--- /dev/null
+/* -*-c-*-
+ *
+ * Chinese Remainder Theorem computations (Gauss's 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.
+ */
+
+#ifndef CATACOMB_MPCRT_H
+#define CATACOMB_MPCRT_H
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <stddef.h>
+
+#ifndef CATACOMB_MP_H
+# include "mp.h"
+#endif
+
+#ifndef CATACOMB_MPBARRETT_H
+# include "mpbarrett.h"
+#endif
+
+/*----- Data structures ---------------------------------------------------*/
+
+typedef struct mpcrt_mod {
+ mp *m; /* %$n_i$% -- the modulus */
+ mp *n; /* %$N_i = n / n_i$% */
+ mp *ni; /* %$M_i = N_i^{-1} \bmod n_i$% */
+ mp *nni; /* %$N_i M_i \bmod m$% */
+} mpcrt_mod;
+
+typedef struct mpcrt {
+ size_t k; /* Number of distinct moduli */
+ mpbarrett mb; /* Barrett context for product */
+ mpcrt_mod *v; /* Vector of information for each */
+} mpcrt;
+
+/*----- Functions provided ------------------------------------------------*/
+
+/* --- @mpcrt_create@ --- *
+ *
+ * Arguments: @mpcrt *c@ = pointer to CRT context
+ * @mpcrt_mod *v@ = pointer to vector of moduli
+ * @size_t k@ = number of moduli
+ * @mp *n@ = product of all moduli (@MP_NEW@ if unknown)
+ *
+ * Returns: ---
+ *
+ * Use: Initializes a context for solving Chinese Remainder Theorem
+ * problems. The vector of moduli can be incomplete. Omitted
+ * items must be left as null pointers. Not all combinations of
+ * missing things can be coped with, even if there is
+ * technically enough information to cope. For example, if @n@
+ * is unspecified, all the @m@ values must be present, even if
+ * there is one modulus with both @m@ and @n@ (from which the
+ * product of all moduli could clearly be calculated).
+ */
+
+extern void mpcrt_create(mpcrt */*c*/, mpcrt_mod */*v*/,
+ size_t /*k*/, mp */*n*/);
+
+/* --- @mpcrt_destroy@ --- *
+ *
+ * Arguments: @mpcrt *c@ - pointer to CRT context
+ *
+ * Returns: ---
+ *
+ * Use: Destroys a CRT context, releasing all the resources it holds.
+ */
+
+extern void mpcrt_destroy(mpcrt */*c*/);
+
+/* --- @mpcrt_solve@ --- *
+ *
+ * Arguments: @mpcrt *c@ = pointer to CRT context
+ * @mp *d@ = fake destination
+ * @mp **v@ = array of residues
+ *
+ * Returns: The unique solution modulo the product of the individual
+ * moduli, which leaves the given residues.
+ *
+ * Use: Constructs a result given its residue modulo an array of
+ * coprime integers. This can be used to improve performance of
+ * RSA encryption or Blum-Blum-Shub generation if the factors
+ * of the modulus are known, since results can be computed mod
+ * each of the individual factors and then combined at the end.
+ * This is rather faster than doing the full-scale modular
+ * exponentiation.
+ */
+
+extern mp *mpcrt_solve(mpcrt */*c*/, mp */*d*/, mp **/*v*/);
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+ }
+#endif
+
+#endif