1 files changed, 56 insertions, 0 deletions
diff --git a/src/libdnssec/sign/der.h b/src/libdnssec/sign/der.h
new file mode 100644
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--- /dev/null
+++ b/src/libdnssec/sign/der.h
@@ -0,0 +1,56 @@
+/*  Copyright (C) 2018 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program 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 Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "libdnssec/binary.h"
+
+/*
+ * The ECDSA signatures in DNSSEC are encoded differently than in X.509
+ * (PKCS #1). The cryptographic libraries usually produce the signatures in
+ * X.509 format, which uses Dss-Sig-Value to encapsulate 'r' and 's' values
+ * of the signature.
+ *
+ * This module provides decoding and encoding of this format.
+ *
+ * The 'r' and 's' values are treated as unsigned values: The leading zeroes
+ * are stripped on decoding; an extra leading zero is added on encoding in case
+ * the value starts with a set bit.
+ */
+
+/*!
+ * Decode signature parameters from X.509 ECDSA signature.
+ *
+ * \param[in]  der  X.509 encoded signature.
+ * \param[out] s    Value 's' of the signature, will point to the data in DER.
+ * \param[out] r    Value 'r' of the signature, will point to the data in DER.
+ *
+ * \return Error code, DNSSEC_EOK if successful.
+ */
+int dss_sig_value_decode(const dnssec_binary_t *der,
+			 dnssec_binary_t *r, dnssec_binary_t *s);
+
+/*!
+ * Encode signature parameters from X.509 ECDSA signature.
+ *
+ * \param[in]  s    Value 's' of the signature.
+ * \param[in]  r    Value 'r' of the signature.
+ * \param[out] der  X.509 signature, the content will be allocated.
+ *
+ * \return Error code, DNSSEC_EOK if successful.
+ */
+int dss_sig_value_encode(const dnssec_binary_t *r, const dnssec_binary_t *s,
+			 dnssec_binary_t *der);