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authorWerner Koch <wk@gnupg.org>2000-10-10 14:54:06 +0200
committerWerner Koch <wk@gnupg.org>2000-10-10 14:54:06 +0200
commitb75f734a11a121c85c7a1f914df129fe9289fe41 (patch)
tree363aa5b6a0706e8c9079b0e4ade75a5338aafbcc /cipher
parentSee ChangeLog: Fri Oct 6 14:29:16 CEST 2000 Werner Koch (diff)
downloadgnupg2-b75f734a11a121c85c7a1f914df129fe9289fe41.tar.xz
gnupg2-b75f734a11a121c85c7a1f914df129fe9289fe41.zip
Added the arcfour cipher which is of use for GNUTLS.
According to the selftest, it does not yet work :-((.
Diffstat (limited to 'cipher')
-rw-r--r--cipher/arcfour.c165
-rw-r--r--cipher/arcfour.h41
2 files changed, 206 insertions, 0 deletions
diff --git a/cipher/arcfour.c b/cipher/arcfour.c
new file mode 100644
index 000000000..61d0d2988
--- /dev/null
+++ b/cipher/arcfour.c
@@ -0,0 +1,165 @@
+/* arcfour.c - The arcfour stream cipher
+ * Copyright (C) 2000 Free Software Foundation, Inc.
+ *
+ * For a description of the algorithm, see:
+ * Bruce Schneier: Applied Cryptography. John Wiley & Sons, 1996.
+ * ISBN 0-471-11709-9. Pages 397 ff.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "types.h"
+#include "g10lib.h"
+#include "arcfour.h"
+
+static const char *selftest(void);
+
+
+typedef struct {
+ int idx_i, idx_j;
+ byte sbox[256];
+} ARCFOUR_context;
+
+
+static void
+encrypt_stream( ARCFOUR_context *ctx,
+ byte *outbuf, const byte *inbuf, unsigned int length )
+{
+ int t;
+ int i = ctx->idx_i;
+ int j = ctx->idx_j;
+ byte *sbox = ctx->sbox;
+
+ while ( length-- ) {
+ i = (i+1) % 256;
+ j = (j + sbox[i]) % 256;
+ t = sbox[i]; sbox[i] = sbox[j]; sbox[j] = t;
+ *outbuf++ = *inbuf++ ^ sbox[(sbox[i] + sbox[j]) % 256];
+ }
+
+ ctx->idx_i = i;
+ ctx->idx_j = j;
+}
+
+
+static int
+arcfour_setkey( ARCFOUR_context *ctx, const byte *key, unsigned int keylen )
+{
+ static int initialized;
+ static const char* selftest_failed;
+ int i, j;
+ byte karr[256];
+
+ if( !initialized ) {
+ initialized = 1;
+ selftest_failed = selftest();
+ if( selftest_failed )
+ fprintf(stderr,"ARCFOUR selftest failed (%s)\n", selftest_failed );
+ }
+ if( selftest_failed )
+ return GCRYERR_SELFTEST;
+
+ if( keylen < 40 )
+ return GCRYERR_INV_KEYLEN;
+
+ ctx->idx_i = ctx->idx_j = 0;
+ for (i=0; i < 256; i++ )
+ ctx->sbox[i] = i;
+ for (i=0; i < 256; i++ )
+ karr[i] = key[i%keylen];
+ for (i=j=0; i < 256; i++ ) {
+ int t;
+ j = (j + ctx->sbox[i] + karr[i]) % 256;
+ t = ctx->sbox[i];
+ ctx->sbox[i] = ctx->sbox[j];
+ ctx->sbox[j] = t;
+ }
+ memset( karr, 0, 256 );
+
+ return 0;
+}
+
+
+static const char*
+selftest(void)
+{
+ ARCFOUR_context ctx;
+ byte scratch[16];
+
+ /* Test vector from Cryptlib labeled there:
+ * "from the State/Commerce Department" */
+ static const byte key_1[] =
+ { 0x61, 0x8A, 0x63, 0xD2, 0xFB };
+ static const byte plaintext_1[] =
+ { 0xDC, 0xEE, 0x4C, 0xF9, 0x2C };
+ static const byte ciphertext_1[] =
+ { 0xF1, 0x38, 0x29, 0xC9, 0xDE };
+
+ arcfour_setkey( &ctx, key_1, sizeof(key_1));
+ encrypt_stream( &ctx, scratch, plaintext_1, sizeof(plaintext_1));
+ if (memcmp (scratch, ciphertext_1, sizeof (ciphertext_1)))
+ return "Arcfour encryption test 1 failed.";
+ encrypt_stream(&ctx, scratch, scratch, sizeof(plaintext_1)); /* decrypt */
+ if ( memcmp (scratch, plaintext_1, sizeof (plaintext_1)))
+ return "Arcfour decryption test 1 failed.";
+ return NULL;
+}
+
+
+/****************
+ * Return some information about the algorithm. We need algo here to
+ * distinguish different flavors of the algorithm.
+ * Returns: A pointer to string describing the algorithm or NULL if
+ * the ALGO is invalid.
+ * NOTE: This is a special get_info function which is different from all
+ * others because arcfour is a stream cipher. We use this hack until
+ * we have redesign the interface.
+ */
+const char *
+arcfour_get_info( int algo, size_t *keylen, size_t *blocksize,
+ size_t *contextsize,
+ int (**r_setkey)( void *c, byte *key, unsigned keylen ),
+ void (**r_stencrypt)( void *c, byte *outbuf,
+ byte *inbuf, unsigned int nbytes ),
+ void (**r_stdecrypt)( void *c, byte *outbuf,
+ byte *inbuf, unsigned int nbytes )
+ )
+{
+ *keylen = 128; /* arbitrary value */
+ *blocksize = 1;
+ *contextsize = sizeof(ARCFOUR_context);
+ *(int (**)(ARCFOUR_context*, byte*, unsigned))r_setkey
+ = arcfour_setkey;
+ *(void (**)(ARCFOUR_context*, byte*, const byte*, unsigned))r_stencrypt
+ = encrypt_stream;
+ *(void (**)(ARCFOUR_context*, byte*, const byte*, unsigned))r_stdecrypt
+ = encrypt_stream;
+
+
+ if( algo == 301 )
+ return "ARCFOUR";
+ return NULL;
+}
+
+
+
+
diff --git a/cipher/arcfour.h b/cipher/arcfour.h
new file mode 100644
index 000000000..a4f1cb59b
--- /dev/null
+++ b/cipher/arcfour.h
@@ -0,0 +1,41 @@
+/* arcfour.h
+ * Copyright (C) 2000 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+#ifndef G10_ARCFOUR_H
+#define G10_ARCFOUR_H
+
+#include "types.h"
+
+/* NOTE: This is a special get_info function which is different from all
+ * others because arcfour is a stream cipher. We use this hack until
+ * we have redesigned the interface.
+ */
+const char *
+arcfour_get_info( int algo, size_t *keylen, size_t *blocksize,
+ size_t *contextsize,
+ int (**r_setkey)( void *c, byte *key, unsigned keylen ),
+ void (**r_stencrypt)( void *c, byte *outbuf,
+ byte *inbuf, unsigned int nbytes ),
+ void (**r_stdecrypt)( void *c, byte *outbuf,
+ byte *inbuf, unsigned int nbytes )
+ );
+
+
+#endif /*G10_ARCFOUR_H*/
+