1 files changed, 64 insertions, 0 deletions
diff --git a/lib/isc/iterated_hash.c b/lib/isc/iterated_hash.c
new file mode 100644
index 0000000..1f95353
--- /dev/null
+++ b/lib/isc/iterated_hash.c
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#include <stdio.h>
+
+#include <openssl/opensslv.h>
+#include <openssl/sha.h>
+
+#include <isc/iterated_hash.h>
+#include <isc/thread.h>
+#include <isc/util.h>
+
+int
+isc_iterated_hash(unsigned char *out, const unsigned int hashalg,
+		  const int iterations, const unsigned char *salt,
+		  const int saltlength, const unsigned char *in,
+		  const int inlength) {
+	REQUIRE(out != NULL);
+
+	int n = 0;
+	size_t len;
+	const unsigned char *buf;
+	SHA_CTX ctx;
+
+	if (hashalg != 1) {
+		return (0);
+	}
+
+	buf = in;
+	len = inlength;
+
+	do {
+		if (SHA1_Init(&ctx) != 1) {
+			return (0);
+		}
+
+		if (SHA1_Update(&ctx, buf, len) != 1) {
+			return (0);
+		}
+
+		if (SHA1_Update(&ctx, salt, saltlength) != 1) {
+			return (0);
+		}
+
+		if (SHA1_Final(out, &ctx) != 1) {
+			return (0);
+		}
+
+		buf = out;
+		len = SHA_DIGEST_LENGTH;
+	} while (n++ < iterations);
+
+	return (SHA_DIGEST_LENGTH);
+}