940 memcpy (&buff[strlen (FORMATSTRING) -
942 ("0123456789012345678901234567890123456789012345678901234567890123))")],
943 &hc, sizeof (GNUNET_HashCode));
944 GNUNET_assert (0 == gcry_sexp_new (&data, buff, bufSize, 0));
946 hostkey = public2PrivateKey (publicKey);
949 gcry_sexp_release (data);
950 gcry_sexp_release (sigdata);
951 return GNUNET_SYSERR;
953 rc = gcry_pk_verify (sigdata, data, hostkey->sexp);
954 GNUNET_CRYPTO_rsa_key_free (hostkey);
955 gcry_sexp_release (data);
956 gcry_sexp_release (sigdata);
959 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
960 _("RSA signature verification failed at %s:%d: %s\n"),
961 __FILE__, __LINE__, gcry_strerror (rc));
962 return GNUNET_SYSERR;
968 /* end of crypto_rsa.c */