Added RSA/OAEP implementation.

[BearSSL] / src / hash / mgf1.c

diff --git a/src/hash/mgf1.c b/src/hash/mgf1.c
new file mode 100644 (file)
index 0000000..7a23588
--- /dev/null
+++ b/src/hash/mgf1.c
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2018 Thomas Pornin <pornin@bolet.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining 
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be 
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "inner.h"
+
+/* see inner.h */
+void
+br_mgf1_xor(void *data, size_t len,
+       const br_hash_class *dig, const void *seed, size_t seed_len)
+{
+       unsigned char *buf;
+       size_t u, hlen;
+       uint32_t c;
+
+       buf = data;
+       hlen = br_digest_size(dig);
+       for (u = 0, c = 0; u < len; u += hlen, c ++) {
+               br_hash_compat_context hc;
+               unsigned char tmp[64];
+               size_t v;
+
+               hc.vtable = dig;
+               dig->init(&hc.vtable);
+               dig->update(&hc.vtable, seed, seed_len);
+               br_enc32be(tmp, c);
+               dig->update(&hc.vtable, tmp, 4);
+               dig->out(&hc.vtable, tmp);
+               for (v = 0; v < hlen; v ++) {
+                       if ((u + v) >= len) {
+                               break;
+                       }
+                       buf[u + v] ^= tmp[v];
+               }
+       }
+}