Backport GCM support from HEAD. Minimal support at present: no assembly

language optimisation. [original by Andy]

4 files changed, 1912 insertions, 3 deletions

diff --git a/crypto/modes/Makefile b/crypto/modes/Makefile
index 6c85861b6c..007ceffdb6 100644
--- a/crypto/modes/Makefile
+++ b/crypto/modes/Makefile
@@ -17,14 +17,14 @@ TEST=
 APPS=
 
 LIB=$(TOP)/libcrypto.a
-LIBSRC= cbc128.c ctr128.c cts128.c cfb128.c ofb128.c
-LIBOBJ= cbc128.o ctr128.o cts128.o cfb128.o ofb128.o
+LIBSRC= cbc128.c ctr128.c cts128.c cfb128.c ofb128.c gcm128.c
+LIBOBJ= cbc128.o ctr128.o cts128.o cfb128.o ofb128.o gcm128.o
 
 SRC= $(LIBSRC)
 
 #EXHEADER= store.h str_compat.h
 EXHEADER= modes.h
-HEADER=	$(EXHEADER)
+HEADER=	modes_lcl.h $(EXHEADER)
 
 ALL=    $(GENERAL) $(SRC) $(HEADER)
 
diff --git a/crypto/modes/gcm128.c b/crypto/modes/gcm128.c
new file mode 100644
index 0000000000..2e42e71804
--- /dev/null
+++ b/crypto/modes/gcm128.c
@@ -0,0 +1,1753 @@
+/* ====================================================================
+ * Copyright (c) 2010 The OpenSSL Project.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer. 
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. All advertising materials mentioning features or use of this
+ *    software must display the following acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ *    endorse or promote products derived from this software without
+ *    prior written permission. For written permission, please contact
+ *    openssl-core@openssl.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ *    nor may "OpenSSL" appear in their names without prior written
+ *    permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ *    acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ * ====================================================================
+ */
+
+#define OPENSSL_FIPSAPI
+
+#include <openssl/crypto.h>
+#include "modes_lcl.h"
+#include <string.h>
+
+#ifndef MODES_DEBUG
+# ifndef NDEBUG
+#  define NDEBUG
+# endif
+#endif
+#include <assert.h>
+
+#if defined(BSWAP4) && defined(STRICT_ALIGNMENT)
+/* redefine, because alignment is ensured */
+#undef	GETU32
+#define	GETU32(p)	BSWAP4(*(const u32 *)(p))
+#undef	PUTU32
+#define	PUTU32(p,v)	*(u32 *)(p) = BSWAP4(v)
+#endif
+
+#define	PACK(s)		((size_t)(s)<<(sizeof(size_t)*8-16))
+#define REDUCE1BIT(V)	do { \
+	if (sizeof(size_t)==8) { \
+		u64 T = U64(0xe100000000000000) & (0-(V.lo&1)); \
+		V.lo  = (V.hi<<63)|(V.lo>>1); \
+		V.hi  = (V.hi>>1 )^T; \
+	} \
+	else { \
+		u32 T = 0xe1000000U & (0-(u32)(V.lo&1)); \
+		V.lo  = (V.hi<<63)|(V.lo>>1); \
+		V.hi  = (V.hi>>1 )^((u64)T<<32); \
+	} \
+} while(0)
+
+/*
+ * Even though permitted values for TABLE_BITS are 8, 4 and 1, it should
+ * never be set to 8. 8 is effectively reserved for testing purposes.
+ * TABLE_BITS>1 are lookup-table-driven implementations referred to as
+ * "Shoup's" in GCM specification. In other words OpenSSL does not cover
+ * whole spectrum of possible table driven implementations. Why? In
+ * non-"Shoup's" case memory access pattern is segmented in such manner,
+ * that it's trivial to see that cache timing information can reveal
+ * fair portion of intermediate hash value. Given that ciphertext is
+ * always available to attacker, it's possible for him to attempt to
+ * deduce secret parameter H and if successful, tamper with messages
+ * [which is nothing but trivial in CTR mode]. In "Shoup's" case it's
+ * not as trivial, but there is no reason to believe that it's resistant
+ * to cache-timing attack. And the thing about "8-bit" implementation is
+ * that it consumes 16 (sixteen) times more memory, 4KB per individual
+ * key + 1KB shared. Well, on pros side it should be twice as fast as
+ * "4-bit" version. And for gcc-generated x86[_64] code, "8-bit" version
+ * was observed to run ~75% faster, closer to 100% for commercial
+ * compilers... Yet "4-bit" procedure is preferred, because it's
+ * believed to provide better security-performance balance and adequate
+ * all-round performance. "All-round" refers to things like:
+ *
+ * - shorter setup time effectively improves overall timing for
+ *   handling short messages;
+ * - larger table allocation can become unbearable because of VM
+ *   subsystem penalties (for example on Windows large enough free
+ *   results in VM working set trimming, meaning that consequent
+ *   malloc would immediately incur working set expansion);
+ * - larger table has larger cache footprint, which can affect
+ *   performance of other code paths (not necessarily even from same
+ *   thread in Hyper-Threading world);
+ *
+ * Value of 1 is not appropriate for performance reasons.
+ */
+#if	TABLE_BITS==8
+
+static void gcm_init_8bit(u128 Htable[256], u64 H[2])
+{
+	int  i, j;
+	u128 V;
+
+	Htable[0].hi = 0;
+	Htable[0].lo = 0;
+	V.hi = H[0];
+	V.lo = H[1];
+
+	for (Htable[128]=V, i=64; i>0; i>>=1) {
+		REDUCE1BIT(V);
+		Htable[i] = V;
+	}
+
+	for (i=2; i<256; i<<=1) {
+		u128 *Hi = Htable+i, H0 = *Hi;
+		for (j=1; j<i; ++j) {
+			Hi[j].hi = H0.hi^Htable[j].hi;
+			Hi[j].lo = H0.lo^Htable[j].lo;
+		}
+	}
+}
+
+static void gcm_gmult_8bit(u64 Xi[2], const u128 Htable[256])
+{
+	u128 Z = { 0, 0};
+	const u8 *xi = (const u8 *)Xi+15;
+	size_t rem, n = *xi;
+	const union { long one; char little; } is_endian = {1};
+	static const size_t rem_8bit[256] = {
+		PACK(0x0000), PACK(0x01C2), PACK(0x0384), PACK(0x0246),
+		PACK(0x0708), PACK(0x06CA), PACK(0x048C), PACK(0x054E),
+		PACK(0x0E10), PACK(0x0FD2), PACK(0x0D94), PACK(0x0C56),
+		PACK(0x0918), PACK(0x08DA), PACK(0x0A9C), PACK(0x0B5E),
+		PACK(0x1C20), PACK(0x1DE2), PACK(0x1FA4), PACK(0x1E66),
+		PACK(0x1B28), PACK(0x1AEA), PACK(0x18AC), PACK(0x196E),
+		PACK(0x1230), PACK(0x13F2), PACK(0x11B4), PACK(0x1076),
+		PACK(0x1538), PACK(0x14FA), PACK(0x16BC), PACK(0x177E),
+		PACK(0x3840), PACK(0x3982), PACK(0x3BC4), PACK(0x3A06),
+		PACK(0x3F48), PACK(0x3E8A), PACK(0x3CCC), PACK(0x3D0E),
+		PACK(0x3650), PACK(0x3792), PACK(0x35D4), PACK(0x3416),
+		PACK(0x3158), PACK(0x309A), PACK(0x32DC), PACK(0x331E),
+		PACK(0x2460), PACK(0x25A2), PACK(0x27E4), PACK(0x2626),
+		PACK(0x2368), PACK(0x22AA), PACK(0x20EC), PACK(0x212E),
+		PACK(0x2A70), PACK(0x2BB2), PACK(0x29F4), PACK(0x2836),
+		PACK(0x2D78), PACK(0x2CBA), PACK(0x2EFC), PACK(0x2F3E),
+		PACK(0x7080), PACK(0x7142), PACK(0x7304), PACK(0x72C6),
+		PACK(0x7788), PACK(0x764A), PACK(0x740C), PACK(0x75CE),
+		PACK(0x7E90), PACK(0x7F52), PACK(0x7D14), PACK(0x7CD6),
+		PACK(0x7998), PACK(0x785A), PACK(0x7A1C), PACK(0x7BDE),
+		PACK(0x6CA0), PACK(0x6D62), PACK(0x6F24), PACK(0x6EE6),
+		PACK(0x6BA8), PACK(0x6A6A), PACK(0x682C), PACK(0x69EE),
+		PACK(0x62B0), PACK(0x6372), PACK(0x6134), PACK(0x60F6),
+		PACK(0x65B8), PACK(0x647A), PACK(0x663C), PACK(0x67FE),
+		PACK(0x48C0), PACK(0x4902), PACK(0x4B44), PACK(0x4A86),
+		PACK(0x4FC8), PACK(0x4E0A), PACK(0x4C4C), PACK(0x4D8E),
+		PACK(0x46D0), PACK(0x4712), PACK(0x4554), PACK(0x4496),
+		PACK(0x41D8), PACK(0x401A), PACK(0x425C), PACK(0x439E),
+		PACK(0x54E0), PACK(0x5522), PACK(0x5764), PACK(0x56A6),
+		PACK(0x53E8), PACK(0x522A), PACK(0x506C), PACK(0x51AE),
+		PACK(0x5AF0), PACK(0x5B32), PACK(0x5974), PACK(0x58B6),
+		PACK(0x5DF8), PACK(0x5C3A), PACK(0x5E7C), PACK(0x5FBE),
+		PACK(0xE100), PACK(0xE0C2), PACK(0xE284), PACK(0xE346),
+		PACK(0xE608), PACK(0xE7CA), PACK(0xE58C), PACK(0xE44E),
+		PACK(0xEF10), PACK(0xEED2), PACK(0xEC94), PACK(0xED56),
+		PACK(0xE818), PACK(0xE9DA), PACK(0xEB9C), PACK(0xEA5E),
+		PACK(0xFD20), PACK(0xFCE2), PACK(0xFEA4), PACK(0xFF66),
+		PACK(0xFA28), PACK(0xFBEA), PACK(0xF9AC), PACK(0xF86E),
+		PACK(0xF330), PACK(0xF2F2), PACK(0xF0B4), PACK(0xF176),
+		PACK(0xF438), PACK(0xF5FA), PACK(0xF7BC), PACK(0xF67E),
+		PACK(0xD940), PACK(0xD882), PACK(0xDAC4), PACK(0xDB06),
+		PACK(0xDE48), PACK(0xDF8A), PACK(0xDDCC), PACK(0xDC0E),
+		PACK(0xD750), PACK(0xD692), PACK(0xD4D4), PACK(0xD516),
+		PACK(0xD058), PACK(0xD19A), PACK(0xD3DC), PACK(0xD21E),
+		PACK(0xC560), PACK(0xC4A2), PACK(0xC6E4), PACK(0xC726),
+		PACK(0xC268), PACK(0xC3AA), PACK(0xC1EC), PACK(0xC02E),
+		PACK(0xCB70), PACK(0xCAB2), PACK(0xC8F4), PACK(0xC936),
+		PACK(0xCC78), PACK(0xCDBA), PACK(0xCFFC), PACK(0xCE3E),
+		PACK(0x9180), PACK(0x9042), PACK(0x9204), PACK(0x93C6),
+		PACK(0x9688), PACK(0x974A), PACK(0x950C), PACK(0x94CE),
+		PACK(0x9F90), PACK(0x9E52), PACK(0x9C14), PACK(0x9DD6),
+		PACK(0x9898), PACK(0x995A), PACK(0x9B1C), PACK(0x9ADE),
+		PACK(0x8DA0), PACK(0x8C62), PACK(0x8E24), PACK(0x8FE6),
+		PACK(0x8AA8), PACK(0x8B6A), PACK(0x892C), PACK(0x88EE),
+		PACK(0x83B0), PACK(0x8272), PACK(0x8034), PACK(0x81F6),
+		PACK(0x84B8), PACK(0x857A), PACK(0x873C), PACK(0x86FE),
+		PACK(0xA9C0), PACK(0xA802), PACK(0xAA44), PACK(0xAB86),
+		PACK(0xAEC8), PACK(0xAF0A), PACK(0xAD4C), PACK(0xAC8E),
+		PACK(0xA7D0), PACK(0xA612), PACK(0xA454), PACK(0xA596),
+		PACK(0xA0D8), PACK(0xA11A), PACK(0xA35C), PACK(0xA29E),
+		PACK(0xB5E0), PACK(0xB422), PACK(0xB664), PACK(0xB7A6),
+		PACK(0xB2E8), PACK(0xB32A), PACK(0xB16C), PACK(0xB0AE),
+		PACK(0xBBF0), PACK(0xBA32), PACK(0xB874), PACK(0xB9B6),
+		PACK(0xBCF8), PACK(0xBD3A), PACK(0xBF7C), PACK(0xBEBE) };
+
+	while (1) {
+		Z.hi ^= Htable[n].hi;
+		Z.lo ^= Htable[n].lo;
+
+		if ((u8 *)Xi==xi)	break;
+
+		n = *(--xi);
+
+		rem  = (size_t)Z.lo&0xff;
+		Z.lo = (Z.hi<<56)|(Z.lo>>8);
+		Z.hi = (Z.hi>>8);
+		if (sizeof(size_t)==8)
+			Z.hi ^= rem_8bit[rem];
+		else
+			Z.hi ^= (u64)rem_8bit[rem]<<32;
+	}
+
+	if (is_endian.little) {
+#ifdef BSWAP8
+		Xi[0] = BSWAP8(Z.hi);
+		Xi[1] = BSWAP8(Z.lo);
+#else
+		u8 *p = (u8 *)Xi;
+		u32 v;
+		v = (u32)(Z.hi>>32);	PUTU32(p,v);
+		v = (u32)(Z.hi);	PUTU32(p+4,v);
+		v = (u32)(Z.lo>>32);	PUTU32(p+8,v);
+		v = (u32)(Z.lo);	PUTU32(p+12,v);
+#endif
+	}
+	else {
+		Xi[0] = Z.hi;
+		Xi[1] = Z.lo;
+	}
+}
+#define GCM_MUL(ctx,Xi)   gcm_gmult_8bit(ctx->Xi.u,ctx->Htable)
+
+#elif	TABLE_BITS==4
+
+static void gcm_init_4bit(u128 Htable[16], u64 H[2])
+{
+	u128 V;
+#if defined(OPENSSL_SMALL_FOOTPRINT)
+	int  i;
+#endif
+
+	Htable[0].hi = 0;
+	Htable[0].lo = 0;
+	V.hi = H[0];
+	V.lo = H[1];
+
+#if defined(OPENSSL_SMALL_FOOTPRINT)
+	for (Htable[8]=V, i=4; i>0; i>>=1) {
+		REDUCE1BIT(V);
+		Htable[i] = V;
+	}
+
+	for (i=2; i<16; i<<=1) {
+		u128 *Hi = Htable+i;
+		int   j;
+		for (V=*Hi, j=1; j<i; ++j) {
+			Hi[j].hi = V.hi^Htable[j].hi;
+			Hi[j].lo = V.lo^Htable[j].lo;
+		}
+	}
+#else
+	Htable[8] = V;
+	REDUCE1BIT(V);
+	Htable[4] = V;
+	REDUCE1BIT(V);
+	Htable[2] = V;
+	REDUCE1BIT(V);
+	Htable[1] = V;
+	Htable[3].hi  = V.hi^Htable[2].hi, Htable[3].lo  = V.lo^Htable[2].lo;
+	V=Htable[4];
+	Htable[5].hi  = V.hi^Htable[1].hi, Htable[5].lo  = V.lo^Htable[1].lo;
+	Htable[6].hi  = V.hi^Htable[2].hi, Htable[6].lo  = V.lo^Htable[2].lo;
+	Htable[7].hi  = V.hi^Htable[3].hi, Htable[7].lo  = V.lo^Htable[3].lo;
+	V=Htable[8];
+	Htable[9].hi  = V.hi^Htable[1].hi, Htable[9].lo  = V.lo^Htable[1].lo;
+	Htable[10].hi = V.hi^Htable[2].hi, Htable[10].lo = V.lo^Htable[2].lo;
+	Htable[11].hi = V.hi^Htable[3].hi, Htable[11].lo = V.lo^Htable[3].lo;
+	Htable[12].hi = V.hi^Htable[4].hi, Htable[12].lo = V.lo^Htable[4].lo;
+	Htable[13].hi = V.hi^Htable[5].hi, Htable[13].lo = V.lo^Htable[5].lo;
+	Htable[14].hi = V.hi^Htable[6].hi, Htable[14].lo = V.lo^Htable[6].lo;
+	Htable[15].hi = V.hi^Htable[7].hi, Htable[15].lo = V.lo^Htable[7].lo;
+#endif
+#if defined(GHASH_ASM) && (defined(__arm__) || defined(__arm))
+	/*
+	 * ARM assembler expects specific dword order in Htable.
+	 */
+	{
+	int j;
+	const union { long one; char little; } is_endian = {1};
+
+	if (is_endian.little)
+		for (j=0;j<16;++j) {
+			V = Htable[j];
+			Htable[j].hi = V.lo;
+			Htable[j].lo = V.hi;
+		}
+	else
+		for (j=0;j<16;++j) {
+			V = Htable[j];
+			Htable[j].hi = V.lo<<32|V.lo>>32;
+			Htable[j].lo = V.hi<<32|V.hi>>32;
+		}
+	}
+#endif
+}
+
+#ifndef GHASH_ASM
+static const size_t rem_4bit[16] = {
+	PACK(0x0000), PACK(0x1C20), PACK(0x3840), PACK(0x2460),
+	PACK(0x7080), PACK(0x6CA0), PACK(0x48C0), PACK(0x54E0),
+	PACK(0xE100), PACK(0xFD20), PACK(0xD940), PACK(0xC560),
+	PACK(0x9180), PACK(0x8DA0), PACK(0xA9C0), PACK(0xB5E0) };
+
+static void gcm_gmult_4bit(u64 Xi[2], const u128 Htable[16])
+{
+	u128 Z;
+	int cnt = 15;
+	size_t rem, nlo, nhi;
+	const union { long one; char little; } is_endian = {1};
+
+	nlo  = ((const u8 *)Xi)[15];
+	nhi  = nlo>>4;
+	nlo &= 0xf;
+
+	Z.hi = Htable[nlo].hi;
+	Z.lo = Htable[nlo].lo;
+
+	while (1) {
+		rem  = (size_t)Z.lo&0xf;
+		Z.lo = (Z.hi<<60)|(Z.lo>>4);
+		Z.hi = (Z.hi>>4);
+		if (sizeof(size_t)==8)
+			Z.hi ^= rem_4bit[rem];
+		else
+			Z.hi ^= (u64)rem_4bit[rem]<<32;
+
+		Z.hi ^= Htable[nhi].hi;
+		Z.lo ^= Htable[nhi].lo;
+
+		if (--cnt<0)		break;
+
+		nlo  = ((const u8 *)Xi)[cnt];
+		nhi  = nlo>>4;
+		nlo &= 0xf;
+
+		rem  = (size_t)Z.lo&0xf;
+		Z.lo = (Z.hi<<60)|(Z.lo>>4);
+		Z.hi = (Z.hi>>4);
+		if (sizeof(size_t)==8)
+			Z.hi ^= rem_4bit[rem];
+		else
+			Z.hi ^= (u64)rem_4bit[rem]<<32;
+
+		Z.hi ^= Htable[nlo].hi;
+		Z.lo ^= Htable[nlo].lo;
+	}
+
+	if (is_endian.little) {
+#ifdef BSWAP8
+		Xi[0] = BSWAP8(Z.hi);
+		Xi[1] = BSWAP8(Z.lo);
+#else
+		u8 *p = (u8 *)Xi;
+		u32 v;
+		v = (u32)(Z.hi>>32);	PUTU32(p,v);
+		v = (u32)(Z.hi);	PUTU32(p+4,v);
+		v = (u32)(Z.lo>>32);	PUTU32(p+8,v);
+		v = (u32)(Z.lo);	PUTU32(p+12,v);
+#endif
+	}
+	else {
+		Xi[0] = Z.hi;
+		Xi[1] = Z.lo;
+	}
+}
+
+#if !defined(OPENSSL_SMALL_FOOTPRINT)
+/*
+ * Streamed gcm_mult_4bit, see CRYPTO_gcm128_[en|de]crypt for
+ * details... Compiler-generated code doesn't seem to give any
+ * performance improvement, at least not on x86[_64]. It's here
+ * mostly as reference and a placeholder for possible future
+ * non-trivial optimization[s]...
+ */
+static void gcm_ghash_4bit(u64 Xi[2],const u128 Htable[16],
+				const u8 *inp,size_t len)
+{
+    u128 Z;
+    int cnt;
+    size_t rem, nlo, nhi;
+    const union { long one; char little; } is_endian = {1};
+
+#if 1
+    do {
+	cnt  = 15;
+	nlo  = ((const u8 *)Xi)[15];
+	nlo ^= inp[15];
+	nhi  = nlo>>4;
+	nlo &= 0xf;
+
+	Z.hi = Htable[nlo].hi;
+	Z.lo = Htable[nlo].lo;
+
+	while (1) {
+		rem  = (size_t)Z.lo&0xf;
+		Z.lo = (Z.hi<<60)|(Z.lo>>4);
+		Z.hi = (Z.hi>>4);
+		if (sizeof(size_t)==8)
+			Z.hi ^= rem_4bit[rem];
+		else
+			Z.hi ^= (u64)rem_4bit[rem]<<32;
+
+		Z.hi ^= Htable[nhi].hi;
+		Z.lo ^= Htable[nhi].lo;
+
+		if (--cnt<0)		break;
+
+		nlo  = ((const u8 *)Xi)[cnt];
+		nlo ^= inp[cnt];
+		nhi  = nlo>>4;
+		nlo &= 0xf;
+
+		rem  = (size_t)Z.lo&0xf;
+		Z.lo = (Z.hi<<60)|(Z.lo>>4);
+		Z.hi = (Z.hi>>4);
+		if (sizeof(size_t)==8)
+			Z.hi ^= rem_4bit[rem];
+		else
+			Z.hi ^= (u64)rem_4bit[rem]<<32;
+
+		Z.hi ^= Htable[nlo].hi;
+		Z.lo ^= Htable[nlo].lo;
+	}
+#else
+    /*
+     * Extra 256+16 bytes per-key plus 512 bytes shared tables
+     * [should] give ~50% improvement... One could have PACK()-ed
+     * the rem_8bit even here, but the priority is to minimize
+     * cache footprint...
+     */ 
+    u128 Hshr4[16];	/* Htable shifted right by 4 bits */
+    u8   Hshl4[16];	/* Htable shifted left  by 4 bits */
+    static const unsigned short rem_8bit[256] = {
+	0x0000, 0x01C2, 0x0384, 0x0246, 0x0708, 0x06CA, 0x048C, 0x054E,
+	0x0E10, 0x0FD2, 0x0D94, 0x0C56, 0x0918, 0x08DA, 0x0A9C, 0x0B5E,
+	0x1C20, 0x1DE2, 0x1FA4, 0x1E66, 0x1B28, 0x1AEA, 0x18AC, 0x196E,
+	0x1230, 0x13F2, 0x11B4, 0x1076, 0x1538, 0x14FA, 0x16BC, 0x177E,
+	0x3840, 0x3982, 0x3BC4, 0x3A06, 0x3F48, 0x3E8A, 0x3CCC, 0x3D0E,
+	0x3650, 0x3792, 0x35D4, 0x3416, 0x3158, 0x309A, 0x32DC, 0x331E,
+	0x2460, 0x25A2, 0x27E4, 0x2626, 0x2368, 0x22AA, 0x20EC, 0x212E,
+	0x2A70, 0x2BB2, 0x29F4, 0x2836, 0x2D78, 0x2CBA, 0x2EFC, 0x2F3E,
+	0x7080, 0x7142, 0x7304, 0x72C6, 0x7788, 0x764A, 0x740C, 0x75CE,
+	0x7E90, 0x7F52, 0x7D14, 0x7CD6, 0x7998, 0x785A, 0x7A1C, 0x7BDE,
+	0x6CA0, 0x6D62, 0x6F24, 0x6EE6, 0x6BA8, 0x6A6A, 0x682C, 0x69EE,
+	0x62B0, 0x6372, 0x6134, 0x60F6, 0x65B8, 0x647A, 0x663C, 0x67FE,
+	0x48C0, 0x4902, 0x4B44, 0x4A86, 0x4FC8, 0x4E0A, 0x4C4C, 0x4D8E,
+	0x46D0, 0x4712, 0x4554, 0x4496, 0x41D8, 0x401A, 0x425C, 0x439E,
+	0x54E0, 0x5522, 0x5764, 0x56A6, 0x53E8, 0x522A, 0x506C, 0x51AE,
+	0x5AF0, 0x5B32, 0x5974, 0x58B6, 0x5DF8, 0x5C3A, 0x5E7C, 0x5FBE,
+	0xE100, 0xE0C2, 0xE284, 0xE346, 0xE608, 0xE7CA, 0xE58C, 0xE44E,
+	0xEF10, 0xEED2, 0xEC94, 0xED56, 0xE818, 0xE9DA, 0xEB9C, 0xEA5E,
+	0xFD20, 0xFCE2, 0xFEA4, 0xFF66, 0xFA28, 0xFBEA, 0xF9AC, 0xF86E,
+	0xF330, 0xF2F2, 0xF0B4, 0xF176, 0xF438, 0xF5FA, 0xF7BC, 0xF67E,
+	0xD940, 0xD882, 0xDAC4, 0xDB06, 0xDE48, 0xDF8A, 0xDDCC, 0xDC0E,
+	0xD750, 0xD692, 0xD4D4, 0xD516, 0xD058, 0xD19A, 0xD3DC, 0xD21E,
+	0xC560, 0xC4A2, 0xC6E4, 0xC726, 0xC268, 0xC3AA, 0xC1EC, 0xC02E,
+	0xCB70, 0xCAB2, 0xC8F4, 0xC936, 0xCC78, 0xCDBA, 0xCFFC, 0xCE3E,
+	0x9180, 0x9042, 0x9204, 0x93C6, 0x9688, 0x974A, 0x950C, 0x94CE,
+	0x9F90, 0x9E52, 0x9C14, 0x9DD6, 0x9898, 0x995A, 0x9B1C, 0x9ADE,
+	0x8DA0, 0x8C62, 0x8E24, 0x8FE6, 0x8AA8, 0x8B6A, 0x892C, 0x88EE,
+	0x83B0, 0x8272, 0x8034, 0x81F6, 0x84B8, 0x857A, 0x873C, 0x86FE,
+	0xA9C0, 0xA802, 0xAA44, 0xAB86, 0xAEC8, 0xAF0A, 0xAD4C, 0xAC8E,
+	0xA7D0, 0xA612, 0xA454, 0xA596, 0xA0D8, 0xA11A, 0xA35C, 0xA29E,
+	0xB5E0, 0xB422, 0xB664, 0xB7A6, 0xB2E8, 0xB32A, 0xB16C, 0xB0AE,
+	0xBBF0, 0xBA32, 0xB874, 0xB9B6, 0xBCF8, 0xBD3A, 0xBF7C, 0xBEBE };
+    /*
+     * This pre-processing phase slows down procedure by approximately
+     * same time as it makes each loop spin faster. In other words
+     * single block performance is approximately same as straightforward
+     * "4-bit" implementation, and then it goes only faster...
+     */
+    for (cnt=0; cnt<16; ++cnt) {
+	Z.hi = Htable[cnt].hi;
+	Z.lo = Htable[cnt].lo;
+	Hshr4[cnt].lo = (Z.hi<<60)|(Z.lo>>4);
+	Hshr4[cnt].hi = (Z.hi>>4);
+	Hshl4[cnt]    = (u8)(Z.lo<<4);
+    }
+
+    do {
+	for (Z.lo=0, Z.hi=0, cnt=15; cnt; --cnt) {
+		nlo  = ((const u8 *)Xi)[cnt];
+		nlo ^= inp[cnt];
+		nhi  = nlo>>4;
+		nlo &= 0xf;
+
+		Z.hi ^= Htable[nlo].hi;
+		Z.lo ^= Htable[nlo].lo;
+
+		rem = (size_t)Z.lo&0xff;
+
+		Z.lo = (Z.hi<<56)|(Z.lo>>8);
+		Z.hi = (Z.hi>>8);
+
+		Z.hi ^= Hshr4[nhi].hi;
+		Z.lo ^= Hshr4[nhi].lo;
+		Z.hi ^= (u64)rem_8bit[rem^Hshl4[nhi]]<<48;
+	}
+
+	nlo  = ((const u8 *)Xi)[0];
+	nlo ^= inp[0];
+	nhi  = nlo>>4;
+	nlo &= 0xf;
+
+	Z.hi ^= Htable[nlo].hi;
+	Z.lo ^= Htable[nlo].lo;
+
+	rem = (size_t)Z.lo&0xf;
+
+	Z.lo = (Z.hi<<60)|(Z.lo>>4);
+	Z.hi = (Z.hi>>4);
+
+	Z.hi ^= Htable[nhi].hi;
+	Z.lo ^= Htable[nhi].lo;
+	Z.hi ^= ((u64)rem_8bit[rem<<4])<<48;
+#endif
+
+	if (is_endian.little) {
+#ifdef BSWAP8
+		Xi[0] = BSWAP8(Z.hi);
+		Xi[1] = BSWAP8(Z.lo);
+#else
+		u8 *p = (u8 *)Xi;
+		u32 v;
+		v = (u32)(Z.hi>>32);	PUTU32(p,v);
+		v = (u32)(Z.hi);	PUTU32(p+4,v);
+		v = (u32)(Z.lo>>32);	PUTU32(p+8,v);
+		v = (u32)(Z.lo);	PUTU32(p+12,v);
+#endif
+	}
+	else {
+		Xi[0] = Z.hi;
+		Xi[1] = Z.lo;
+	}
+    } while (inp+=16, len-=16);
+}
+#endif
+#else
+void gcm_gmult_4bit(u64 Xi[2],const u128 Htable[16]);
+void gcm_ghash_4bit(u64 Xi[2],const u128 Htable[16],const u8 *inp,size_t len);
+#endif
+
+#define GCM_MUL(ctx,Xi)   gcm_gmult_4bit(ctx->Xi.u,ctx->Htable)
+#if defined(GHASH_ASM) || !defined(OPENSSL_SMALL_FOOTPRINT)
+#define GHASH(ctx,in,len) gcm_ghash_4bit((ctx)->Xi.u,(ctx)->Htable,in,len)
+/* GHASH_CHUNK is "stride parameter" missioned to mitigate cache
+ * trashing effect. In other words idea is to hash data while it's
+ * still in L1 cache after encryption pass... */
+#define GHASH_CHUNK       (3*1024)
+#endif
+
+#else	/* TABLE_BITS */
+
+static void gcm_gmult_1bit(u64 Xi[2],const u64 H[2])
+{
+	u128 V,Z = { 0,0 };
+	long X;
+	int  i,j;
+	const long *xi = (const long *)Xi;
+	const union { long one; char little; } is_endian = {1};
+
+	V.hi = H[0];	/* H is in host byte order, no byte swapping */
+	V.lo = H[1];
+
+	for (j=0; j<16/sizeof(long); ++j) {
+		if (is_endian.little) {
+			if (sizeof(long)==8) {
+#ifdef BSWAP8
+				X = (long)(BSWAP8(xi[j]));
+#else
+				const u8 *p = (const u8 *)(xi+j);
+				X = (long)((u64)GETU32(p)<<32|GETU32(p+4));
+#endif
+			}
+			else {
+				const u8 *p = (const u8 *)(xi+j);
+				X = (long)GETU32(p);
+			}
+		}
+		else
+			X = xi[j];
+
+		for (i=0; i<8*sizeof(long); ++i, X<<=1) {
+			u64 M = (u64)(X>>(8*sizeof(long)-1));
+			Z.hi ^= V.hi&M;
+			Z.lo ^= V.lo&M;
+
+			REDUCE1BIT(V);
+		}
+	}
+
+	if (is_endian.little) {
+#ifdef BSWAP8
+		Xi[0] = BSWAP8(Z.hi);
+		Xi[1] = BSWAP8(Z.lo);
+#else
+		u8 *p = (u8 *)Xi;
+		u32 v;
+		v = (u32)(Z.hi>>32);	PUTU32(p,v);
+		v = (u32)(Z.hi);	PUTU32(p+4,v);
+		v = (u32)(Z.lo>>32);	PUTU32(p+8,v);
+		v = (u32)(Z.lo);	PUTU32(p+12,v);
+#endif
+	}
+	else {
+		Xi[0] = Z.hi;
+		Xi[1] = Z.lo;
+	}
+}
+#define GCM_MUL(ctx,Xi)	  gcm_gmult_1bit(ctx->Xi.u,ctx->H.u)
+
+#endif
+
+#if	TABLE_BITS==4 && defined(GHASH_ASM)
+# if	!defined(I386_ONLY) && \
+	(defined(__i386)	|| defined(__i386__)	|| \
+	 defined(__x86_64)	|| defined(__x86_64__)	|| \
+	 defined(_M_IX86)	|| defined(_M_AMD64)	|| defined(_M_X64))
+#  define GHASH_ASM_X86_OR_64
+#  define GCM_FUNCREF_4BIT
+extern unsigned int OPENSSL_ia32cap_P[2];
+
+void gcm_init_clmul(u128 Htable[16],const u64 Xi[2]);
+void gcm_gmult_clmul(u64 Xi[2],const u128 Htable[16]);
+void gcm_ghash_clmul(u64 Xi[2],const u128 Htable[16],const u8 *inp,size_t len);
+
+#  if	defined(__i386) || defined(__i386__) || defined(_M_IX86)
+#   define GHASH_ASM_X86
+void gcm_gmult_4bit_mmx(u64 Xi[2],const u128 Htable[16]);
+void gcm_ghash_4bit_mmx(u64 Xi[2],const u128 Htable[16],const u8 *inp,size_t len);
+
+void gcm_gmult_4bit_x86(u64 Xi[2],const u128 Htable[16]);
+void gcm_ghash_4bit_x86(u64 Xi[2],const u128 Htable[16],const u8 *inp,size_t len);
+#  endif
+# elif defined(__arm__) || defined(__arm)
+#  include "arm_arch.h"
+#  if __ARM_ARCH__>=7
+#   define GHASH_ASM_ARM
+#   define GCM_FUNCREF_4BIT
+void gcm_gmult_neon(u64 Xi[2],const u128 Htable[16]);
+void gcm_ghash_neon(u64 Xi[2],const u128 Htable[16],const u8 *inp,size_t len);
+#  endif
+# endif
+#endif
+
+#ifdef GCM_FUNCREF_4BIT
+# undef  GCM_MUL
+# define GCM_MUL(ctx,Xi)	(*gcm_gmult_p)(ctx->Xi.u,ctx->Htable)
+# ifdef GHASH
+#  undef  GHASH
+#  define GHASH(ctx,in,len)	(*gcm_ghash_p)(ctx->Xi.u,ctx->Htable,in,len)
+# endif
+#endif
+
+void CRYPTO_gcm128_init(GCM128_CONTEXT *ctx,void *key,block128_f block)
+{
+	const union { long one; char little; } is_endian = {1};
+
+	memset(ctx,0,sizeof(*ctx));
+	ctx->block = block;
+	ctx->key   = key;
+
+	(*block)(ctx->H.c,ctx->H.c,key);
+
+	if (is_endian.little) {
+		/* H is stored in host byte order */
+#ifdef BSWAP8
+		ctx->H.u[0] = BSWAP8(ctx->H.u[0]);
+		ctx->H.u[1] = BSWAP8(ctx->H.u[1]);
+#else
+		u8 *p = ctx->H.c;
+		u64 hi,lo;
+		hi = (u64)GETU32(p)  <<32|GETU32(p+4);
+		lo = (u64)GETU32(p+8)<<32|GETU32(p+12);
+		ctx->H.u[0] = hi;
+		ctx->H.u[1] = lo;
+#endif
+	}
+
+#if	TABLE_BITS==8
+	gcm_init_8bit(ctx->Htable,ctx->H.u);
+#elif	TABLE_BITS==4
+# if	defined(GHASH_ASM_X86_OR_64)
+#  if	!defined(GHASH_ASM_X86) || defined(OPENSSL_IA32_SSE2)
+	if (OPENSSL_ia32cap_P[0]&(1<<24) &&	/* check FXSR bit */
+	    OPENSSL_ia32cap_P[1]&(1<<1) ) {	/* check PCLMULQDQ bit */
+		gcm_init_clmul(ctx->Htable,ctx->H.u);
+		ctx->gmult = gcm_gmult_clmul;
+		ctx->ghash = gcm_ghash_clmul;
+		return;
+	}
+#  endif
+	gcm_init_4bit(ctx->Htable,ctx->H.u);
+#  if	defined(GHASH_ASM_X86)			/* x86 only */
+	if (OPENSSL_ia32cap_P[0]&(1<<23)) {	/* check MMX bit */
+		ctx->gmult = gcm_gmult_4bit_mmx;
+		ctx->ghash = gcm_ghash_4bit_mmx;
+	} else {
+		ctx->gmult = gcm_gmult_4bit_x86;
+		ctx->ghash = gcm_ghash_4bit_x86;
+	}
+#  else
+	ctx->gmult = gcm_gmult_4bit;
+	ctx->ghash = gcm_ghash_4bit;
+#  endif
+# elif	defined(GHASH_ASM_ARM)
+	if (OPENSSL_armcap_P & ARMV7_NEON) {
+		ctx->gmult = gcm_gmult_neon;
+		ctx->ghash = gcm_ghash_neon;
+	} else {
+		gcm_init_4bit(ctx->Htable,ctx->H.u);
+		ctx->gmult = gcm_gmult_4bit;
+		ctx->ghash = gcm_ghash_4bit;
+	}
+# else
+	gcm_init_4bit(ctx->Htable,ctx->H.u);
+# endif
+#endif
+}
+
+void CRYPTO_gcm128_setiv(GCM128_CONTEXT *ctx,const unsigned char *iv,size_t len)
+{
+	const union { long one; char little; } is_endian = {1};
+	unsigned int ctr;
+#ifdef GCM_FUNCREF_4BIT
+	void (*gcm_gmult_p)(u64 Xi[2],const u128 Htable[16])	= ctx->gmult;
+#endif
+
+	ctx->Yi.u[0]  = 0;
+	ctx->Yi.u[1]  = 0;
+	ctx->Xi.u[0]  = 0;
+	ctx->Xi.u[1]  = 0;
+	ctx->len.u[0] = 0;	/* AAD length */
+	ctx->len.u[1] = 0;	/* message length */
+	ctx->ares = 0;
+	ctx->mres = 0;
+
+	if (len==12) {
+		memcpy(ctx->Yi.c,iv,12);
+		ctx->Yi.c[15]=1;
+		ctr=1;
+	}
+	else {
+		size_t i;
+		u64 len0 = len;
+
+		while (len>=16) {
+			for (i=0; i<16; ++i) ctx->Yi.c[i] ^= iv[i];
+			GCM_MUL(ctx,Yi);
+			iv += 16;
+			len -= 16;
+		}
+		if (len) {
+			for (i=0; i<len; ++i) ctx->Yi.c[i] ^= iv[i];
+			GCM_MUL(ctx,Yi);
+		}
+		len0 <<= 3;
+		if (is_endian.little) {
+#ifdef BSWAP8
+			ctx->Yi.u[1]  ^= BSWAP8(len0);
+#else
+			ctx->Yi.c[8]  ^= (u8)(len0>>56);
+			ctx->Yi.c[9]  ^= (u8)(len0>>48);
+			ctx->Yi.c[10] ^= (u8)(len0>>40);
+			ctx->Yi.c[11] ^= (u8)(len0>>32);
+			ctx->Yi.c[12] ^= (u8)(len0>>24);
+			ctx->Yi.c[13] ^= (u8)(len0>>16);
+			ctx->Yi.c[14] ^= (u8)(len0>>8);
+			ctx->Yi.c[15] ^= (u8)(len0);
+#endif
+		}
+		else
+			ctx->Yi.u[1]  ^= len0;
+
+		GCM_MUL(ctx,Yi);
+
+		if (is_endian.little)
+			ctr = GETU32(ctx->Yi.c+12);
+		else
+			ctr = ctx->Yi.d[3];
+	}
+
+	(*ctx->block)(ctx->Yi.c,ctx->EK0.c,ctx->key);
+	++ctr;
+	if (is_endian.little)
+		PUTU32(ctx->Yi.c+12,ctr);
+	else
+		ctx->Yi.d[3] = ctr;
+}
+
+int CRYPTO_gcm128_aad(GCM128_CONTEXT *ctx,const unsigned char *aad,size_t len)
+{
+	size_t i;
+	unsigned int n;
+	u64 alen = ctx->len.u[0];
+#ifdef GCM_FUNCREF_4BIT
+	void (*gcm_gmult_p)(u64 Xi[2],const u128 Htable[16])	= ctx->gmult;
+# ifdef GHASH
+	void (*gcm_ghash_p)(u64 Xi[2],const u128 Htable[16],
+				const u8 *inp,size_t len)	= ctx->ghash;
+# endif
+#endif
+
+	if (ctx->len.u[1]) return -2;
+
+	alen += len;
+	if (alen>(U64(1)<<61) || (sizeof(len)==8 && alen<len))
+		return -1;
+	ctx->len.u[0] = alen;
+
+	n = ctx->ares;
+	if (n) {
+		while (n && len) {
+			ctx->Xi.c[n] ^= *(aad++);
+			--len;
+			n = (n+1)%16;
+		}
+		if (n==0) GCM_MUL(ctx,Xi);
+		else {
+			ctx->ares = n;
+			return 0;
+		}
+	}
+
+#ifdef GHASH
+	if ((i = (len&(size_t)-16))) {
+		GHASH(ctx,aad,i);
+		aad += i;
+		len -= i;
+	}
+#else
+	while (len>=16) {
+		for (i=0; i<16; ++i) ctx->Xi.c[i] ^= aad[i];
+		GCM_MUL(ctx,Xi);
+		aad += 16;
+		len -= 16;
+	}
+#endif
+	if (len) {
+		n = (unsigned int)len;
+		for (i=0; i<len; ++i) ctx->Xi.c[i] ^= aad[i];
+	}
+
+	ctx->ares = n;
+	return 0;
+}
+
+int CRYPTO_gcm128_encrypt(GCM128_CONTEXT *ctx,
+		const unsigned char *in, unsigned char *out,
+		size_t len)
+{
+	const union { long one; char little; } is_endian = {1};
+	unsigned int n, ctr;
+	size_t i;
+	u64        mlen  = ctx->len.u[1];
+	block128_f block = ctx->block;
+	void      *key   = ctx->key;
+#ifdef GCM_FUNCREF_4BIT
+	void (*gcm_gmult_p)(u64 Xi[2],const u128 Htable[16])	= ctx->gmult;
+# ifdef GHASH
+	void (*gcm_ghash_p)(u64 Xi[2],const u128 Htable[16],
+				const u8 *inp,size_t len)	= ctx->ghash;
+# endif
+#endif
+
+#if 0
+	n = (unsigned int)mlen%16; /* alternative to ctx->mres */
+#endif
+	mlen += len;
+	if (mlen>((U64(1)<<36)-32) || (sizeof(len)==8 && mlen<len))
+		return -1;
+	ctx->len.u[1] = mlen;
+
+	if (ctx->ares) {
+		/* First call to encrypt finalizes GHASH(AAD) */
+		GCM_MUL(ctx,Xi);
+		ctx->ares = 0;
+	}
+
+	if (is_endian.little)
+		ctr = GETU32(ctx->Yi.c+12);
+	else
+		ctr = ctx->Yi.d[3];
+
+	n = ctx->mres;
+#if !defined(OPENSSL_SMALL_FOOTPRINT)
+	if (16%sizeof(size_t) == 0) do {	/* always true actually */
+		if (n) {
+			while (n && len) {
+				ctx->Xi.c[n] ^= *(out++) = *(in++)^ctx->EKi.c[n];
+				--len;
+				n = (n+1)%16;
+			}
+			if (n==0) GCM_MUL(ctx,Xi);
+			else {
+				ctx->mres = n;
+				return 0;
+			}
+		}
+#if defined(STRICT_ALIGNMENT)
+		if (((size_t)in|(size_t)out)%sizeof(size_t) != 0)
+			break;
+#endif
+#if defined(GHASH) && defined(GHASH_CHUNK)
+		while (len>=GHASH_CHUNK) {
+		    size_t j=GHASH_CHUNK;
+
+		    while (j) {
+			(*block)(ctx->Yi.c,ctx->EKi.c,key);
+			++ctr;
+			if (is_endian.little)
+				PUTU32(ctx->Yi.c+12,ctr);
+			else
+				ctx->Yi.d[3] = ctr;
+			for (i=0; i<16; i+=sizeof(size_t))
+				*(size_t *)(out+i) =
+				*(size_t *)(in+i)^*(size_t *)(ctx->EKi.c+i);
+			out += 16;
+			in  += 16;
+			j   -= 16;
+		    }
+		    GHASH(ctx,out-GHASH_CHUNK,GHASH_CHUNK);
+		    len -= GHASH_CHUNK;
+		}
+		if ((i = (len&(size_t)-16))) {
+		    size_t j=i;
+
+		    while (len>=16) {
+			(*block)(ctx->Yi.c,ctx->EKi.c,key);
+			++ctr;
+			if (is_endian.little)
+				PUTU32(ctx->Yi.c+12,ctr);
+			else
+				ctx->Yi.d[3] = ctr;
+			for (i=0; i<16; i+=sizeof(size_t))
+				*(size_t *)(out+i) =
+				*(size_t *)(in+i)^*(size_t *)(ctx->EKi.c+i);
+			out += 16;
+			in  += 16;
+			len -= 16;
+		    }
+		    GHASH(ctx,out-j,j);
+		}
+#else
+		while (len>=16) {
+			(*block)(ctx->Yi.c,ctx->EKi.c,key);
+			++ctr;
+			if (is_endian.little)
+				PUTU32(ctx->Yi.c+12,ctr);
+			else
+				ctx->Yi.d[3] = ctr;
+			for (i=0; i<16; i+=sizeof(size_t))
+				*(size_t *)(ctx->Xi.c+i) ^=
+				*(size_t *)(out+i) =
+				*(size_t *)(in+i)^*(size_t *)(ctx->EKi.c+i);
+			GCM_MUL(ctx,Xi);
+			out += 16;
+			in  += 16;
+			len -= 16;
+		}
+#endif
+		if (len) {
+			(*block)(ctx->Yi.c,ctx->EKi.c,key);
+			++ctr;
+			if (is_endian.little)
+				PUTU32(ctx->Yi.c+12,ctr);
+			else
+				ctx->Yi.d[3] = ctr;
+			while (len--) {
+				ctx->Xi.c[n] ^= out[n] = in[n]^ctx->EKi.c[n];
+				++n;
+			}
+		}
+
+		ctx->mres = n;
+		return 0;
+	} while(0);
+#endif
+	for (i=0;i<len;++i) {
+		if (n==0) {
+			(*block)(ctx->Yi.c,ctx->EKi.c,key);
+			++ctr;
+			if (is_endian.little)
+				PUTU32(ctx->Yi.c+12,ctr);
+			else
+				ctx->Yi.d[3] = ctr;
+		}
+		ctx->Xi.c[n] ^= out[i] = in[i]^ctx->EKi.c[n];
+		n = (n+1)%16;
+		if (n==0)
+			GCM_MUL(ctx,Xi);
+	}
+
+	ctx->mres = n;
+	return 0;
+}
+
+int CRYPTO_gcm128_decrypt(GCM128_CO