Add rivest cipher 4 (rc4) implementation

Add an implementation of RC4. This will be used by Rockchip booting but may be useful in other situations. Signed-off-by: Simon Glass <sjg@chromium.org>

Add rivest cipher 4 (rc4) implementation
Add an implementation of RC4. This will be used by Rockchip booting but may be useful in other situations. Signed-off-by: Simon Glass <sjg@chromium.org>
Simon Glass
1 parent 6e780c7a7b
Showing 3 changed files with 71 additions and 0 deletions Side-by-side Diff
include/rc4.h
lib/Makefile
lib/rc4.c
+/*
+ * (C) Copyright 2015 Google, Inc
+ *
+ * (C) Copyright 2008-2014 Rockchip Electronics
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __RC4_H
+#define __RC4_H
+
+/**
+ * rc4_encode() - encode a buf with the RC4 cipher
+ *
+ * @buf:	Buffer to encode (it is overwrite in the process
+ * @len:	Length of buffer in bytes
+ * @key:	16-byte key to use
+ */
+void rc4_encode(unsigned char *buf, unsigned int len, unsigned char key[16]);
+
+#endif
@@ -37,6 +37,7 @@
 obj-y += net_utils.o
 obj-$(CONFIG_PHYSMEM) += physmem.o
 obj-y += qsort.o
+obj-y += rc4.o
 obj-$(CONFIG_SHA1) += sha1.o
 obj-$(CONFIG_SUPPORT_EMMC_RPMB) += sha256.o
 obj-$(CONFIG_SHA256) += sha256.o
+/*
+ * (C) Copyright 2015 Google, Inc
+ *
+ * (C) Copyright 2008-2014 Rockchip Electronics
+ *
+ * Rivest Cipher 4 (RC4) implementation
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef USE_HOSTCC
+#include <common.h>
+#endif
+#include <rc4.h>
+
+void rc4_encode(unsigned char *buf, unsigned int len, unsigned char key[16])
+{
+	unsigned char s[256], k[256], temp;
+	unsigned short i, j, t;
+	int ptr;
+
+	j = 0;
+	for (i = 0; i < 256; i++) {
+		s[i] = (unsigned char)i;
+		j &= 0x0f;
+		k[i] = key[j];
+		j++;
+	}
+
+	j = 0;
+	for (i = 0; i < 256; i++) {
+		j = (j + s[i] + k[i]) % 256;
+		temp = s[i];
+		s[i] = s[j];
+		s[j] = temp;
+	}
+
+	i = 0;
+	j = 0;
+	for (ptr = 0; ptr < len; ptr++) {
+		i = (i + 1) % 256;
+		j = (j + s[i]) % 256;
+		temp = s[i];
+		s[i] = s[j];
+		s[j] = temp;
+		t = (s[i] + (s[j] % 256)) % 256;
+		buf[ptr] = buf[ptr] ^ s[t];
+	}
+}
	1	+/*
	2	+ * (C) Copyright 2015 Google, Inc
	3	+ *
	4	+ * (C) Copyright 2008-2014 Rockchip Electronics
	5	+ *
	6	+ * SPDX-License-Identifier: GPL-2.0+
	7	+ */
	8	+
	9	+#ifndef __RC4_H
	10	+#define __RC4_H
	11	+
	12	+/**
	13	+ * rc4_encode() - encode a buf with the RC4 cipher
	14	+ *
	15	+ * @buf: Buffer to encode (it is overwrite in the process
	16	+ * @len: Length of buffer in bytes
	17	+ * @key: 16-byte key to use
	18	+ */
	19	+void rc4_encode(unsigned char *buf, unsigned int len, unsigned char key[16]);
	20	+
	21	+#endif
...	...	@@ -37,6 +37,7 @@
37	37	obj-y += net_utils.o
38	38	obj-$(CONFIG_PHYSMEM) += physmem.o
39	39	obj-y += qsort.o
	40	+obj-y += rc4.o
40	41	obj-$(CONFIG_SHA1) += sha1.o
41	42	obj-$(CONFIG_SUPPORT_EMMC_RPMB) += sha256.o
42	43	obj-$(CONFIG_SHA256) += sha256.o
	1	+/*
	2	+ * (C) Copyright 2015 Google, Inc
	3	+ *
	4	+ * (C) Copyright 2008-2014 Rockchip Electronics
	5	+ *
	6	+ * Rivest Cipher 4 (RC4) implementation
	7	+ *
	8	+ * SPDX-License-Identifier: GPL-2.0+
	9	+ */
	10	+
	11	+#ifndef USE_HOSTCC
	12	+#include <common.h>
	13	+#endif
	14	+#include <rc4.h>
	15	+
	16	+void rc4_encode(unsigned char *buf, unsigned int len, unsigned char key[16])
	17	+{
	18	+ unsigned char s[256], k[256], temp;
	19	+ unsigned short i, j, t;
	20	+ int ptr;
	21	+
	22	+ j = 0;
	23	+ for (i = 0; i < 256; i++) {
	24	+ s[i] = (unsigned char)i;
	25	+ j &= 0x0f;
	26	+ k[i] = key[j];
	27	+ j++;
	28	+ }
	29	+
	30	+ j = 0;
	31	+ for (i = 0; i < 256; i++) {
	32	+ j = (j + s[i] + k[i]) % 256;
	33	+ temp = s[i];
	34	+ s[i] = s[j];
	35	+ s[j] = temp;
	36	+ }
	37	+
	38	+ i = 0;
	39	+ j = 0;
	40	+ for (ptr = 0; ptr < len; ptr++) {
	41	+ i = (i + 1) % 256;
	42	+ j = (j + s[i]) % 256;
	43	+ temp = s[i];
	44	+ s[i] = s[j];
	45	+ s[j] = temp;
	46	+ t = (s[i] + (s[j] % 256)) % 256;
	47	+ buf[ptr] = buf[ptr] ^ s[t];
	48	+ }
	49	+}