Back to the standard "app" module.

This return to "app" instead of "bitmask_android" is due to this reading: https://developer.android.com/sdk/installing/studio-build.html#projectStructure
I'll have to tweak the final apk name in build.gradle.

1 files changed, 940 insertions, 0 deletions

diff --git a/app/openssl/crypto/ec/ec_mult.c b/app/openssl/crypto/ec/ec_mult.c
new file mode 100644
index 00000000..19f21675
--- /dev/null
+++ b/app/openssl/crypto/ec/ec_mult.c
@@ -0,0 +1,940 @@
+/* crypto/ec/ec_mult.c */
+/*
+ * Originally written by Bodo Moeller and Nils Larsch for the OpenSSL project.
+ */
+/* ====================================================================
+ * Copyright (c) 1998-2007 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.
+ * ====================================================================
+ *
+ * This product includes cryptographic software written by Eric Young
+ * (eay@cryptsoft.com).  This product includes software written by Tim
+ * Hudson (tjh@cryptsoft.com).
+ *
+ */
+/* ====================================================================
+ * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
+ * Portions of this software developed by SUN MICROSYSTEMS, INC.,
+ * and contributed to the OpenSSL project.
+ */
+
+#include <string.h>
+
+#include <openssl/err.h>
+
+#include "ec_lcl.h"
+
+
+/*
+ * This file implements the wNAF-based interleaving multi-exponentation method
+ * (<URL:http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/moeller.html#multiexp>);
+ * for multiplication with precomputation, we use wNAF splitting
+ * (<URL:http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/moeller.html#fastexp>).
+ */
+
+
+
+
+/* structure for precomputed multiples of the generator */
+typedef struct ec_pre_comp_st {
+	const EC_GROUP *group; /* parent EC_GROUP object */
+	size_t blocksize;      /* block size for wNAF splitting */
+	size_t numblocks;      /* max. number of blocks for which we have precomputation */
+	size_t w;              /* window size */
+	EC_POINT **points;     /* array with pre-calculated multiples of generator:
+	                        * 'num' pointers to EC_POINT objects followed by a NULL */
+	size_t num;            /* numblocks * 2^(w-1) */
+	int references;
+} EC_PRE_COMP;
+ 
+/* functions to manage EC_PRE_COMP within the EC_GROUP extra_data framework */
+static void *ec_pre_comp_dup(void *);
+static void ec_pre_comp_free(void *);
+static void ec_pre_comp_clear_free(void *);
+
+static EC_PRE_COMP *ec_pre_comp_new(const EC_GROUP *group)
+	{
+	EC_PRE_COMP *ret = NULL;
+
+	if (!group)
+		return NULL;
+
+	ret = (EC_PRE_COMP *)OPENSSL_malloc(sizeof(EC_PRE_COMP));
+	if (!ret)
+		{
+		ECerr(EC_F_EC_PRE_COMP_NEW, ERR_R_MALLOC_FAILURE);
+		return ret;
+		}
+	ret->group = group;
+	ret->blocksize = 8; /* default */
+	ret->numblocks = 0;
+	ret->w = 4; /* default */
+	ret->points = NULL;
+	ret->num = 0;
+	ret->references = 1;
+	return ret;
+	}
+
+static void *ec_pre_comp_dup(void *src_)
+	{
+	EC_PRE_COMP *src = src_;
+
+	/* no need to actually copy, these objects never change! */
+
+	CRYPTO_add(&src->references, 1, CRYPTO_LOCK_EC_PRE_COMP);
+
+	return src_;
+	}
+
+static void ec_pre_comp_free(void *pre_)
+	{
+	int i;
+	EC_PRE_COMP *pre = pre_;
+
+	if (!pre)
+		return;
+
+	i = CRYPTO_add(&pre->references, -1, CRYPTO_LOCK_EC_PRE_COMP);
+	if (i > 0)
+		return;
+
+	if (pre->points)
+		{
+		EC_POINT **p;
+
+		for (p = pre->points; *p != NULL; p++)
+			EC_POINT_free(*p);
+		OPENSSL_free(pre->points);
+		}
+	OPENSSL_free(pre);
+	}
+
+static void ec_pre_comp_clear_free(void *pre_)
+	{
+	int i;
+	EC_PRE_COMP *pre = pre_;
+
+	if (!pre)
+		return;
+
+	i = CRYPTO_add(&pre->references, -1, CRYPTO_LOCK_EC_PRE_COMP);
+	if (i > 0)
+		return;
+
+	if (pre->points)
+		{
+		EC_POINT **p;
+
+		for (p = pre->points; *p != NULL; p++)
+			{
+			EC_POINT_clear_free(*p);
+			OPENSSL_cleanse(p, sizeof *p);
+			}
+		OPENSSL_free(pre->points);
+		}
+	OPENSSL_cleanse(pre, sizeof *pre);
+	OPENSSL_free(pre);
+	}
+
+
+
+
+/* Determine the modified width-(w+1) Non-Adjacent Form (wNAF) of 'scalar'.
+ * This is an array  r[]  of values that are either zero or odd with an
+ * absolute value less than  2^w  satisfying
+ *     scalar = \sum_j r[j]*2^j
+ * where at most one of any  w+1  consecutive digits is non-zero
+ * with the exception that the most significant digit may be only
+ * w-1 zeros away from that next non-zero digit.
+ */
+static signed char *compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len)
+	{
+	int window_val;
+	int ok = 0;
+	signed char *r = NULL;
+	int sign = 1;
+	int bit, next_bit, mask;
+	size_t len = 0, j;
+	
+	if (BN_is_zero(scalar))
+		{
+		r = OPENSSL_malloc(1);
+		if (!r)
+			{
+			ECerr(EC_F_COMPUTE_WNAF, ERR_R_MALLOC_FAILURE);
+			goto err;
+			}
+		r[0] = 0;
+		*ret_len = 1;
+		return r;
+		}
+		
+	if (w <= 0 || w > 7) /* 'signed char' can represent integers with absolute values less than 2^7 */
+		{
+		ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
+		goto err;
+		}
+	bit = 1 << w; /* at most 128 */
+	next_bit = bit << 1; /* at most 256 */
+	mask = next_bit - 1; /* at most 255 */
+
+	if (BN_is_negative(scalar))
+		{
+		sign = -1;
+		}
+
+	if (scalar->d == NULL || scalar->top == 0)
+		{
+		ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
+		goto err;
+		}
+
+	len = BN_num_bits(scalar);
+	r = OPENSSL_malloc(len + 1); /* modified wNAF may be one digit longer than binary representation
+	                              * (*ret_len will be set to the actual length, i.e. at most
+	                              * BN_num_bits(scalar) + 1) */
+	if (r == NULL)
+		{
+		ECerr(EC_F_COMPUTE_WNAF, ERR_R_MALLOC_FAILURE);
+		goto err;
+		}
+	window_val = scalar->d[0] & mask;
+	j = 0;
+	while ((window_val != 0) || (j + w + 1 < len)) /* if j+w+1 >= len, window_val will not increase */
+		{
+		int digit = 0;
+
+		/* 0 <= window_val <= 2^(w+1) */
+
+		if (window_val & 1)
+			{
+			/* 0 < window_val < 2^(w+1) */
+
+			if (window_val & bit)
+				{
+				digit = window_val - next_bit; /* -2^w < digit < 0 */
+
+#if 1 /* modified wNAF */
+				if (j + w + 1 >= len)
+					{
+					/* special case for generating modified wNAFs:
+					 * no new bits will be added into window_val,
+					 * so using a positive digit here will decrease
+					 * the total length of the representation */
+					
+					digit = window_val & (mask >> 1); /* 0 < digit < 2^w */
+					}
+#endif
+				}
+			else
+				{
+				digit = window_val; /* 0 < digit < 2^w */
+				}
+			
+			if (digit <= -bit || digit >= bit || !(digit & 1))
+				{
+				ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
+				goto err;
+				}
+
+			window_val -= digit;
+
+			/* now window_val is 0 or 2^(w+1) in standard wNAF generation;
+			 * for modified window NAFs, it may also be 2^w
+			 */
+			if (window_val != 0 && window_val != next_bit && window_val != bit)
+				{
+				ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
+				goto err;
+				}
+			}
+
+		r[j++] = sign * digit;
+
+		window_val >>= 1;
+		window_val += bit * BN_is_bit_set(scalar, j + w);
+
+		if (window_val > next_bit)
+			{
+			ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
+			goto err;
+			}
+		}
+
+	if (j > len + 1)
+		{
+		ECerr(EC_F_COMPUTE_WNAF, ERR_R_INTERNAL_ERROR);
+		goto err;
+		}
+	len = j;
+	ok = 1;
+
+ err:
+	if (!ok)
+		{
+		OPENSSL_free(r);
+		r = NULL;
+		}
+	if (ok)
+		*ret_len = len;
+	return r;
+	}
+
+
+/* TODO: table should be optimised for the wNAF-based implementation,
+ *       sometimes smaller windows will give better performance
+ *       (thus the boundaries should be increased)
+ */
+#define EC_window_bits_for_scalar_size(b) \
+		((size_t) \
+		 ((b) >= 2000 ? 6 : \
+		  (b) >=  800 ? 5 : \
+		  (b) >=  300 ? 4 : \
+		  (b) >=   70 ? 3 : \
+		  (b) >=   20 ? 2 : \
+		  1))
+
+/* Compute
+ *      \sum scalars[i]*points[i],
+ * also including
+ *      scalar*generator
+ * in the addition if scalar != NULL
+ */
+int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
+	size_t num, const EC_POINT *points[], const BIGNUM *scalars[], BN_CTX *ctx)
+	{
+	BN_CTX *new_ctx = NULL;
+	const EC_POINT *generator = NULL;
+	EC_POINT *tmp = NULL;
+	size_t totalnum;
+	size_t blocksize = 0, numblocks = 0; /* for wNAF splitting */
+	size_t pre_points_per_block = 0;
+	size_t i, j;
+	int k;
+	int r_is_inverted = 0;
+	int r_is_at_infinity = 1;
+	size_t *wsize = NULL; /* individual window sizes */
+	signed char **wNAF = NULL; /* individual wNAFs */
+	size_t *wNAF_len = NULL;
+	size_t max_len = 0;
+	size_t num_val;
+	EC_POINT **val = NULL; /* precomputation */
+	EC_POINT **v;
+	EC_POINT ***val_sub = NULL; /* pointers to sub-arrays of 'val' or 'pre_comp->points' */
+	const EC_PRE_COMP *pre_comp = NULL;
+	int num_scalar = 0; /* flag: will be set to 1 if 'scalar' must be treated like other scalars,
+	                     * i.e. precomputation is not available */
+	int ret = 0;
+	
+	if (group->meth != r->meth)
+		{
+		ECerr(EC_F_EC_WNAF_MUL, EC_R_INCOMPATIBLE_OBJECTS);
+		return 0;
+		}
+
+	if ((scalar == NULL) && (num == 0))
+		{
+		return EC_POINT_set_to_infinity(group, r);
+		}
+
+	for (i = 0; i < num; i++)
+		{
+		if (group->meth != points[i]->meth)
+			{
+			ECerr(EC_F_EC_WNAF_MUL, EC_R_INCOMPATIBLE_OBJECTS);
+			return 0;
+			}
+		}
+
+	if (ctx == NULL)
+		{
+		ctx = new_ctx = BN_CTX_new();
+		if (ctx == NULL)
+			goto err;
+		}
+
+	if (scalar != NULL)
+		{
+		generator = EC_GROUP_get0_generator(group);
+		if (generator == NULL)
+			{
+			ECerr(EC_F_EC_WNAF_MUL, EC_R_UNDEFINED_GENERATOR);
+			goto err;
+			}
+		
+		/* look if we can use precomputed multiples of generator */
+
+		pre_comp = EC_EX_DATA_get_data(group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free);
+
+		if (pre_comp && pre_comp->numblocks && (EC_POINT_cmp(group, generator, pre_comp->points[0], ctx) == 0))
+			{
+			blocksize = pre_comp->blocksize;
+
+			/* determine maximum number of blocks that wNAF splitting may yield
+			 * (NB: maximum wNAF length is bit length plus one) */
+			numblocks = (BN_num_bits(scalar) / blocksize) + 1;
+
+			/* we cannot use more blocks than we have precomputation for */
+			if (numblocks > pre_comp->numblocks)
+				numblocks = pre_comp->numblocks;
+
+			pre_points_per_block = (size_t)1 << (pre_comp->w - 1);
+
+			/* check that pre_comp looks sane */
+			if (pre_comp->num != (pre_comp->numblocks * pre_points_per_block))
+				{
+				ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR);
+				goto err;
+				}
+			}
+		else
+			{
+			/* can't use precomputation */
+			pre_comp = NULL;
+			numblocks = 1;
+			num_scalar = 1; /* treat 'scalar' like 'num'-th element of 'scalars' */
+			}
+		}
+	
+	totalnum = num + numblocks;
+
+	wsize    = OPENSSL_malloc(totalnum * sizeof wsize[0]);
+	wNAF_len = OPENSSL_malloc(totalnum * sizeof wNAF_len[0]);
+	wNAF     = OPENSSL_malloc((totalnum + 1) * sizeof wNAF[0]); /* includes space for pivot */
+	val_sub  = OPENSSL_malloc(totalnum * sizeof val_sub[0]);
+		 
+	if (!wsize || !wNAF_len || !wNAF || !val_sub)
+		{
+		ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE);
+		goto err;
+		}
+
+	wNAF[0] = NULL;	/* preliminary pivot */
+
+	/* num_val will be the total number of temporarily precomputed points */
+	num_val = 0;
+
+	for (i = 0; i < num + num_scalar; i++)
+		{
+		size_t bits;
+
+		bits = i < num ? BN_num_bits(scalars[i]) : BN_num_bits(scalar);
+		wsize[i] = EC_window_bits_for_scalar_size(bits);
+		num_val += (size_t)1 << (wsize[i] - 1);
+		wNAF[i + 1] = NULL; /* make sure we always have a pivot */
+		wNAF[i] = compute_wNAF((i < num ? scalars[i] : scalar), wsize[i], &wNAF_len[i]);
+		if (wNAF[i] == NULL)
+			goto err;
+		if (wNAF_len[i] > max_len)
+			max_len = wNAF_len[i];
+		}
+
+	if (numblocks)
+		{
+		/* we go here iff scalar != NULL */
+		
+		if (pre_comp == NULL)
+			{
+			if (num_scalar != 1)
+				{
+				ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR);
+				goto err;
+				}
+			/* we have already generated a wNAF for 'scalar' */
+			}
+		else
+			{
+			signed char *tmp_wNAF = NULL;
+			size_t tmp_len = 0;
+			
+			if (num_scalar != 0)
+				{
+				ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR);
+				goto err;
+				}
+
+			/* use the window size for which we have precomputation */
+			wsize[num] = pre_comp->w;
+			tmp_wNAF = compute_wNAF(scalar, wsize[num], &tmp_len);
+			if (!tmp_wNAF)
+				goto err;
+
+			if (tmp_len <= max_len)
+				{
+				/* One of the other wNAFs is at least as long
+				 * as the wNAF belonging to the generator,
+				 * so wNAF splitting will not buy us anything. */
+
+				numblocks = 1;
+				totalnum = num + 1; /* don't use wNAF splitting */
+				wNAF[num] = tmp_wNAF;
+				wNAF[num + 1] = NULL;
+				wNAF_len[num] = tmp_len;
+				if (tmp_len > max_len)
+					max_len = tmp_len;
+				/* pre_comp->points starts with the points that we need here: */
+				val_sub[num] = pre_comp->points;
+				}
+			else
+				{
+				/* don't include tmp_wNAF directly into wNAF array
+				 * - use wNAF splitting and include the blocks */
+
+				signed char *pp;
+				EC_POINT **tmp_points;
+				
+				if (tmp_len < numblocks * blocksize)
+					{
+					/* possibly we can do with fewer blocks than estimated */
+					numblocks = (tmp_len + blocksize - 1) / blocksize;
+					if (numblocks > pre_comp->numblocks)
+						{
+						ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR);
+						goto err;
+						}
+					totalnum = num + numblocks;
+					}
+				
+				/* split wNAF in 'numblocks' parts */
+				pp = tmp_wNAF;
+				tmp_points = pre_comp->points;
+
+				for (i = num; i < totalnum; i++)
+					{
+					if (i < totalnum - 1)
+						{
+						wNAF_len[i] = blocksize;
+						if (tmp_len < blocksize)
+							{
+							ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR);
+							goto err;
+							}
+						tmp_len -= blocksize;
+						}
+					else
+						/* last block gets whatever is left
+						 * (this could be more or less than 'blocksize'!) */
+						wNAF_len[i] = tmp_len;
+					
+					wNAF[i + 1] = NULL;
+					wNAF[i] = OPENSSL_malloc(wNAF_len[i]);
+					if (wNAF[i] == NULL)
+						{
+						ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE);
+						OPENSSL_free(tmp_wNAF);
+						goto err;
+						}
+					memcpy(wNAF[i], pp, wNAF_len[i]);
+					if (wNAF_len[i] > max_len)
+						max_len = wNAF_len[i];
+
+					if (*tmp_points == NULL)
+						{
+						ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR);
+						OPENSSL_free(tmp_wNAF);
+						goto err;
+						}
+					val_sub[i] = tmp_points;
+					tmp_points += pre_points_per_block;
+					pp += blocksize;
+					}
+				OPENSSL_free(tmp_wNAF);
+				}
+			}
+		}
+
+	/* All points we precompute now go into a single array 'val'.
+	 * 'val_sub[i]' is a pointer to the subarray for the i-th point,
+	 * or to a subarray of 'pre_comp->points' if we already have precomputation. */
+	val = OPENSSL_malloc((num_val + 1) * sizeof val[0]);
+	if (val == NULL)
+		{
+		ECerr(EC_F_EC_WNAF_MUL, ERR_R_MALLOC_FAILURE);
+		goto err;
+		}
+	val[num_val] = NULL; /* pivot element */
+
+	/* allocate points for precomputation */
+	v = val;
+	for (i = 0; i < num + num_scalar; i++)
+		{
+		val_sub[i] = v;
+		for (j = 0; j < ((size_t)1 << (wsize[i] - 1)); j++)
+			{
+			*v = EC_POINT_new(group);
+			if (*v == NULL) goto err;
+			v++;
+			}
+		}
+	if (!(v == val + num_val))
+		{
+		ECerr(EC_F_EC_WNAF_MUL, ERR_R_INTERNAL_ERROR);
+		goto err;
+		}
+
+	if (!(tmp = EC_POINT_new(group)))
+		goto err;
+
+	/* prepare precomputed values:
+	 *    val_sub[i][0] :=     points[i]
+	 *    val_sub[i][1] := 3 * points[i]
+	 *    val_sub[i][2] := 5 * points[i]
+	 *    ...
+	 */
+	for (i = 0; i < num + num_scalar; i++)
+		{
+		if (i < num)
+			{
+			if (!EC_POINT_copy(val_sub[i][0], points[i])) goto err;
+			}
+		else
+			{
+			if (!EC_POINT_copy(val_sub[i][0], generator)) goto err;
+			}
+
+		if (wsize[i] > 1)
+			{
+			if (!EC_POINT_dbl(group, tmp, val_sub[i][0], ctx)) goto err;
+			for (j = 1; j < ((size_t)1 << (wsize[i] - 1)); j++)
+				{
+				if (!EC_POINT_add(group, val_sub[i][j], val_sub[i][j - 1], tmp, ctx)) goto err;
+				}
+			}
+		}
+
+#if 1 /* optional; EC_window_bits_for_scalar_size assumes we do this step */
+	if (!EC_POINTs_make_affine(group, num_val, val, ctx))
+		goto err;
+#endif
+
+	r_is_at_infinity = 1;
+
+	for (k = max_len - 1; k >= 0; k--)
+		{
+		if (!r_is_at_infinity)
+			{
+			if (!EC_POINT_dbl(group, r, r, ctx)) goto err;
+			}
+		
+		for (i = 0; i < totalnum; i++)
+			{
+			if (wNAF_len[i] > (size_t)k)
+				{
+				int digit = wNAF[i][k];
+				int is_neg;
+
+				if (digit) 
+					{
+					is_neg = digit < 0;
+
+					if (is_neg)
+						digit = -digit;
+
+					if (is_neg != r_is_inverted)
+						{
+						if (!r_is_at_infinity)
+							{
+							if (!EC_POINT_invert(group, r, ctx)) goto err;
+							}
+						r_is_inverted = !r_is_inverted;
+						}
+
+					/* digit > 0 */
+
+					if (r_is_at_infinity)
+						{
+						if (!EC_POINT_copy(r, val_sub[i][digit >> 1])) goto err;
+						r_is_at_infinity = 0;
+						}
+					else
+						{
+						if (!EC_POINT_add(group, r, r, val_sub[i][digit >> 1], ctx)) goto err;
+						}
+					}
+				}
+			}
+		}
+
+	if (r_is_at_infinity)
+		{
+		if (!EC_POINT_set_to_infinity(group, r)) goto err;
+		}
+	else
+		{
+		if (r_is_inverted)
+			if (!EC_POINT_invert(group, r, ctx)) goto err;
+		}
+	
+	ret = 1;
+
+ err:
+	if (new_ctx != NULL)
+		BN_CTX_free(new_ctx);
+	if (tmp != NULL)
+		EC_POINT_free(tmp);
+	if (wsize != NULL)
+		OPENSSL_free(wsize);
+	if (wNAF_len != NULL)
+		OPENSSL_free(wNAF_len);
+	if (wNAF != NULL)
+		{
+		signed char **w;
+		
+		for (w = wNAF; *w != NULL; w++)
+			OPENSSL_free(*w);
+		
+		OPENSSL_free(wNAF);
+		}
+	if (val != NULL)
+		{
+		for (v = val; *v != NULL; v++)
+			EC_POINT_clear_free(*v);
+
+		OPENSSL_free(val);
+		}
+	if (val_sub != NULL)
+		{
+		OPENSSL_free(val_sub);
+		}
+	return ret;
+	}
+
+
+/* ec_wNAF_precompute_mult()
+ * creates an EC_PRE_COMP object with preprecomputed multiples of the generator
+ * for use with wNAF splitting as implemented in ec_wNAF_mul().
+ * 
+ * 'pre_comp->points' is an array of multiples of the generator
+ * of the following form:
+ * points[0] =     generator;
+ * points[1] = 3 * generator;
+ * ...
+ * points[2^(w-1)-1] =     (2^(w-1)-1) * generator;
+ * points[2^(w-1)]   =     2^blocksize * generator;
+ * points[2^(w-1)+1] = 3 * 2^blocksize * generator;
+ * ...
+ * points[2^(w-1)*(numblocks-1)-1] = (2^(w-1)) *  2^(blocksize*(numblocks-2)) * generator
+ * points[2^(w-1)*(numblocks-1)]   =              2^(blocksize*(numblocks-1)) * generator
+ * ...
+ * points[2^(w-1)*numblocks-1]     = (2^(w-1)) *  2^(blocksize*(numblocks-1)) * generator
+ * points[2^(w-1)*numblocks]       = NULL
+ */
+int ec_wNAF_precompute_mult(EC_GROUP *group, BN_CTX *ctx)
+	{
+	const EC_POINT *generator;
+	EC_POINT *tmp_point = NULL, *base = NULL, **var;
+	BN_CTX *new_ctx = NULL;
+	BIGNUM *order;
+	size_t i, bits, w, pre_points_per_block, blocksize, numblocks, num;
+	EC_POINT **points = NULL;
+	EC_PRE_COMP *pre_comp;
+	int ret = 0;
+
+	/* if there is an old EC_PRE_COMP object, throw it away */
+	EC_EX_DATA_free_data(&group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free);
+
+	if ((pre_comp = ec_pre_comp_new(group)) == NULL)
+		return 0;
+
+	generator = EC_GROUP_get0_generator(group);
+	if (generator == NULL)
+		{
+		ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, EC_R_UNDEFINED_GENERATOR);
+		goto err;
+		}
+
+	if (ctx == NULL)
+		{
+		ctx = new_ctx = BN_CTX_new();
+		if (ctx == NULL)
+			goto err;
+		}
+	
+	BN_CTX_start(ctx);
+	order = BN_CTX_get(ctx);
+	if (order == NULL) goto err;
+	
+	if (!EC_GROUP_get_order(group, order, ctx)) goto err;		
+	if (BN_is_zero(order))
+		{
+		ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, EC_R_UNKNOWN_ORDER);
+		goto err;
+		}
+
+	bits = BN_num_bits(order);
+	/* The following parameters mean we precompute (approximately)
+	 * one point per bit.
+	 *
+	 * TBD: The combination  8, 4  is perfect for 160 bits; for other
+	 * bit lengths, other parameter combinations might provide better
+	 * efficiency.
+	 */
+	blocksize = 8;
+	w = 4;
+	if (EC_window_bits_for_scalar_size(bits) > w)
+		{
+		/* let's not make the window too small ... */
+		w = EC_window_bits_for_scalar_size(bits);
+		}
+
+	numblocks = (bits + blocksize - 1) / blocksize; /* max. number of blocks to use for wNAF splitting */
+	
+	pre_points_per_block = (size_t)1 << (w - 1);
+	num = pre_points_per_block * numblocks; /* number of points to compute and store */
+
+	points = OPENSSL_malloc(sizeof (EC_POINT*)*(num + 1));
+	if (!points)
+		{
+		ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_MALLOC_FAILURE);
+		goto err;
+		}
+
+	var = points;
+	var[num] = NULL; /* pivot */
+	for (i = 0; i < num; i++)
+		{
+		if ((var[i] = EC_POINT_new(group)) == NULL)
+			{
+			ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_MALLOC_FAILURE);
+			goto err;
+			}
+		}
+
+	if (!(tmp_point = EC_POINT_new(group)) || !(base = EC_POINT_new(group)))
+		{
+		ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_MALLOC_FAILURE);
+		goto err;
+		}	
+	
+	if (!EC_POINT_copy(base, generator))
+		goto err;
+	
+	/* do the precomputation */
+	for (i = 0; i < numblocks; i++)
+		{
+		size_t j;
+
+		if (!EC_POINT_dbl(group, tmp_point, base, ctx))
+			goto err;
+
+		if (!EC_POINT_copy(*var++, base))
+			goto err;
+
+		for (j = 1; j < pre_points_per_block; j++, var++)
+			{
+			/* calculate odd multiples of the current base point */
+			if (!EC_POINT_add(group, *var, tmp_point, *(var - 1), ctx))
+				goto err;
+			}
+
+		if (i < numblocks - 1)
+			{
+			/* get the next base (multiply current one by 2^blocksize) */
+			size_t k;
+
+			if (blocksize <= 2)
+				{
+				ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT, ERR_R_INTERNAL_ERROR);
+				goto err;
+				}				
+
+			if (!EC_POINT_dbl(group, base, tmp_point, ctx))
+				goto err;
+			for (k = 2; k < blocksize; k++)
+				{
+				if (!EC_POINT_dbl(group,base,base,ctx))
+					goto err;
+				}
+			}
+ 		}
+
+	if (!EC_POINTs_make_affine(group, num, points, ctx))
+		goto err;
+	
+	pre_comp->group = group;
+	pre_comp->blocksize = blocksize;
+	pre_comp->numblocks = numblocks;
+	pre_comp->w = w;
+	pre_comp->points = points;
+	points = NULL;
+	pre_comp->num = num;
+
+	if (!EC_EX_DATA_set_data(&group->extra_data, pre_comp,
+		ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free))
+		goto err;
+	pre_comp = NULL;
+
+	ret = 1;
+ err:
+	if (ctx != NULL)
+		BN_CTX_end(ctx);
+	if (new_ctx != NULL)
+		BN_CTX_free(new_ctx);
+	if (pre_comp)
+		ec_pre_comp_free(pre_comp);
+	if (points)
+		{
+		EC_POINT **p;
+
+		for (p = points; *p != NULL; p++)
+			EC_POINT_free(*p);
+		OPENSSL_free(points);
+		}
+	if (tmp_point)
+		EC_POINT_free(tmp_point);
+	if (base)
+		EC_POINT_free(base);
+	return ret;
+	}
+
+
+int ec_wNAF_have_precompute_mult(const EC_GROUP *group)
+	{
+	if (EC_EX_DATA_get_data(group->extra_data, ec_pre_comp_dup, ec_pre_comp_free, ec_pre_comp_clear_free) != NULL)
+		return 1;
+	else
+		return 0;
+	}