--- /dev/null
+/* -*-c-*-
+ *
+ * $Id: dsa.h,v 1.1 1999/11/19 19:28:00 mdw Exp $
+ *
+ * Digital Signature Algorithm
+ *
+ * (c) 1999 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of Catacomb.
+ *
+ * Catacomb is free software; you can redistribute it and/or modify
+ * 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: dsa.h,v $
+ * Revision 1.1 1999/11/19 19:28:00 mdw
+ * Implementation of the Digital Signature Algorithm.
+ *
+ */
+
+#ifndef DSA_H
+#define DSA_H
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+/*----- Notes on the Digital Signature Algorithm --------------------------*
+ *
+ * The Digital Signature Algorithm was designed by the NSA for US Government
+ * use. It's defined in FIPS 186-1. Whether it's covered by patents is
+ * under dispute, although it looks relatively clear. It produces compact
+ * signatures, and is relatively easy to compute. It seems strong, if
+ * appropriate parameters are chosen.
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#ifndef MP_H
+# include "mp.h"
+#endif
+
+/*----- Event codes -------------------------------------------------------*/
+
+enum {
+ DSAEV_OK, /* Everything is fine */
+
+ DSAEV_FAILQ, /* @q@ failed primality test */
+ DSAEV_PASSQ, /* @q@ passeed one iteration */
+ DSAEV_GOODQ, /* Found good prime @q@ */
+
+ DSAEV_TRYP, /* Try prospective @p@ */
+ DSAEV_FAILP, /* @p@ failed primality test */
+ DSAEV_PASSP, /* @p@ passed one iteration */
+ DSAEV_GOODP, /* @p@ accepted as being prime */
+
+ DSAEV_TRYH, /* Try prospective @h@ */
+ DSAEV_FAILH, /* @h@ failed */
+ DSAEV_GOODG /* @g@ accepted as a generator */
+};
+
+/*----- Data structures ---------------------------------------------------*/
+
+/* --- DSA parameter structure --- *
+ *
+ * These parameters can, and probably should, be shared among a group of
+ * users.
+ */
+
+typedef struct dsa_param {
+ mp *p, *q; /* Prime numbers %$p$% and %$q$% */
+ mp *g; /* Generates order-%$q$% subgroup */
+} dsa_param;
+
+/* --- DSA signature structure --- *
+ *
+ * This is the recommended structure for a DSA signature. The actual signing
+ * function can cope with arbitrary-sized objects given appropriate
+ * parameters, however.
+ */
+
+#define DSA_SIGLEN 20
+
+typedef struct dsa_sig {
+ octet r[DSA_SIGLEN]; /* 160-bit @r@ value */
+ octet s[DSA_SIGLEN]; /* 160-bit @s@ value */
+} dsa_sig;
+
+/*----- Functions provided ------------------------------------------------*/
+
+/* --- @dsa_seed@ --- *
+ *
+ * Arguments: @dsa_param *dp@ = where to store parameters
+ * @unsigned l@ = bitlength of @p@ in bits
+ * @const void *k@ = pointer to key material
+ * @size_t sz@ = size of key material
+ * @void (*proc)(int ev, mp *m, void *p)@ = event procedure
+ * @void *p@ = argument for event procedure
+ *
+ * Returns: Zero if all went well, nonzero if key material was
+ * unsuitable (one of the @DSAEV@ codes).
+ *
+ * Use: Generates the DSA shared parameters from a given seed value.
+ * This can take quite a long time. The size of @p@ in bits is
+ * %$l = 512 + 64l'$%. The DSA standard, FIPS 186, only allows
+ * %$0 \le l' \le 8$%. This implementation has no such limit,
+ * although @l@ must be a multiple of 8.
+ *
+ * The event procedure is informed of various happenings during
+ * generation. It is passed an event code describing what
+ * happened, and a multiprecision number which pertains to the
+ * event code.
+ */
+
+extern int dsa_seed(dsa_param */*dp*/, unsigned /*l*/,
+ const void */*k*/, size_t /*sz*/,
+ void (*proc)(int /*ev*/, mp */*m*/, void */*p*/),
+ void */*p*/);
+
+/* --- @dsa_mksig@ --- *
+ *
+ * Arguments: @const dsa_param *dp@ = pointer to DSA parameters
+ * @const mp *a@ = secret signing key
+ * @const mp *m@ = message to be signed
+ * @const mp *k@ = random data
+ * @mp **rr, **ss@ = where to put output parameters
+ *
+ * Returns: ---
+ *
+ * Use: Computes a DSA signature of a message.
+ */
+
+extern void dsa_mksig(const dsa_param */*dp*/, const mp */*a*/,
+ const mp */*m*/, const mp */*k*/,
+ mp **/*rr*/, mp **/*ss*/);
+
+/* --- @dsa_sign@ --- *
+ *
+ * Arguments: @dsa_param *dp@ = pointer to DSA parameters
+ * @mp *a@ = pointer to secret signing key
+ * @const void *m@ = pointer to message
+ * @size_t msz@ = size of the message
+ * @const void *k@ = secret random data for securing signature
+ * @size_t ksz@ = size of secret data
+ * @void *r@ = pointer to output space for @r@
+ * @size_t rsz@ = size of output space for @r@
+ * @void *s@ = pointer to output space for @s@
+ * @size_t ssz@ = size of output space for @s@
+ *
+ * Returns: ---
+ *
+ * Use: Signs a message, storing the results in a big-endian binary
+ * form.
+ */
+
+extern void dsa_sign(dsa_param */*dp*/, mp */*a*/,
+ const void */*m*/, size_t /*msz*/,
+ const void */*k*/, size_t /*ksz*/,
+ void */*r*/, size_t /*rsz*/,
+ void */*s*/, size_t /*ssz*/);
+
+/* --- @dsa_vrfy@ --- *
+ *
+ * Arguments: @const dsa_param *dp@ = pointer to DSA parameters
+ * @const mp *y@ = public verification key
+ * @const mp *m@ = message which was signed
+ * @const mp *r, *s@ = the signature
+ *
+ * Returns: Zero if the signature is a forgery, nonzero if it's valid.
+ *
+ * Use: Verifies a DSA digital signature.
+ */
+
+extern int dsa_vrfy(const dsa_param */*dp*/, const mp */*y*/,
+ const mp */*m*/, const mp */*r*/, const mp */*s*/);
+
+/* --- @dsa_verify@ --- *
+ *
+ * Arguments: @const dsa_param *dp@ = pointer to DSA parameters
+ * @const mp *y@ = public verification key
+ * @const void *m@ = pointer to message block
+ * @size_t msz@ = size of message block
+ * @const void *r@ = pointer to @r@ signature half
+ * @size_t rsz@ = size of @r@
+ * @const void *s@ = pointer to @s@ signature half
+ * @size_t ssz@ = size of @s@
+ *
+ * Returns: Zero if the signature is a forgery, nonzero if it's valid.
+ *
+ * Use: Verifies a DSA digital signature.
+ */
+
+extern int dsa_verify(const dsa_param */*dp*/, const mp */*y*/,
+ const void */*m*/, size_t /*msz*/,
+ const void */*r*/, size_t /*rsz*/,
+ const void */*s*/, size_t /*ssz*/);
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+ }
+#endif
+
+#endif
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