- Support for DES weak keys and parity bits added
diff --git a/library/des.c b/library/des.c
index f470220..39ff216 100644
--- a/library/des.c
+++ b/library/des.c
@@ -290,7 +290,95 @@
#define SWAP(a,b) { unsigned long t = a; a = b; b = t; t = 0; }
-static void des_setkey( unsigned long SK[32], const unsigned char key[8] )
+static const unsigned char odd_parity_table[128] = { 1, 2, 4, 7, 8,
+ 11, 13, 14, 16, 19, 21, 22, 25, 26, 28, 31, 32, 35, 37, 38, 41, 42, 44,
+ 47, 49, 50, 52, 55, 56, 59, 61, 62, 64, 67, 69, 70, 73, 74, 76, 79, 81,
+ 82, 84, 87, 88, 91, 93, 94, 97, 98, 100, 103, 104, 107, 109, 110, 112,
+ 115, 117, 118, 121, 122, 124, 127, 128, 131, 133, 134, 137, 138, 140,
+ 143, 145, 146, 148, 151, 152, 155, 157, 158, 161, 162, 164, 167, 168,
+ 171, 173, 174, 176, 179, 181, 182, 185, 186, 188, 191, 193, 194, 196,
+ 199, 200, 203, 205, 206, 208, 211, 213, 214, 217, 218, 220, 223, 224,
+ 227, 229, 230, 233, 234, 236, 239, 241, 242, 244, 247, 248, 251, 253,
+ 254 };
+
+void des_key_set_parity( unsigned char key[DES_KEY_SIZE] )
+{
+ int i;
+
+ for( i = 0; i < DES_KEY_SIZE; i++ )
+ key[i] = odd_parity_table[key[i] / 2];
+}
+
+/*
+ * Check the given key's parity, returns 1 on failure, 0 on SUCCESS
+ */
+int des_key_check_key_parity( const unsigned char key[DES_KEY_SIZE] )
+{
+ int i;
+
+ for( i = 0; i < DES_KEY_SIZE; i++ )
+ if ( key[i] != odd_parity_table[key[i] / 2] )
+ return( 1 );
+
+ return( 0 );
+}
+
+/*
+ * Table of weak and semi-weak keys
+ *
+ * Source: http://en.wikipedia.org/wiki/Weak_key
+ *
+ * Weak:
+ * Alternating ones + zeros (0x0101010101010101)
+ * Alternating 'F' + 'E' (0xFEFEFEFEFEFEFEFE)
+ * '0xE0E0E0E0F1F1F1F1'
+ * '0x1F1F1F1F0E0E0E0E'
+ *
+ * Semi-weak:
+ * 0x011F011F010E010E and 0x1F011F010E010E01
+ * 0x01E001E001F101F1 and 0xE001E001F101F101
+ * 0x01FE01FE01FE01FE and 0xFE01FE01FE01FE01
+ * 0x1FE01FE00EF10EF1 and 0xE01FE01FF10EF10E
+ * 0x1FFE1FFE0EFE0EFE and 0xFE1FFE1FFE0EFE0E
+ * 0xE0FEE0FEF1FEF1FE and 0xFEE0FEE0FEF1FEF1
+ *
+ */
+
+#define WEAK_KEY_COUNT 16
+
+static const unsigned char weak_key_table[WEAK_KEY_COUNT][DES_KEY_SIZE] =
+{
+ { 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 },
+
+ { 0x01, 0x1F, 0x01, 0x1F, 0x01, 0x0E, 0x01, 0x0E },
+ { 0x1F, 0x01, 0x1F, 0x01, 0x0E, 0x01, 0x0E, 0x01 },
+ { 0x01, 0xE0, 0x01, 0xE0, 0x01, 0xF1, 0x01, 0xF1 },
+ { 0xE0, 0x01, 0xE0, 0x01, 0xF1, 0x01, 0xF1, 0x01 },
+ { 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 },
+ { 0x1F, 0xFE, 0x1F, 0xFE, 0x0E, 0xFE, 0x0E, 0xFE },
+ { 0xFE, 0x1F, 0xFE, 0x1F, 0xFE, 0x0E, 0xFE, 0x0E },
+ { 0xE0, 0xFE, 0xE0, 0xFE, 0xF1, 0xFE, 0xF1, 0xFE },
+ { 0xFE, 0xE0, 0xFE, 0xE0, 0xFE, 0xF1, 0xFE, 0xF1 }
+};
+
+int des_key_check_weak( const unsigned char key[DES_KEY_SIZE] )
+{
+ int i;
+
+ for( i = 0; i < WEAK_KEY_COUNT; i++ )
+ if( memcmp( weak_key_table[i], key, DES_KEY_SIZE) == 0)
+ return( 0 );
+
+ return( 1 );
+}
+
+static void des_setkey( unsigned long SK[32], const unsigned char key[DES_KEY_SIZE] )
{
int i;
unsigned long X, Y, T;
@@ -362,7 +450,7 @@
/*
* DES key schedule (56-bit, encryption)
*/
-int des_setkey_enc( des_context *ctx, const unsigned char key[8] )
+int des_setkey_enc( des_context *ctx, const unsigned char key[DES_KEY_SIZE] )
{
des_setkey( ctx->sk, key );
@@ -372,7 +460,7 @@
/*
* DES key schedule (56-bit, decryption)
*/
-int des_setkey_dec( des_context *ctx, const unsigned char key[8] )
+int des_setkey_dec( des_context *ctx, const unsigned char key[DES_KEY_SIZE] )
{
int i;
@@ -389,7 +477,7 @@
static void des3_set2key( unsigned long esk[96],
unsigned long dsk[96],
- const unsigned char key[16] )
+ const unsigned char key[DES_KEY_SIZE*2] )
{
int i;
@@ -415,7 +503,7 @@
/*
* Triple-DES key schedule (112-bit, encryption)
*/
-int des3_set2key_enc( des3_context *ctx, const unsigned char key[16] )
+int des3_set2key_enc( des3_context *ctx, const unsigned char key[DES_KEY_SIZE * 2] )
{
unsigned long sk[96];
@@ -428,7 +516,7 @@
/*
* Triple-DES key schedule (112-bit, decryption)
*/
-int des3_set2key_dec( des3_context *ctx, const unsigned char key[16] )
+int des3_set2key_dec( des3_context *ctx, const unsigned char key[DES_KEY_SIZE * 2] )
{
unsigned long sk[96];
@@ -464,7 +552,7 @@
/*
* Triple-DES key schedule (168-bit, encryption)
*/
-int des3_set3key_enc( des3_context *ctx, const unsigned char key[24] )
+int des3_set3key_enc( des3_context *ctx, const unsigned char key[DES_KEY_SIZE * 3] )
{
unsigned long sk[96];
@@ -477,7 +565,7 @@
/*
* Triple-DES key schedule (168-bit, decryption)
*/
-int des3_set3key_dec( des3_context *ctx, const unsigned char key[24] )
+int des3_set3key_dec( des3_context *ctx, const unsigned char key[DES_KEY_SIZE * 3] )
{
unsigned long sk[96];