---
crypto/des_generic.c | 13 ++++++++++++-
1 files changed, 12 insertions(+), 1 deletions(-)
diff --git a/crypto/des_generic.c b/crypto/des_generic.c
index a4f3165..ff95f7b 100644
--- a/crypto/des_generic.c
+++ b/crypto/des_generic.c
@@ -67,6 +67,12 @@ static const u8 pc1[256] = {
0xae, 0xea, 0xee, 0xee, 0xbe, 0xfa, 0xfe, 0xfe
};
+/*
+ * This table rotates the most significant 7 bits one place right.
+ * rs[i] = (i >> 1 & 0x7e) + (i << 6 & 0x80)
+ * Note that the odd elements of this array are actually
+ * "don't care"; the index used always has the low bit clear.
+ */
static const u8 rs[256] = {
0x00, 0x00, 0x80, 0x80, 0x02, 0x02, 0x82, 0x82,
0x04, 0x04, 0x84, 0x84, 0x06, 0x06, 0x86, 0x86,
@@ -102,6 +108,11 @@ static const u8 rs[256] = {
0x7c, 0x7c, 0xfc, 0xfc, 0x7e, 0x7e, 0xfe, 0xfe
};
+/*
+ * The pc2 table consists of 2 sections. Each section is
+ * 4 columns of 128 entries each. See the PC2() macro
+ * for details.
+ */
static const u32 pc2[1024] = {
0x00000000, 0x00000000, 0x00000000, 0x00000000,
0x00040000, 0x00000000, 0x04000000, 0x00100000,
@@ -590,7 +601,7 @@ static const u32 S8[64] = {
*/
unsigned long des_ekey(u32 pe[DES_EXPKEY_WORDS], const u8 k[DES_KEY_SIZE])
{
- /* K&R: long is at least 32 bits */
+ /* Long is the size of pointer, so good for indexing */
unsigned long a, b, c, d, w;
const u32 *pt = pc2;
--
1.6.0.6