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-rw-r--r--src/util/crypto.c89
1 files changed, 88 insertions, 1 deletions
diff --git a/src/util/crypto.c b/src/util/crypto.c
index 39df41ceb..158bb9511 100644
--- a/src/util/crypto.c
+++ b/src/util/crypto.c
@@ -1,6 +1,6 @@
/*
This file is part of TALER
- Copyright (C) 2014 Christian Grothoff (and other contributing authors)
+ Copyright (C) 2014, 2015 Christian Grothoff (and other contributing authors)
TALER is free software; you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
@@ -333,4 +333,91 @@ TALER_test_coin_valid (const struct TALER_CoinPublicInfo *coin_public_info)
}
+
+/**
+ * Decrypt the shared @a secret from the information in the
+ * encrypted link secret @e secret_enc using the transfer
+ * private key and the coin's public key.
+ *
+ * @param secret_enc encrypted link secret
+ * @param transfer_priv transfer private key
+ * @param coin_pub coin public key
+ * @param[out] secret set to the shared secret
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
+ */
+int
+TALER_link_decrypt_secret (const struct TALER_EncryptedLinkSecretP *secret_enc,
+ const struct TALER_TransferPrivateKeyP *trans_priv,
+ const union TALER_CoinSpendPublicKeyP *coin_pub,
+ struct TALER_LinkSecretP *secret)
+{
+ struct TALER_TransferSecretP transfer_secret;
+
+ if (GNUNET_OK !=
+ GNUNET_CRYPTO_ecc_ecdh (&trans_priv->ecdhe_priv,
+ &coin_pub->ecdhe_pub,
+ &transfer_secret.key))
+ {
+ GNUNET_break (0);
+ return GNUNET_SYSERR;
+ }
+ if (GNUNET_OK !=
+ TALER_transfer_decrypt (secret_enc,
+ &transfer_secret,
+ secret))
+ {
+ GNUNET_break (0);
+ return GNUNET_SYSERR;
+ }
+ return GNUNET_OK;
+}
+
+
+/**
+ * Encrypt the shared @a secret to generate the encrypted link secret.
+ * Also creates the transfer key.
+ *
+ * @param secret link secret to encrypt
+ * @param coin_pub coin public key
+ * @param transfer_priv[out] set to transfer private key
+ * @param transfer_pub[out] set to transfer public key
+ * @param[out] secret_enc set to the encryptd @a secret
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
+ */
+int
+TALER_link_encrypt_secret (const struct TALER_LinkSecretP *secret,
+ const union TALER_CoinSpendPublicKeyP *coin_pub,
+ struct TALER_TransferPrivateKeyP *trans_priv,
+ struct TALER_TransferPublicKeyP *trans_pub,
+ struct TALER_EncryptedLinkSecretP *secret_enc)
+{
+ struct TALER_TransferSecretP transfer_secret;
+ struct GNUNET_CRYPTO_EcdhePrivateKey *pk;
+
+ pk = GNUNET_CRYPTO_ecdhe_key_create ();
+ if (GNUNET_OK !=
+ GNUNET_CRYPTO_ecc_ecdh (pk,
+ &coin_pub->ecdhe_pub,
+ &transfer_secret.key))
+ {
+ GNUNET_break (0);
+ GNUNET_free (pk);
+ return GNUNET_SYSERR;
+ }
+ if (GNUNET_OK !=
+ TALER_transfer_encrypt (secret,
+ &transfer_secret,
+ secret_enc))
+ {
+ GNUNET_break (0);
+ return GNUNET_SYSERR;
+ }
+ trans_priv->ecdhe_priv = *pk;
+ GNUNET_CRYPTO_ecdhe_key_get_public (pk,
+ &trans_pub->ecdhe_pub);
+ GNUNET_free (pk);
+ return GNUNET_OK;
+}
+
+
/* end of crypto.c */