From 37da2899f40661e3e9631e497da8dc59b971cbd0 Mon Sep 17 00:00:00 2001
From: "Charles.Forsyth" <devnull@localhost>
Date: Fri, 22 Dec 2006 17:07:39 +0000
Subject: 20060303a

---
 libsec/port/idea.c | 168 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 168 insertions(+)
 create mode 100644 libsec/port/idea.c

(limited to 'libsec/port/idea.c')

diff --git a/libsec/port/idea.c b/libsec/port/idea.c
new file mode 100644
index 00000000..47b60ae3
--- /dev/null
+++ b/libsec/port/idea.c
@@ -0,0 +1,168 @@
+#include "os.h"
+#include "mp.h"
+#include "libsec.h"
+
+#define KEYLEN	52
+
+#define	MODA	0x10000
+#define	MODM	0x10001
+#define	MASKA	(MODA-1)
+
+#define 	OP1(x, y)		((x) ^ (y))
+#define	OP2(x, y)		(((x) + (y)) & MASKA)
+#define 	OP3(x, y)		mod(x, y)
+
+#define	OP2INV(x)	(-(x))
+#define	OP3INV(x)	inv(x)
+
+#define BIGEND(k, i)	((k[i]<<8)|k[i+1])
+#define MSB(x)		((x)>>8)
+#define LSB(x)		((x)&0xff)
+
+static ushort
+mod(ushort x, ushort y)
+{
+	ushort q, r;
+	uint z;
+
+	if (x == 0)
+		return 1-y;
+	if (y == 0)
+		return 1-x;
+	z = (uint)x*(uint)y;
+	q = z >> 16;
+	r = z & MASKA;
+	return r-q+(r<q);
+}
+
+static ushort 
+inv(ushort x)
+{
+	int q, r0, r1, r2, v0, v1, v2;
+
+	if (x <= 1)
+		return x;
+	r0 = MODM;
+	r1 = x;
+	v0 = 0;
+	v1 = 1;
+	while (r1 != 0) {
+		q = r0/r1;
+		r2 = r0-q*r1;
+		v2 = v0-q*v1;
+		r0 = r1;
+		r1 = r2;
+		v0 = v1;
+		v1 = v2;
+	}
+	if (v0 < 0)
+		v0 += MODM;
+	return v0 & MASKA;
+}
+
+static void
+idea_key_setup_decrypt(ushort ek[KEYLEN], ushort dk[KEYLEN])
+{
+	int i;
+
+	for (i = 0; i < 54; i += 6) {
+		dk[i] = OP3INV(ek[48-i]);
+		dk[i+1] = OP2INV(ek[50-i]);
+		dk[i+2] = OP2INV(ek[49-i]);
+		dk[i+3] = OP3INV(ek[51-i]);
+		if (i < 48) {
+			dk[i+4] = ek[46-i];
+			dk[i+5] = ek[47-i];
+		}
+	}
+}
+
+void
+idea_key_setup(uchar key[16], ushort ek[2*KEYLEN])
+{
+	int i, j;
+	ushort tmp, *e = ek;
+
+	for (i = 0; i < 8; i++)
+		ek[i] = BIGEND(key, 2*i);
+	for (i = 8, j = 1; i < KEYLEN; i++, j++) {
+		ek[i] = (e[j&7]<<9)|(e[(j+1)&7]>>7);
+		if (((i+1) & 7) == 0)
+			e += 8;
+	}
+	tmp = ek[49];
+	ek[49] = ek[50];
+	ek[50] = tmp;
+	idea_key_setup_decrypt(ek, &ek[KEYLEN]);
+}
+
+void
+idea_cipher(ushort key[2*KEYLEN], uchar text[8], int decrypting)
+{
+	int i;
+	ushort *k;
+	ushort x[4];
+	ushort tmp, yout, zout;
+
+	k = decrypting ? &key[KEYLEN] : key;
+	for (i = 0; i < 4; i++)
+		x[i] = BIGEND(text, 2*i);
+	for (i = 0; i < 17; i++) {
+		if (!(i&1)) {		/* odd round */
+			x[0] = OP3(x[0], k[3*i]);
+			tmp = OP2(x[2], k[3*i+2]);
+			x[2] = OP2(x[1], k[3*i+1]);
+			x[3] = OP3(x[3], k[3*i+3]);
+			x[1] = tmp;
+		}
+		else {
+			tmp = OP3(k[3*i+1], OP1(x[0], x[1]));
+			yout = OP3(OP2(tmp, OP1(x[2], x[3])), k[3*i+2]);
+			zout = OP2(tmp, yout);
+			x[0] = OP1(x[0], yout);
+			x[1] = OP1(x[1], yout);
+			x[2] = OP1(x[2], zout);
+			x[3] = OP1(x[3], zout);
+		}
+	}
+	for (i = 0; i < 4; i++) {
+		text[2*i] = MSB(x[i]); 
+		text[2*i+1] = LSB(x[i]);
+	}
+}
+
+void
+setupIDEAstate(IDEAstate *s, uchar key[16], uchar *ivec)
+{
+	memset(s, 0, sizeof(*s));
+	memmove(s->key, key, sizeof(s->key));
+	idea_key_setup(key, s->edkey);
+	if(ivec)
+		memmove(s->ivec, ivec, 8);
+}
+
+/*
+void
+main()
+{
+	uchar key[] = { 0x00, 0x01, 0x00, 0x02, 0x00, 0x03, 0x00, 0x04,
+			        0x00, 0x05, 0x00, 0x06, 0x00, 0x07, 0x00, 0x08 };
+	uchar plain[] = { 0x00, 0x00, 0x00, 0x01, 0x00, 0x02, 0x00, 0x03 };
+	uchar cipher[] = { 0x11, 0xFB, 0xED, 0x2B, 0x01, 0x98, 0x6D, 0xE5 };
+	ushort edkey[2*KEYLEN];
+	uchar tmp[8];
+
+	memcpy(tmp, plain, 8);
+	idea_key_setup(key, edkey);
+	idea_cipher(edkey, tmp, 0);
+	if (memcmp(tmp, cipher, 8)) {
+		print("encrypt wrong\n");
+		exits("");
+	}
+	idea_cipher(edkey, tmp, 1);
+	if (memcmp(tmp, plain, 8)) {
+		print("decrypt wrong\n");
+		exits("");
+	}
+}
+*/	
-- 
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