1 files changed, 85 insertions, 0 deletions
diff --git a/src/lib/crypto/builtin/des/weak_key.c b/src/lib/crypto/builtin/des/weak_key.c
new file mode 100644
index 0000000..2eab9f5
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+++ b/src/lib/crypto/builtin/des/weak_key.c
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+/*
+ * lib/crypto/des/weak_key.c
+ *
+ * Copyright 1989,1990 by the Massachusetts Institute of Technology.
+ * All Rights Reserved.
+ *
+ * Export of this software from the United States of America may
+ *   require a specific license from the United States Government.
+ *   It is the responsibility of any person or organization contemplating
+ *   export to obtain such a license before exporting.
+ * 
+ * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
+ * distribute this software and its documentation for any purpose and
+ * without fee is hereby granted, provided that the above copyright
+ * notice appear in all copies and that both that copyright notice and
+ * this permission notice appear in supporting documentation, and that
+ * the name of M.I.T. not be used in advertising or publicity pertaining
+ * to distribution of the software without specific, written prior
+ * permission.  Furthermore if you modify this software you must label
+ * your software as modified software and not distribute it in such a
+ * fashion that it might be confused with the original M.I.T. software.
+ * M.I.T. makes no representations about the suitability of
+ * this software for any purpose.  It is provided "as is" without express
+ * or implied warranty.
+ * 
+ *
+ * Under U.S. law, this software may not be exported outside the US
+ * without license from the U.S. Commerce department.
+ *
+ * These routines form the library interface to the DES facilities.
+ *
+ * Originally written 8/85 by Steve Miller, MIT Project Athena.
+ */
+
+#include "k5-int.h"
+#include "des_int.h"
+
+/*
+ * The following are the weak DES keys:
+ */
+static const mit_des_cblock weak[16] = {
+    /* weak keys */
+    {0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01},
+    {0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe},
+    {0x1f,0x1f,0x1f,0x1f,0x0e,0x0e,0x0e,0x0e},
+    {0xe0,0xe0,0xe0,0xe0,0xf1,0xf1,0xf1,0xf1},
+
+    /* semi-weak */
+    {0x01,0xfe,0x01,0xfe,0x01,0xfe,0x01,0xfe},
+    {0xfe,0x01,0xfe,0x01,0xfe,0x01,0xfe,0x01},
+
+    {0x1f,0xe0,0x1f,0xe0,0x0e,0xf1,0x0e,0xf1},
+    {0xe0,0x1f,0xe0,0x1f,0xf1,0x0e,0xf1,0x0e},
+
+    {0x01,0xe0,0x01,0xe0,0x01,0xf1,0x01,0xf1},
+    {0xe0,0x01,0xe0,0x01,0xf1,0x01,0xf1,0x01},
+
+    {0x1f,0xfe,0x1f,0xfe,0x0e,0xfe,0x0e,0xfe},
+    {0xfe,0x1f,0xfe,0x1f,0xfe,0x0e,0xfe,0x0e},
+
+    {0x01,0x1f,0x01,0x1f,0x01,0x0e,0x01,0x0e},
+    {0x1f,0x01,0x1f,0x01,0x0e,0x01,0x0e,0x01},
+
+    {0xe0,0xfe,0xe0,0xfe,0xf1,0xfe,0xf1,0xfe},
+    {0xfe,0xe0,0xfe,0xe0,0xfe,0xf1,0xfe,0xf1}
+};
+
+/*
+ * mit_des_is_weak_key: returns true iff key is a [semi-]weak des key.
+ *
+ * Requires: key has correct odd parity.
+ */
+int
+mit_des_is_weak_key(mit_des_cblock key)
+{
+    unsigned int i;
+    const mit_des_cblock *weak_p = weak;
+
+    for (i = 0; i < (sizeof(weak)/sizeof(mit_des_cblock)); i++) {
+	if (!memcmp(weak_p++,key,sizeof(mit_des_cblock)))
+	    return 1;
+    }
+
+    return 0;
+}