/* -*-c-*-
*
- * $Id: gcipher.h,v 1.1 1999/12/10 23:16:01 mdw Exp $
+ * $Id: gcipher.h,v 1.5 2004/04/21 00:37:32 mdw Exp $
*
* Generic symmetric cipher interface
*
* (c) 1999 Straylight/Edgeware
*/
-/*----- Licensing notice --------------------------------------------------*
+/*----- Licensing notice --------------------------------------------------*
*
* This file is part of Catacomb.
*
* it under the terms of the GNU Library General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
- *
+ *
* Catacomb 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 Library General Public License for more details.
- *
+ *
* You should have received a copy of the GNU Library General Public
* License along with Catacomb; if not, write to the Free
* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
* MA 02111-1307, USA.
*/
-/*----- Revision history --------------------------------------------------*
- *
- * $Log: gcipher.h,v $
- * Revision 1.1 1999/12/10 23:16:01 mdw
- * Generic interface.
- *
- */
-
#ifndef CATACOMB_GCIPHER_H
#define CATACOMB_GCIPHER_H
#include <stddef.h>
-/*----- Generic symmetric cipher interface --------------------------------*/
+#include <mLib/bits.h>
-typedef struct gccipher_base {
- const char *name; /* Cipher name */
- size_t keysz; /* Preferred key size in bytes */
- size_t blksz; /* Block size or zero if none */
-} gccipher_base;
+/*----- Generic symmetric cipher interface --------------------------------*/
typedef struct gcipher {
const struct gcipher_ops *ops; /* Pointer to cipher operations */
} gcipher;
typedef struct gcipher_ops {
- const struct gccipher_base *b; /* Pointer to basic information */
+ const struct gccipher *c; /* Pointer to cipher class */
void (*encrypt)(gcipher */*c*/, const void */*s*/,
void */*t*/, size_t /*sz*/);
void (*decrypt)(gcipher */*c*/, const void */*s*/,
} gcipher_ops;
typedef struct gccipher {
- gccipher_base b;
+ const char *name; /* Cipher name */
+ const octet *keysz; /* Preferred key size table */
+ size_t blksz; /* Block size or zero if none */
gcipher *(*init)(const void */*k*/, size_t /*sz*/);
} gccipher;
+#define GC_INIT(cc, k, sz) (cc)->init((k), (sz))
+#define GC_CLASS(cc) (cc)->ops->c
+#define GC_ENCRYPT(c, s, t, sz) (c)->ops->encrypt((c), (s), (t), (sz))
+#define GC_DECRYPT(c, s, t, sz) (c)->ops->decrypt((c), (s), (t), (sz))
+#define GC_DESTROY(c) (c)->ops->destroy((c))
+#define GC_SETIV(c, iv) (c)->ops->setiv((c), (iv))
+#define GC_BDRY(c) (c)->ops->bdry((c))
+
+/*----- Key size management -----------------------------------------------*/
+
+/* --- Key size type constants --- *
+ *
+ * A key size limitation is an array of bytes. The first byte describes the
+ * kind of limitation on the key size %$k$%; the rest are argument bytes
+ * %$a_i$%, for %$i \ge 0$%. In all cases, %$a_0$% is the `recommended' key
+ * size.
+ *
+ * * @KSZ_ANY@ means there is no restriction.
+ *
+ * * @KSZ_RANGE@ requires that %$k \ge a_1$%, %$k \equiv 0 \pmod{a_3}$%,
+ * and, if %$a_2 \ne 0$%, %$k \le a_2$%.
+ *
+ * * @KSZ_SET@ requires that %$k \in {\,a_i\,}$%.
+ */
+
+enum {
+ KSZ_ANY, /* Allows any key at all */
+ KSZ_RANGE, /* Allows keys within a range */
+ KSZ_SET /* Allows specific sizes of keys */
+};
+
+/* --- @keysz@ --- *
+ *
+ * Arguments: @size_t sz@ = a proposed key size, or zero
+ * @const octet *ksz@ = pointer to key size table
+ *
+ * Returns: See below.
+ *
+ * Use: Returns a sensible key size. If @sz@ is nonzero, it is
+ * interpreted as an amount (in bytes) of key material which the
+ * caller has available, and the return value is either the
+ * largest allowable key size less than or equal to the caller's
+ * size, or zero if there is no valid key length small enough.
+ * If @sz@ is zero, the function returns a `recommended' key
+ * size.
+ */
+
+extern size_t keysz(size_t /*sz*/, const octet */*ksz*/);
+
+#define KSZ_CHECK(pre, sz) (keysz((sz), pre##_keysz) == (sz))
+#define KSZ_ASSERT(pre, sz) \
+ assert(((void)"Bad key size for " #pre, KSZ_CHECK(pre, sz)))
+
+/*----- Tables ------------------------------------------------------------*/
+
+extern const gccipher *const gciphertab[];
+
+/* --- @gcipher_byname@ --- *
+ *
+ * Arguments: @const char *p@ = pointer to name string
+ *
+ * Returns: The named cipher class, or null.
+ */
+
+extern const gccipher *gcipher_byname(const char */*p*/);
+
/*----- That's all, folks -------------------------------------------------*/
#ifdef __cplusplus