From ec7611d74a6f7a740f8720e62d92efecb42da521 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niels=20M=C3=B6ller?= <nisse@lysator.liu.se>
Date: Sun, 22 Oct 2000 22:27:59 +0200
Subject: [PATCH] * src/symmetric/arcfour.c (arcfour_crypt): Changed argument
order. (arcfour_set_key): Likewise. (arcfour_stream): New function.
(arcfour_update_key): New function. (arcfour_init): New function.
Rev: src/symmetric/arcfour.c:1.5
Rev: src/symmetric/include/arcfour.h:1.2
---
arcfour.c | 53 +++++++++++++++++++++++++++++++++++++++++++----
include/arcfour.h | 13 ++++++++++--
2 files changed, 60 insertions(+), 6 deletions(-)
diff --git a/arcfour.c b/arcfour.c
index 100f9cc0..1c0e717e 100644
--- a/arcfour.c
+++ b/arcfour.c
@@ -34,7 +34,52 @@ RCSID("$Id$");
#define SWAP(a,b) do { int _t = a; a = b; b = _t; } while(0)
-void arcfour_set_key(struct arcfour_ctx *ctx, const UINT8 *key, UINT32 len)
+void arcfour_init(struct arcfour_ctx *ctx)
+{
+ unsigned i;
+
+ /* Initialize context */
+
+ for (i = 0; i<256; i++)
+ ctx->S[i] = i;
+}
+
+void arcfour_update_key(struct arcfour_ctx *ctx,
+ UINT32 length, const UINT8 *key)
+{
+ register UINT8 i = ctx->i;
+ register UINT8 j = ctx->j;
+
+ unsigned k;
+
+ for (k = 0; k<length; k++)
+ {
+ i++; i &= 0xff;
+ j += ctx->S[i] + key[k]; j &= 0xff;
+ SWAP(ctx->S[i], ctx->S[j]);
+ }
+ ctx->i = i; ctx->j = j;
+}
+
+void arcfour_stream(struct arcfour_ctx *ctx,
+ UINT32 length, UINT8 *dest)
+{
+ register UINT8 i = ctx->i;
+ register UINT8 j = ctx->j;
+ unsigned k;
+
+ for (k = 0; k<length; k++)
+ {
+ i++; i &= 0xff;
+ j += ctx->S[i]; j &= 0xff;
+ SWAP(ctx->S[i], ctx->S[j]);
+ dest[k] = ctx->S[ (ctx->S[i] + ctx->S[j]) & 0xff ];
+ }
+
+ ctx->i = i; ctx->j = j;
+}
+
+void arcfour_set_key(struct arcfour_ctx *ctx, UINT32 length, const UINT8 *key)
{
register UINT8 j; /* Depends on the eight-bitness of these variables. */
unsigned i;
@@ -49,19 +94,19 @@ void arcfour_set_key(struct arcfour_ctx *ctx, const UINT8 *key, UINT32 len)
do {
j += ctx->S[i] + key[k];
SWAP(ctx->S[i], ctx->S[j]);
- k = (k+1) % len; /* Repeat key if needed */
+ k = (k+1) % length; /* Repeat key if needed */
} while(++i < 256);
ctx->i = ctx->j = 0;
}
void arcfour_crypt(struct arcfour_ctx *ctx, UINT8 *dest,
- const UINT8 *src, UINT32 len)
+ UINT32 length, const UINT8 *src)
{
register UINT8 i, j;
i = ctx->i; j = ctx->j;
- while(len--)
+ while(length--)
{
i++; i &= 0xff;
j += ctx->S[i]; j &= 0xff;
diff --git a/include/arcfour.h b/include/arcfour.h
index 8287cc3a..300987b3 100644
--- a/include/arcfour.h
+++ b/include/arcfour.h
@@ -16,8 +16,17 @@ struct arcfour_ctx {
void arcfour_init(struct arcfour_ctx *ctx);
#endif
-void arcfour_set_key(struct arcfour_ctx *ctx, const UINT8 *key, UINT32 len);
+/* Encryption functions */
+void arcfour_set_key(struct arcfour_ctx *ctx, UINT32 length, const UINT8 *key);
void arcfour_crypt(struct arcfour_ctx *ctx, UINT8 *dest,
- const UINT8 *src, UINT32 len);
+ UINT32 length, const UINT8 *src);
+
+/* Using arcfour as a randomness generator. */
+void arcfour_init(struct arcfour_ctx *ctx);
+void arcfour_update_key(struct arcfour_ctx *ctx,
+ UINT32 length, const UINT8 *key);
+void arcfour_stream(struct arcfour_ctx *ctx,
+ UINT32 length, UINT8 *dest);
+
#endif /* ARCFOUR_H_INCLUDED */
--
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