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-rw-r--r--src/util/crypto.c83
1 files changed, 75 insertions, 8 deletions
diff --git a/src/util/crypto.c b/src/util/crypto.c
index b75cd8b4..1b829c9f 100644
--- a/src/util/crypto.c
+++ b/src/util/crypto.c
@@ -25,6 +25,19 @@
#include "taler_util.h"
#include <gcrypt.h>
+/**
+ * Should we use the RSA blind signing implementation
+ * from libgnunetutil? The blinding only works
+ * correctly with a current version of libgnunetutil.
+ *
+ * Only applies to blinding and unblinding, but
+ * not to blind signing.
+ *
+ * FIXME: Can we define some macro for this in configure.ac
+ * to detect the version?
+ */
+#define USE_GNUNET_RSA_BLINDING 1
+
/**
* Function called by libgcrypt on serious errors.
@@ -245,11 +258,11 @@ TALER_planchet_prepare (const struct TALER_DenominationPublicKey *dk,
sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey),
c_hash);
if (GNUNET_YES !=
- GNUNET_CRYPTO_rsa_blind (c_hash,
- &ps->blinding_key.bks,
- dk->rsa_public_key,
- &pd->coin_ev,
- &pd->coin_ev_size))
+ TALER_rsa_blind (c_hash,
+ &ps->blinding_key.bks,
+ dk->rsa_public_key,
+ &pd->coin_ev,
+ &pd->coin_ev_size))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
@@ -280,9 +293,9 @@ TALER_planchet_to_coin (const struct TALER_DenominationPublicKey *dk,
{
struct GNUNET_CRYPTO_RsaSignature *sig;
- sig = GNUNET_CRYPTO_rsa_unblind (blind_sig,
- &ps->blinding_key.bks,
- dk->rsa_public_key);
+ sig = TALER_rsa_unblind (blind_sig,
+ &ps->blinding_key.bks,
+ dk->rsa_public_key);
if (GNUNET_OK !=
GNUNET_CRYPTO_rsa_verify (c_hash,
sig,
@@ -381,4 +394,58 @@ TALER_refresh_get_commitment (struct TALER_RefreshCommitmentP *rc,
}
+/**
+ * Blinds the given message with the given blinding key
+ *
+ * @param hash hash of the message to sign
+ * @param bkey the blinding key
+ * @param pkey the public key of the signer
+ * @param[out] buf set to a buffer with the blinded message to be signed
+ * @param[out] buf_size number of bytes stored in @a buf
+ * @return #GNUNET_YES if successful, #GNUNET_NO if RSA key is malicious
+ */
+int
+TALER_rsa_blind (const struct GNUNET_HashCode *hash,
+ const struct GNUNET_CRYPTO_RsaBlindingKeySecret *bks,
+ struct GNUNET_CRYPTO_RsaPublicKey *pkey,
+ void **buf,
+ size_t *buf_size)
+{
+#if USE_GNUNET_RSA_BLINDING
+ return GNUNET_CRYPTO_rsa_blind (hash,
+ bks,
+ pkey,
+ buf,
+ buf_size);
+#else
+# error "FIXME: implement"
+#endif
+}
+
+
+/**
+ * Unblind a blind-signed signature. The signature should have been generated
+ * with #GNUNET_CRYPTO_rsa_sign() using a hash that was blinded with
+ * #GNUNET_CRYPTO_rsa_blind().
+ *
+ * @param sig the signature made on the blinded signature purpose
+ * @param bks the blinding key secret used to blind the signature purpose
+ * @param pkey the public key of the signer
+ * @return unblinded signature on success, NULL if RSA key is bad or malicious.
+ */
+struct GNUNET_CRYPTO_RsaSignature *
+TALER_rsa_unblind (const struct GNUNET_CRYPTO_RsaSignature *sig,
+ const struct GNUNET_CRYPTO_RsaBlindingKeySecret *bks,
+ struct GNUNET_CRYPTO_RsaPublicKey *pkey)
+{
+#if USE_GNUNET_RSA_BLINDING
+ return GNUNET_CRYPTO_rsa_unblind (sig,
+ bks,
+ pkey);
+#else
+# error "FIXME: implement"
+#endif
+}
+
+
/* end of crypto.c */