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User/lib/cifra/prp.h

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+/*
+ * cifra - embedded cryptography library
+ * Written in 2014 by Joseph Birr-Pixton <jpixton@gmail.com>
+ *
+ * To the extent possible under law, the author(s) have dedicated all
+ * copyright and related and neighboring rights to this software to the
+ * public domain worldwide. This software is distributed without any
+ * warranty.
+ *
+ * You should have received a copy of the CC0 Public Domain Dedication
+ * along with this software. If not, see
+ * <http://creativecommons.org/publicdomain/zero/1.0/>.
+ */
+
+#ifndef PRP_H
+#define PRP_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+/**
+ * General block cipher description
+ * ================================
+ * This allows us to implement block cipher modes which can work
+ * with different block ciphers.
+ */
+
+/* .. c:type:: cf_prp_block
+ * Block processing function type.
+ *
+ * The `in` and `out` blocks may alias.
+ *
+ * :rtype: void
+ * :param ctx: block cipher-specific context object.
+ * :param in: input block.
+ * :param out: output block.
+ */
+typedef void (*cf_prp_block)(void *ctx, const uint8_t *in, uint8_t *out);
+
+/* .. c:type:: cf_prp
+ * Describes an PRP in a general way.
+ *
+ * .. c:member:: cf_prp.blocksz
+ * Block size in bytes. Must be no more than :c:macro:`CF_MAXBLOCK`.
+ *
+ * .. c:member:: cf_prp.encrypt
+ * Block encryption function.
+ *
+ * .. c:member:: cf_prp.decrypt
+ * Block decryption function.
+ */
+typedef struct
+{
+  size_t blocksz;
+  cf_prp_block encrypt;
+  cf_prp_block decrypt;
+} cf_prp;
+
+/* .. c:macro:: CF_MAXBLOCK
+ * The maximum block cipher blocksize we support, in bytes.
+ */
+#define CF_MAXBLOCK 16
+
+#endif