crypto: arc4 - improve performance by using u32 for ctx and variables (d366db60) · Commits · 戴 / test

This patch changes u8 in struct arc4_ctx and variables to u32 (as AMD seems to have problem with u8 array). Below are tcrypt results of old 1-byte block cipher versus ecb(arc4) with u8 and ecb(arc4) with u32. tcrypt results, x86-64 (speed ratios: new-u32/old, new-u8/old): u32 u8 AMD Phenom II : x3.6 x2.7 Intel Core 2 : x2.0 x1.9 tcrypt results, i386 (speed ratios: new-u32/old, new-u8/old): u32 u8 Intel Atom N260 : x1.5 x1.4 Cc: Jon Oberheide <jon@oberheide.org> Signed-off-by:

Jussi Kivilinna <jussi.kivilinna@mbnet.fi> Signed-off-by:

Herbert Xu <herbert@gondor.apana.org.au>

crypto/arc4.c

+6 −6

Original line number	Diff line number	Diff line
		@@ -22,8 +22,8 @@
		#define ARC4_BLOCK_SIZE 1

		struct arc4_ctx {
		u8 S[256];
		u8 x, y;
		u32 S[256];
		u32 x, y;
		};

		static int arc4_set_key(struct crypto_tfm tfm, const u8 in_key,
		@@ -39,7 +39,7 @@ static int arc4_set_key(struct crypto_tfm tfm, const u8 in_key,
		ctx->S[i] = i;

		for (i = 0; i < 256; i++) {
		u8 a = ctx->S[i];
		u32 a = ctx->S[i];
		j = (j + in_key[k] + a) & 0xff;
		ctx->S[i] = ctx->S[j];
		ctx->S[j] = a;
		@@ -53,9 +53,9 @@ static int arc4_set_key(struct crypto_tfm tfm, const u8 in_key,
		static void arc4_crypt(struct arc4_ctx ctx, u8 out, const u8 *in,
		unsigned int len)
		{
		u8 *const S = ctx->S;
		u8 x, y, a, b;
		u8 ty, ta, tb;
		u32 *const S = ctx->S;
		u32 x, y, a, b;
		u32 ty, ta, tb;

		if (len == 0)
		return;

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