From ad08f5e90d1b1976229e999fee71668a18f6572e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niels=20M=C3=B6ller?= <nisse@lysator.liu.se>
Date: Sat, 7 Oct 2000 02:14:06 +0200
Subject: [PATCH] * src/symmetric/serpent.c (serpent_setup): Added key_size
argument, and added key padding (appearantly not yet working).
Rev: src/symmetric/include/serpent.h:1.3
Rev: src/symmetric/serpent.c:1.3
---
include/serpent.h | 7 ++++++-
serpent.c | 28 ++++++++++++++++++++++++++--
2 files changed, 32 insertions(+), 3 deletions(-)
diff --git a/include/serpent.h b/include/serpent.h
index 0cf482a1..94d98ed5 100644
--- a/include/serpent.h
+++ b/include/serpent.h
@@ -21,13 +21,18 @@
to using key lengths less than 256 bits. */
#define SERPENT_KEYSIZE 32
+/* Allow keys of size 128 <= bits <= 256 */
+
+#define SERPENT_MIN_KEYSIZE 16
+#define SERPENT_MAX_KEYSIZE 32
+
typedef struct {
UINT32 keys[33][4]; /* key schedule */
} SERPENT_context;
/* This performs Serpent's key scheduling algorithm. */
void
-serpent_setup(SERPENT_context *ctx, const UINT8 *key);
+serpent_setup(SERPENT_context *ctx, UINT32 key_size, const UINT8 *key);
/*
* serpent_encrypt()
diff --git a/serpent.c b/serpent.c
index 20112a92..32161aad 100644
--- a/serpent.c
+++ b/serpent.c
@@ -36,16 +36,37 @@
#include "serpent.h"
#include "serpentsboxes.h"
+#include <assert.h>
+
/* The functions */
void
-serpent_setup(SERPENT_context *ctx, const UINT8 *key)
+serpent_setup(SERPENT_context *ctx, UINT32 key_size, const UINT8 *key)
{
UINT32 i, j;
UINT32 w[132], k[132];
UINT32 kd[8];
const UINT8 *kptr;
- kptr = key;
+ assert(key_size >= SERPENT_MIN_KEYSIZE);
+ assert(key_size <= SERPENT_MAX_KEYSIZE);
+
+ if (key_size == SERPENT_KEYSIZE)
+ kptr = key;
+ else
+ {
+ /* Expand key by appending bits 1000...0. */
+ UINT8 *ekey = alloca(SERPENT_KEYSIZE);
+ unsigned i = key_size;
+
+ memcpy(ekey, key, i);
+ ekey[i++] = 0x01;
+
+ while (i < SERPENT_KEYSIZE)
+ ekey[i++] = 0;
+
+ kptr = ekey;
+ }
+
for (i=0; i<8; i++) {
kd[i] = 0;
for (j=0; j<4; j++)
@@ -55,8 +76,11 @@ serpent_setup(SERPENT_context *ctx, const UINT8 *key)
for(i=0; i<8; i++)
w[i]=kd[i];
+#if 0
for(i++; i<8; i++)
w[i]=0;
+#endif
+
for(i=8; i<16; i++)
w[i]=ROL(w[i-8]^w[i-5]^w[i-3]^w[i-1]^PHI^(i-8),11);
for(i=0; i<8; i++)
--
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