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18 * @file util/crypto_rsa.c
19 * @brief Chaum-style Blind signatures based on RSA
20 * @author Sree Harsha Totakura <sreeharsha@totakura.in>
21 * @author Christian Grothoff
22 * @author Jeffrey Burdges <burdges@gnunet.org>
26 #include "gnunet_crypto_lib.h"
28 #define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)
32 * The private information of an RSA key pair.
34 struct GNUNET_CRYPTO_RsaPrivateKey
37 * Libgcrypt S-expression for the RSA private key.
44 * The public information of an RSA key pair.
46 struct GNUNET_CRYPTO_RsaPublicKey
49 * Libgcrypt S-expression for the RSA public key.
56 * @brief an RSA signature
58 struct GNUNET_CRYPTO_RsaSignature
61 * Libgcrypt S-expression for the RSA signature.
68 * @brief RSA blinding key
73 * Random value used for blinding.
80 * Extract values from an S-expression.
82 * @param array where to store the result(s)
83 * @param sexp S-expression to parse
84 * @param topname top-level name in the S-expression that is of interest
85 * @param elems names of the elements to extract
86 * @return 0 on success
89 key_from_sexp (gcry_mpi_t *array,
100 if (! (list = gcry_sexp_find_token (sexp, topname, 0)))
102 l2 = gcry_sexp_cadr (list);
103 gcry_sexp_release (list);
108 for (s = elems; *s; s++, idx++)
110 if (! (l2 = gcry_sexp_find_token (list, s, 1)))
112 for (i = 0; i < idx; i++)
114 gcry_free (array[i]);
117 gcry_sexp_release (list);
118 return 3; /* required parameter not found */
120 array[idx] = gcry_sexp_nth_mpi (l2, 1, GCRYMPI_FMT_USG);
121 gcry_sexp_release (l2);
124 for (i = 0; i < idx; i++)
126 gcry_free (array[i]);
129 gcry_sexp_release (list);
130 return 4; /* required parameter is invalid */
133 gcry_sexp_release (list);
139 * Create a new private key. Caller must free return value.
141 * @param len length of the key in bits (i.e. 2048)
142 * @return fresh private key
144 struct GNUNET_CRYPTO_RsaPrivateKey *
145 GNUNET_CRYPTO_rsa_private_key_create (unsigned int len)
147 struct GNUNET_CRYPTO_RsaPrivateKey *ret;
149 gcry_sexp_t s_keyparam;
152 gcry_sexp_build (&s_keyparam,
154 "(genkey(rsa(nbits %d)))",
157 gcry_pk_genkey (&s_key,
159 gcry_sexp_release (s_keyparam);
162 gcry_pk_testkey (s_key));
164 ret = GNUNET_new (struct GNUNET_CRYPTO_RsaPrivateKey);
171 * Free memory occupied by the private key.
173 * @param key pointer to the memory to free
176 GNUNET_CRYPTO_rsa_private_key_free (struct GNUNET_CRYPTO_RsaPrivateKey *key)
178 gcry_sexp_release (key->sexp);
184 * Encode the private key in a format suitable for
185 * storing it into a file.
187 * @param key the private key
188 * @param[out] buffer set to a buffer with the encoded key
189 * @return size of memory allocated in @a buffer
192 GNUNET_CRYPTO_rsa_private_key_encode (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
198 n = gcry_sexp_sprint (key->sexp,
199 GCRYSEXP_FMT_DEFAULT,
202 b = GNUNET_malloc (n);
203 GNUNET_assert ((n - 1) == /* since the last byte is \0 */
204 gcry_sexp_sprint (key->sexp,
205 GCRYSEXP_FMT_DEFAULT,
214 * Decode the private key from the data-format back
215 * to the "normal", internal format.
217 * @param buf the buffer where the private key data is stored
218 * @param len the length of the data in @a buf
219 * @return NULL on error
221 struct GNUNET_CRYPTO_RsaPrivateKey *
222 GNUNET_CRYPTO_rsa_private_key_decode (const char *buf,
225 struct GNUNET_CRYPTO_RsaPrivateKey *key;
226 key = GNUNET_new (struct GNUNET_CRYPTO_RsaPrivateKey);
228 gcry_sexp_new (&key->sexp,
233 LOG (GNUNET_ERROR_TYPE_WARNING,
234 "Decoded private key is not valid\n");
238 if (0 != gcry_pk_testkey (key->sexp))
240 LOG (GNUNET_ERROR_TYPE_WARNING,
241 "Decoded private key is not valid\n");
242 GNUNET_CRYPTO_rsa_private_key_free (key);
250 * Extract the public key of the given private key.
252 * @param priv the private key
253 * @retur NULL on error, otherwise the public key
255 struct GNUNET_CRYPTO_RsaPublicKey *
256 GNUNET_CRYPTO_rsa_private_key_get_public (const struct GNUNET_CRYPTO_RsaPrivateKey *priv)
258 struct GNUNET_CRYPTO_RsaPublicKey *pub;
263 rc = key_from_sexp (ne, priv->sexp, "public-key", "ne");
265 rc = key_from_sexp (ne, priv->sexp, "private-key", "ne");
267 rc = key_from_sexp (ne, priv->sexp, "rsa", "ne");
273 rc = gcry_sexp_build (&result,
275 "(public-key(rsa(n %m)(e %m)))",
278 gcry_mpi_release (ne[0]);
279 gcry_mpi_release (ne[1]);
280 pub = GNUNET_new (struct GNUNET_CRYPTO_RsaPublicKey);
287 * Free memory occupied by the public key.
289 * @param key pointer to the memory to free
292 GNUNET_CRYPTO_rsa_public_key_free (struct GNUNET_CRYPTO_RsaPublicKey *key)
294 gcry_sexp_release (key->sexp);
300 * Encode the public key in a format suitable for
301 * storing it into a file.
303 * @param key the private key
304 * @param[out] buffer set to a buffer with the encoded key
305 * @return size of memory allocated in @a buffer
308 GNUNET_CRYPTO_rsa_public_key_encode (const struct GNUNET_CRYPTO_RsaPublicKey *key,
314 n = gcry_sexp_sprint (key->sexp,
315 GCRYSEXP_FMT_ADVANCED,
318 b = GNUNET_malloc (n);
319 GNUNET_assert ((n -1) == /* since the last byte is \0 */
320 gcry_sexp_sprint (key->sexp,
321 GCRYSEXP_FMT_ADVANCED,
330 * Compute hash over the public key.
332 * @param key public key to hash
333 * @param hc where to store the hash code
336 GNUNET_CRYPTO_rsa_public_key_hash (const struct GNUNET_CRYPTO_RsaPublicKey *key,
337 struct GNUNET_HashCode *hc)
342 buf_size = GNUNET_CRYPTO_rsa_public_key_encode (key,
344 GNUNET_CRYPTO_hash (buf,
352 * Decode the public key from the data-format back
353 * to the "normal", internal format.
355 * @param buf the buffer where the public key data is stored
356 * @param len the length of the data in @a buf
357 * @return NULL on error
359 struct GNUNET_CRYPTO_RsaPublicKey *
360 GNUNET_CRYPTO_rsa_public_key_decode (const char *buf,
363 struct GNUNET_CRYPTO_RsaPublicKey *key;
367 key = GNUNET_new (struct GNUNET_CRYPTO_RsaPublicKey);
369 gcry_sexp_new (&key->sexp,
378 /* verify that this is an RSA public key */
379 ret = key_from_sexp (&n, key->sexp, "public-key", "n");
381 ret = key_from_sexp (&n, key->sexp, "rsa", "n");
384 /* this is no public RSA key */
386 gcry_sexp_release (key->sexp);
390 gcry_mpi_release (n);
396 * Create a blinding key
398 * @param len length of the key in bits (i.e. 2048)
399 * @param bks pre-secret to use to derive the blinding key
400 * @return the newly created blinding key
402 static struct RsaBlindingKey *
403 rsa_blinding_key_derive (const struct GNUNET_CRYPTO_RsaPublicKey *pkey,
404 const struct GNUNET_CRYPTO_RsaBlindingKeySecret *bks)
406 char *xts = "Blinding KDF extrator HMAC key"; /* Trusts bks' randomness more */
407 struct RsaBlindingKey *blind;
410 blind = GNUNET_new (struct RsaBlindingKey);
412 /* Extract the composite n from the RSA public key */
413 GNUNET_assert( 0 == key_from_sexp (&n, pkey->sexp, "rsa", "n") );
414 GNUNET_assert( 0 == gcry_mpi_get_flag(n, GCRYMPI_FLAG_OPAQUE) );
416 GNUNET_CRYPTO_kdf_mod_mpi (&blind->r,
426 We originally added GNUNET_CRYPTO_kdf_mod_mpi for the benifit of the
429 There was previously a call to GNUNET_CRYPTO_kdf in
430 bkey = rsa_blinding_key_derive (len, bks);
431 that gives exactly len bits where
432 len = GNUNET_CRYPTO_rsa_public_key_len (pkey);
434 Now r = 2^(len-1)/pkey.n is the probability that a set high bit being
435 okay, meaning bkey < pkey.n. It follows that (1-r)/2 of the time bkey >
436 pkey.n making the effective bkey be
437 bkey mod pkey.n = bkey - pkey.n
438 so the effective bkey has its high bit set with probability r/2.
440 We expect r to be close to 1/2 if the exchange is honest, but the
441 exchange can choose r otherwise.
443 In blind signing, the exchange sees
444 B = bkey * S mod pkey.n
445 On deposit, the exchange sees S so they can compute bkey' = B/S mod
446 pkey.n for all B they recorded to see if bkey' has it's high bit set.
447 Also, note the exchange can compute 1/S efficiently since they know the
450 I suppose that happens with probability r/(1+r) if its the wrong B, not
451 completely sure. If otoh we've the right B, then we've the probability
452 r/2 of a set high bit in the effective bkey.
454 Interestingly, r^2-r has a maximum at the default r=1/2 anyways, giving
455 the wrong and right probabilities 1/3 and 1/4, respectively.
457 I feared this gives the exchange a meaningful fraction of a bit of
458 information per coin involved in the transaction. It sounds damaging if
459 numerous coins were involved. And it could run across transactions in
462 We fixed this by using a more uniform deterministic pseudo-random number
463 generator for blinding factors. I do not believe this to be a problem
464 for the rsa_full_domain_hash routine, but better safe than sorry.
469 * Compare the values of two signatures.
471 * @param s1 one signature
472 * @param s2 the other signature
473 * @return 0 if the two are equal
476 GNUNET_CRYPTO_rsa_signature_cmp (struct GNUNET_CRYPTO_RsaSignature *s1,
477 struct GNUNET_CRYPTO_RsaSignature *s2)
485 z1 = GNUNET_CRYPTO_rsa_signature_encode (s1,
487 z2 = GNUNET_CRYPTO_rsa_signature_encode (s2,
502 * Compare the values of two public keys.
504 * @param p1 one public key
505 * @param p2 the other public key
506 * @return 0 if the two are equal
509 GNUNET_CRYPTO_rsa_public_key_cmp (struct GNUNET_CRYPTO_RsaPublicKey *p1,
510 struct GNUNET_CRYPTO_RsaPublicKey *p2)
518 z1 = GNUNET_CRYPTO_rsa_public_key_encode (p1,
520 z2 = GNUNET_CRYPTO_rsa_public_key_encode (p2,
535 * Compare the values of two private keys.
537 * @param p1 one private key
538 * @param p2 the other private key
539 * @return 0 if the two are equal
542 GNUNET_CRYPTO_rsa_private_key_cmp (struct GNUNET_CRYPTO_RsaPrivateKey *p1,
543 struct GNUNET_CRYPTO_RsaPrivateKey *p2)
551 z1 = GNUNET_CRYPTO_rsa_private_key_encode (p1,
553 z2 = GNUNET_CRYPTO_rsa_private_key_encode (p2,
568 * Obtain the length of the RSA key in bits.
570 * @param key the public key to introspect
571 * @return length of the key in bits
574 GNUNET_CRYPTO_rsa_public_key_len (const struct GNUNET_CRYPTO_RsaPublicKey *key)
579 if (0 != key_from_sexp (&n, key->sexp, "rsa", "n"))
580 { /* Not an RSA public key */
584 rval = gcry_mpi_get_nbits (n);
585 gcry_mpi_release (n);
591 * Destroy a blinding key
593 * @param bkey the blinding key to destroy
596 rsa_blinding_key_free (struct RsaBlindingKey *bkey)
598 gcry_mpi_release (bkey->r);
604 * Print an MPI to a newly created buffer
606 * @param v MPI to print.
607 * @param[out] newly allocated buffer containing the result
608 * @return number of bytes stored in @a buffer
611 numeric_mpi_alloc_n_print (gcry_mpi_t v,
618 gcry_mpi_print (GCRYMPI_FMT_USG,
623 b = GNUNET_malloc (n);
625 gcry_mpi_print (GCRYMPI_FMT_USG,
636 * Computes a full domain hash seeded by the given public key.
637 * This gives a measure of provable security to the Taler exchange
638 * against one-more forgery attacks. See:
639 * https://eprint.iacr.org/2001/002.pdf
640 * http://www.di.ens.fr/~pointche/Documents/Papers/2001_fcA.pdf
642 * @param[out] r MPI value set to the FDH
643 * @param hash initial hash of the message to sign
644 * @param pkey the public key of the signer
645 * @param rsize If not NULL, the number of bytes actually stored in buffer
648 rsa_full_domain_hash (gcry_mpi_t *r,
649 const struct GNUNET_HashCode *hash,
650 const struct GNUNET_CRYPTO_RsaPublicKey *pkey)
656 /* Extract the composite n from the RSA public key */
657 GNUNET_assert( 0 == key_from_sexp (&n, pkey->sexp, "rsa", "n") );
658 GNUNET_assert( 0 == gcry_mpi_get_flag(n, GCRYMPI_FLAG_OPAQUE) );
660 /* We key with the public denomination key as a homage to RSA-PSS by *
661 * Mihir Bellare and Phillip Rogaway. Doing this lowers the degree *
662 * of the hypothetical polyomial-time attack on RSA-KTI created by a *
663 * polynomial-time one-more forgary attack. Yey seeding! */
664 xts_len = GNUNET_CRYPTO_rsa_public_key_encode (pkey, &xts);
666 GNUNET_CRYPTO_kdf_mod_mpi (r,
677 * Blinds the given message with the given blinding key
679 * @param hash hash of the message to sign
680 * @param bkey the blinding key
681 * @param pkey the public key of the signer
682 * @param[out] buffer set to a buffer with the blinded message to be signed
683 * @return number of bytes stored in @a buffer
686 GNUNET_CRYPTO_rsa_blind (const struct GNUNET_HashCode *hash,
687 const struct GNUNET_CRYPTO_RsaBlindingKeySecret *bks,
688 struct GNUNET_CRYPTO_RsaPublicKey *pkey,
691 struct RsaBlindingKey *bkey;
699 ret = key_from_sexp (ne, pkey->sexp, "public-key", "ne");
701 ret = key_from_sexp (ne, pkey->sexp, "rsa", "ne");
709 rsa_full_domain_hash (&data, hash, pkey);
710 bkey = rsa_blinding_key_derive (pkey,
712 r_e = gcry_mpi_new (0);
717 data_r_e = gcry_mpi_new (0);
718 gcry_mpi_mulm (data_r_e,
722 gcry_mpi_release (data);
723 gcry_mpi_release (ne[0]);
724 gcry_mpi_release (ne[1]);
725 gcry_mpi_release (r_e);
726 rsa_blinding_key_free (bkey);
728 n = numeric_mpi_alloc_n_print (data_r_e, buffer);
729 gcry_mpi_release (data_r_e);
735 * Convert an MPI to an S-expression suitable for signature operations.
737 * @param value pointer to the data to convert
738 * @return converted s-expression
741 mpi_to_sexp (gcry_mpi_t value)
743 gcry_sexp_t data = NULL;
746 gcry_sexp_build (&data,
748 "(data (flags raw) (value %M))",
755 * Sign the given MPI.
757 * @param key private key to use for the signing
758 * @param value the MPI to sign
759 * @return NULL on error, signature on success
761 static struct GNUNET_CRYPTO_RsaSignature *
762 rsa_sign_mpi (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
765 struct GNUNET_CRYPTO_RsaSignature *sig;
766 struct GNUNET_CRYPTO_RsaPublicKey *public_key;
771 data = mpi_to_sexp (value);
774 (rc = gcry_pk_sign (&result,
778 LOG (GNUNET_ERROR_TYPE_WARNING,
779 _("RSA signing failed at %s:%d: %s\n"),
787 /* verify signature (guards against Lenstra's attack with fault injection...) */
788 public_key = GNUNET_CRYPTO_rsa_private_key_get_public (key);
790 gcry_pk_verify (result,
795 GNUNET_CRYPTO_rsa_public_key_free (public_key);
796 gcry_sexp_release (data);
797 gcry_sexp_release (result);
800 GNUNET_CRYPTO_rsa_public_key_free (public_key);
802 /* return signature */
803 gcry_sexp_release (data);
804 sig = GNUNET_new (struct GNUNET_CRYPTO_RsaSignature);
811 * Sign a blinded value, which must be a full domain hash of a message.
813 * @param key private key to use for the signing
814 * @param msg the message to sign
815 * @param msg_len number of bytes in @a msg to sign
816 * @return NULL on error, signature on success
818 struct GNUNET_CRYPTO_RsaSignature *
819 GNUNET_CRYPTO_rsa_sign_blinded (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
824 struct GNUNET_CRYPTO_RsaSignature *sig;
833 sig = rsa_sign_mpi (key, v);
834 gcry_mpi_release (v);
840 * Create and sign a full domain hash of a message.
842 * @param key private key to use for the signing
843 * @param hash the hash of the message to sign
844 * @return NULL on error, signature on success
846 struct GNUNET_CRYPTO_RsaSignature *
847 GNUNET_CRYPTO_rsa_sign_fdh (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
848 const struct GNUNET_HashCode *hash)
850 struct GNUNET_CRYPTO_RsaPublicKey *pkey;
852 struct GNUNET_CRYPTO_RsaSignature *sig;
854 pkey = GNUNET_CRYPTO_rsa_private_key_get_public (key);
855 rsa_full_domain_hash (&v, hash, pkey);
856 GNUNET_CRYPTO_rsa_public_key_free (pkey);
858 sig = rsa_sign_mpi (key, v);
859 gcry_mpi_release (v);
866 * Free memory occupied by signature.
868 * @param sig memory to freee
871 GNUNET_CRYPTO_rsa_signature_free (struct GNUNET_CRYPTO_RsaSignature *sig)
873 gcry_sexp_release (sig->sexp);
879 * Encode the given signature in a format suitable for storing it into a file.
881 * @param sig the signature
882 * @param[out] buffer set to a buffer with the encoded key
883 * @return size of memory allocated in @a buffer
886 GNUNET_CRYPTO_rsa_signature_encode (const struct GNUNET_CRYPTO_RsaSignature *sig,
892 n = gcry_sexp_sprint (sig->sexp,
893 GCRYSEXP_FMT_ADVANCED,
896 b = GNUNET_malloc (n);
897 GNUNET_assert ((n - 1) == /* since the last byte is \0 */
898 gcry_sexp_sprint (sig->sexp,
899 GCRYSEXP_FMT_ADVANCED,
908 * Decode the signature from the data-format back to the "normal", internal
911 * @param buf the buffer where the public key data is stored
912 * @param len the length of the data in @a buf
913 * @return NULL on error
915 struct GNUNET_CRYPTO_RsaSignature *
916 GNUNET_CRYPTO_rsa_signature_decode (const char *buf,
919 struct GNUNET_CRYPTO_RsaSignature *sig;
923 sig = GNUNET_new (struct GNUNET_CRYPTO_RsaSignature);
925 gcry_sexp_new (&sig->sexp,
934 /* verify that this is an RSA signature */
935 ret = key_from_sexp (&s, sig->sexp, "sig-val", "s");
937 ret = key_from_sexp (&s, sig->sexp, "rsa", "s");
940 /* this is no RSA Signature */
942 gcry_sexp_release (sig->sexp);
946 gcry_mpi_release (s);
952 * Duplicate the given public key
954 * @param key the public key to duplicate
955 * @return the duplicate key; NULL upon error
957 struct GNUNET_CRYPTO_RsaPublicKey *
958 GNUNET_CRYPTO_rsa_public_key_dup (const struct GNUNET_CRYPTO_RsaPublicKey *key)
960 struct GNUNET_CRYPTO_RsaPublicKey *dup;
961 gcry_sexp_t dup_sexp;
964 /* check if we really are exporting a public key */
965 dup_sexp = gcry_sexp_find_token (key->sexp, "public-key", 0);
966 GNUNET_assert (NULL != dup_sexp);
967 gcry_sexp_release (dup_sexp);
969 GNUNET_assert (0 == gcry_sexp_build (&dup_sexp, &erroff, "%S", key->sexp));
970 dup = GNUNET_new (struct GNUNET_CRYPTO_RsaPublicKey);
971 dup->sexp = dup_sexp;
977 * Unblind a blind-signed signature. The signature should have been generated
978 * with #GNUNET_CRYPTO_rsa_sign() using a hash that was blinded with
979 * #GNUNET_CRYPTO_rsa_blind().
981 * @param sig the signature made on the blinded signature purpose
982 * @param bks the blinding key secret used to blind the signature purpose
983 * @param pkey the public key of the signer
984 * @return unblinded signature on success, NULL on error
986 struct GNUNET_CRYPTO_RsaSignature *
987 GNUNET_CRYPTO_rsa_unblind (struct GNUNET_CRYPTO_RsaSignature *sig,
988 const struct GNUNET_CRYPTO_RsaBlindingKeySecret *bks,
989 struct GNUNET_CRYPTO_RsaPublicKey *pkey)
991 struct RsaBlindingKey *bkey;
997 struct GNUNET_CRYPTO_RsaSignature *sret;
999 ret = key_from_sexp (&n, pkey->sexp, "public-key", "n");
1001 ret = key_from_sexp (&n, pkey->sexp, "rsa", "n");
1004 GNUNET_break_op (0);
1007 ret = key_from_sexp (&s, sig->sexp, "sig-val", "s");
1009 ret = key_from_sexp (&s, sig->sexp, "rsa", "s");
1012 gcry_mpi_release (n);
1013 GNUNET_break_op (0);
1016 bkey = rsa_blinding_key_derive (pkey,
1019 r_inv = gcry_mpi_new (0);
1021 gcry_mpi_invm (r_inv,
1025 GNUNET_break_op (0);
1026 gcry_mpi_release (n);
1027 gcry_mpi_release (r_inv);
1028 gcry_mpi_release (s);
1029 rsa_blinding_key_free (bkey);
1032 ubsig = gcry_mpi_new (0);
1033 gcry_mpi_mulm (ubsig, s, r_inv, n);
1034 gcry_mpi_release (n);
1035 gcry_mpi_release (r_inv);
1036 gcry_mpi_release (s);
1037 rsa_blinding_key_free (bkey);
1039 sret = GNUNET_new (struct GNUNET_CRYPTO_RsaSignature);
1041 gcry_sexp_build (&sret->sexp,
1043 "(sig-val (rsa (s %M)))",
1045 gcry_mpi_release (ubsig);
1051 * Verify whether the given hash corresponds to the given signature and the
1052 * signature is valid with respect to the given public key.
1054 * @param hash hash of the message to verify to match the @a sig
1055 * @param sig signature that is being validated
1056 * @param pkey public key of the signer
1057 * @returns #GNUNET_OK if ok, #GNUNET_SYSERR if invalid
1060 GNUNET_CRYPTO_rsa_verify (const struct GNUNET_HashCode *hash,
1061 const struct GNUNET_CRYPTO_RsaSignature *sig,
1062 const struct GNUNET_CRYPTO_RsaPublicKey *pkey)
1068 rsa_full_domain_hash (&r, hash, pkey);
1069 data = mpi_to_sexp(r);
1070 gcry_mpi_release (r);
1072 rc = gcry_pk_verify (sig->sexp,
1075 gcry_sexp_release (data);
1078 LOG (GNUNET_ERROR_TYPE_WARNING,
1079 _("RSA signature verification failed at %s:%d: %s\n"),
1082 gcry_strerror (rc));
1083 return GNUNET_SYSERR;
1090 * Duplicate the given private key
1092 * @param key the private key to duplicate
1093 * @return the duplicate key; NULL upon error
1095 struct GNUNET_CRYPTO_RsaPrivateKey *
1096 GNUNET_CRYPTO_rsa_private_key_dup (const struct GNUNET_CRYPTO_RsaPrivateKey *key)
1098 struct GNUNET_CRYPTO_RsaPrivateKey *dup;
1099 gcry_sexp_t dup_sexp;
1102 /* check if we really are exporting a private key */
1103 dup_sexp = gcry_sexp_find_token (key->sexp, "private-key", 0);
1104 GNUNET_assert (NULL != dup_sexp);
1105 gcry_sexp_release (dup_sexp);
1107 GNUNET_assert (0 == gcry_sexp_build (&dup_sexp, &erroff, "%S", key->sexp));
1108 dup = GNUNET_new (struct GNUNET_CRYPTO_RsaPrivateKey);
1109 dup->sexp = dup_sexp;
1115 * Duplicate the given private key
1117 * @param key the private key to duplicate
1118 * @return the duplicate key; NULL upon error
1120 struct GNUNET_CRYPTO_RsaSignature *
1121 GNUNET_CRYPTO_rsa_signature_dup (const struct GNUNET_CRYPTO_RsaSignature *sig)
1123 struct GNUNET_CRYPTO_RsaSignature *dup;
1124 gcry_sexp_t dup_sexp;
1129 /* verify that this is an RSA signature */
1130 ret = key_from_sexp (&s, sig->sexp, "sig-val", "s");
1132 ret = key_from_sexp (&s, sig->sexp, "rsa", "s");
1133 GNUNET_assert (0 == ret);
1134 gcry_mpi_release (s);
1136 GNUNET_assert (0 == gcry_sexp_build (&dup_sexp, &erroff, "%S", sig->sexp));
1137 dup = GNUNET_new (struct GNUNET_CRYPTO_RsaSignature);
1138 dup->sexp = dup_sexp;
1143 /* end of util/rsa.c */