--- /dev/null
+/* -*-c-*-
+ *
+ * [RSA encryption with padding *
+ * (c) 2000 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.
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <mLib/alloc.h>
+#include <mLib/bits.h>
+#include <mLib/dstr.h>
+
+#include "mp.h"
+#include "mpmont.h"
+#include "rsa.h"
+
+/*----- Public key operations ---------------------------------------------*/
+
+/* --- @rsa_pubcreate@ --- *
+ *
+ * Arguments: @rsa_pubctx *rd@ = pointer to an RSA public key context
+ * @rsa_pub *rp@ = pointer to RSA public key
+ *
+ * Returns: ---
+ *
+ * Use: Initializes an RSA public-key context.
+ */
+
+void rsa_pubcreate(rsa_pubctx *rd, rsa_pub *rp)
+{
+ rd->rp = rp;
+ mpmont_create(&rd->mm, rp->n);
+}
+
+/* --- @rsa_pubdestroy@ --- *
+ *
+ * Arguments: @rsa_pubctx *rd@ = pointer to an RSA public key context
+ *
+ * Returns: ---
+ *
+ * Use: Destroys an RSA public-key context.
+ */
+
+void rsa_pubdestroy(rsa_pubctx *rd)
+{
+ mpmont_destroy(&rd->mm);
+}
+
+/* --- @rsa_pubop@ --- *
+ *
+ * Arguments: @rsa_pubctx *rd@ = pointer to an RSA public key context
+ * @mp *d@ = destination
+ * @mp *p@ = input message
+ *
+ * Returns: The transformed output message.
+ *
+ * Use: Performs an RSA public key operation.
+ */
+
+mp *rsa_pubop(rsa_pubctx *rd, mp *d, mp *p)
+{
+ return (mpmont_exp(&rd->mm, d, p, rd->rp->e));
+}
+
+/* --- @rsa_qpubop@ --- *
+ *
+ * Arguments: @rsa_pub *rp@ = pointer to RSA parameters
+ * @mp *d@ = destination
+ * @mp *p@ = input message
+ *
+ * Returns: Correctly transformed output message.
+ *
+ * Use: Performs an RSA public key operation.
+ */
+
+mp *rsa_qpubop(rsa_pub *rp, mp *d, mp *c)
+{
+ rsa_pubctx rd;
+ rsa_pubcreate(&rd, rp);
+ d = rsa_pubop(&rd, d, c);
+ rsa_pubdestroy(&rd);
+ return (d);
+}
+
+/*----- Operations with padding -------------------------------------------*/
+
+/* --- @rsa_encrypt@ --- *
+ *
+ * Arguments: @rsa_pubctx *rp@ = pointer to an RSA public key context
+ * @mp *d@ = proposed destination integer
+ * @const void *m@ = pointer to input message
+ * @size_t msz@ = size of input message
+ * @rsa_pad *e@ = encoding procedure
+ * @void *earg@ = argument pointer for encoding procedure
+ *
+ * Returns: The encrypted message, as a multiprecision integer, or null
+ * on failure.
+ *
+ * Use: Does RSA encryption.
+ */
+
+mp *rsa_encrypt(rsa_pubctx *rp, mp *d, const void *m, size_t msz,
+ rsa_pad *e, void *earg)
+{
+ octet *p;
+ unsigned long nb = mp_bits(rp->rp->n);
+ size_t n = (nb + 7)/8;
+ arena *a = d && d->a ? d->a->a : arena_global;
+
+ p = x_alloc(a, n);
+ d = e(d, m, msz, p, n, nb, earg);
+ x_free(a, p);
+ return (d ? rsa_pubop(rp, d, d) : 0);
+}
+
+/* --- @rsa_verify@ --- *
+ *
+ * Arguments: @rsa_pubctx *rp@ = pointer to an RSA public key contxt
+ * @mp *s@ = the signature, as a multiprecision integer
+ * @const void *m@ = pointer to message to verify, or null
+ * @size_t msz@ = size of input message
+ * @dstr *d@ = pointer to output string, or null
+ * @rsa_vfrunpad *e@ = decoding procedure
+ * @void *earg@ = argument pointer for decoding procedure
+ *
+ * Returns: The length of the output string if successful (0 if no output
+ * was wanted); negative on failure.
+ *
+ * Use: Does RSA signature verification. To use a signature scheme
+ * with recovery, pass in @m == 0@ and @d != 0@: the recovered
+ * message should appear in @d@. To use a signature scheme with
+ * appendix, provide @m != 0@ and @d == 0@; the result should be
+ * zero for success.
+ */
+
+int rsa_verify(rsa_pubctx *rp, mp *s, const void *m, size_t msz,
+ dstr *d, rsa_vrfunpad *e, void *earg)
+{
+ mp *p = rsa_pubop(rp, MP_NEW, s);
+ unsigned long nb = mp_bits(rp->rp->n);
+ size_t n = (nb + 7)/8;
+ dstr dd = DSTR_INIT;
+ int rc;
+
+ /* --- Decoder protocol --- *
+ *
+ * We deal with two kinds of decoders: ones with message recovery and ones
+ * with appendix. A decoder with recovery will leave a message in the
+ * buffer and exit nonzero: we'll check that against @m@ if provided and
+ * just leave it otherwise. A decoder with appendix will inspect @m@ and
+ * return zero or @-1@ itself.
+ */
+
+ if (!d) d = ⅆ
+ dstr_ensure(d, n);
+ rc = e(p, m, msz, (octet *)d->buf + d->len, n, nb, earg);
+ if (rc > 0 && m) {
+ if (rc != msz || memcmp(d->buf + d->len, m, msz) != 0)
+ rc = -1;
+ else
+ rc = 0;
+ }
+ if (rc > 0)
+ d->len += rc;
+ mp_drop(p);
+ dstr_destroy(&dd);
+ return (rc);
+}
+
+/*----- That's all, folks -------------------------------------------------*/
projects / u / mdw / catacomb / blobdiff