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, 654 insertions, 0 deletions

diff --git a/app/openssl/crypto/bn/bn_gcd.c b/app/openssl/crypto/bn/bn_gcd.c
new file mode 100644
index 00000000..4a352119
--- /dev/null
+++ b/app/openssl/crypto/bn/bn_gcd.c
@@ -0,0 +1,654 @@
+/* crypto/bn/bn_gcd.c */
+/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
+ * All rights reserved.
+ *
+ * This package is an SSL implementation written
+ * by Eric Young (eay@cryptsoft.com).
+ * The implementation was written so as to conform with Netscapes SSL.
+ * 
+ * This library is free for commercial and non-commercial use as long as
+ * the following conditions are aheared to.  The following conditions
+ * apply to all code found in this distribution, be it the RC4, RSA,
+ * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
+ * included with this distribution is covered by the same copyright terms
+ * except that the holder is Tim Hudson (tjh@cryptsoft.com).
+ * 
+ * Copyright remains Eric Young's, and as such any Copyright notices in
+ * the code are not to be removed.
+ * If this package is used in a product, Eric Young should be given attribution
+ * as the author of the parts of the library used.
+ * This can be in the form of a textual message at program startup or
+ * in documentation (online or textual) provided with the package.
+ * 
+ * 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 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 acknowledgement:
+ *    "This product includes cryptographic software written by
+ *     Eric Young (eay@cryptsoft.com)"
+ *    The word 'cryptographic' can be left out if the rouines from the library
+ *    being used are not cryptographic related :-).
+ * 4. If you include any Windows specific code (or a derivative thereof) from 
+ *    the apps directory (application code) you must include an acknowledgement:
+ *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
+ * 
+ * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
+ * ANY EXPRESS 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 AUTHOR OR 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.
+ * 
+ * The licence and distribution terms for any publically available version or
+ * derivative of this code cannot be changed.  i.e. this code cannot simply be
+ * copied and put under another distribution licence
+ * [including the GNU Public Licence.]
+ */
+/* ====================================================================
+ * Copyright (c) 1998-2001 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).
+ *
+ */
+
+#include "cryptlib.h"
+#include "bn_lcl.h"
+
+static BIGNUM *euclid(BIGNUM *a, BIGNUM *b);
+
+int BN_gcd(BIGNUM *r, const BIGNUM *in_a, const BIGNUM *in_b, BN_CTX *ctx)
+	{
+	BIGNUM *a,*b,*t;
+	int ret=0;
+
+	bn_check_top(in_a);
+	bn_check_top(in_b);
+
+	BN_CTX_start(ctx);
+	a = BN_CTX_get(ctx);
+	b = BN_CTX_get(ctx);
+	if (a == NULL || b == NULL) goto err;
+
+	if (BN_copy(a,in_a) == NULL) goto err;
+	if (BN_copy(b,in_b) == NULL) goto err;
+	a->neg = 0;
+	b->neg = 0;
+
+	if (BN_cmp(a,b) < 0) { t=a; a=b; b=t; }
+	t=euclid(a,b);
+	if (t == NULL) goto err;
+
+	if (BN_copy(r,t) == NULL) goto err;
+	ret=1;
+err:
+	BN_CTX_end(ctx);
+	bn_check_top(r);
+	return(ret);
+	}
+
+static BIGNUM *euclid(BIGNUM *a, BIGNUM *b)
+	{
+	BIGNUM *t;
+	int shifts=0;
+
+	bn_check_top(a);
+	bn_check_top(b);
+
+	/* 0 <= b <= a */
+	while (!BN_is_zero(b))
+		{
+		/* 0 < b <= a */
+
+		if (BN_is_odd(a))
+			{
+			if (BN_is_odd(b))
+				{
+				if (!BN_sub(a,a,b)) goto err;
+				if (!BN_rshift1(a,a)) goto err;
+				if (BN_cmp(a,b) < 0)
+					{ t=a; a=b; b=t; }
+				}
+			else		/* a odd - b even */
+				{
+				if (!BN_rshift1(b,b)) goto err;
+				if (BN_cmp(a,b) < 0)
+					{ t=a; a=b; b=t; }
+				}
+			}
+		else			/* a is even */
+			{
+			if (BN_is_odd(b))
+				{
+				if (!BN_rshift1(a,a)) goto err;
+				if (BN_cmp(a,b) < 0)
+					{ t=a; a=b; b=t; }
+				}
+			else		/* a even - b even */
+				{
+				if (!BN_rshift1(a,a)) goto err;
+				if (!BN_rshift1(b,b)) goto err;
+				shifts++;
+				}
+			}
+		/* 0 <= b <= a */
+		}
+
+	if (shifts)
+		{
+		if (!BN_lshift(a,a,shifts)) goto err;
+		}
+	bn_check_top(a);
+	return(a);
+err:
+	return(NULL);
+	}
+
+
+/* solves ax == 1 (mod n) */
+static BIGNUM *BN_mod_inverse_no_branch(BIGNUM *in,
+        const BIGNUM *a, const BIGNUM *n, BN_CTX *ctx);
+BIGNUM *BN_mod_inverse(BIGNUM *in,
+	const BIGNUM *a, const BIGNUM *n, BN_CTX *ctx)
+	{
+	BIGNUM *A,*B,*X,*Y,*M,*D,*T,*R=NULL;
+	BIGNUM *ret=NULL;
+	int sign;
+
+	if ((BN_get_flags(a, BN_FLG_CONSTTIME) != 0) || (BN_get_flags(n, BN_FLG_CONSTTIME) != 0))
+		{
+		return BN_mod_inverse_no_branch(in, a, n, ctx);
+		}
+
+	bn_check_top(a);
+	bn_check_top(n);
+
+	BN_CTX_start(ctx);
+	A = BN_CTX_get(ctx);
+	B = BN_CTX_get(ctx);
+	X = BN_CTX_get(ctx);
+	D = BN_CTX_get(ctx);
+	M = BN_CTX_get(ctx);
+	Y = BN_CTX_get(ctx);
+	T = BN_CTX_get(ctx);
+	if (T == NULL) goto err;
+
+	if (in == NULL)
+		R=BN_new();
+	else
+		R=in;
+	if (R == NULL) goto err;
+
+	BN_one(X);
+	BN_zero(Y);
+	if (BN_copy(B,a) == NULL) goto err;
+	if (BN_copy(A,n) == NULL) goto err;
+	A->neg = 0;
+	if (B->neg || (BN_ucmp(B, A) >= 0))
+		{
+		if (!BN_nnmod(B, B, A, ctx)) goto err;
+		}
+	sign = -1;
+	/* From  B = a mod |n|,  A = |n|  it follows that
+	 *
+	 *      0 <= B < A,
+	 *     -sign*X*a  ==  B   (mod |n|),
+	 *      sign*Y*a  ==  A   (mod |n|).
+	 */
+
+	if (BN_is_odd(n) && (BN_num_bits(n) <= (BN_BITS <= 32 ? 450 : 2048)))
+		{
+		/* Binary inversion algorithm; requires odd modulus.
+		 * This is faster than the general algorithm if the modulus
+		 * is sufficiently small (about 400 .. 500 bits on 32-bit
+		 * sytems, but much more on 64-bit systems) */
+		int shift;
+		
+		while (!BN_is_zero(B))
+			{
+			/*
+			 *      0 < B < |n|,
+			 *      0 < A <= |n|,
+			 * (1) -sign*X*a  ==  B   (mod |n|),
+			 * (2)  sign*Y*a  ==  A   (mod |n|)
+			 */
+
+			/* Now divide  B  by the maximum possible power of two in the integers,
+			 * and divide  X  by the same value mod |n|.
+			 * When we're done, (1) still holds. */
+			shift = 0;
+			while (!BN_is_bit_set(B, shift)) /* note that 0 < B */
+				{
+				shift++;
+				
+				if (BN_is_odd(X))
+					{
+					if (!BN_uadd(X, X, n)) goto err;
+					}
+				/* now X is even, so we can easily divide it by two */
+				if (!BN_rshift1(X, X)) goto err;
+				}
+			if (shift > 0)
+				{
+				if (!BN_rshift(B, B, shift)) goto err;
+				}
+
+
+			/* Same for  A  and  Y.  Afterwards, (2) still holds. */
+			shift = 0;
+			while (!BN_is_bit_set(A, shift)) /* note that 0 < A */
+				{
+				shift++;
+				
+				if (BN_is_odd(Y))
+					{
+					if (!BN_uadd(Y, Y, n)) goto err;
+					}
+				/* now Y is even */
+				if (!BN_rshift1(Y, Y)) goto err;
+				}
+			if (shift > 0)
+				{
+				if (!BN_rshift(A, A, shift)) goto err;
+				}
+
+			
+			/* We still have (1) and (2).
+			 * Both  A  and  B  are odd.
+			 * The following computations ensure that
+			 *
+			 *     0 <= B < |n|,
+			 *      0 < A < |n|,
+			 * (1) -sign*X*a  ==  B   (mod |n|),
+			 * (2)  sign*Y*a  ==  A   (mod |n|),
+			 *
+			 * and that either  A  or  B  is even in the next iteration.
+			 */
+			if (BN_ucmp(B, A) >= 0)
+				{
+				/* -sign*(X + Y)*a == B - A  (mod |n|) */
+				if (!BN_uadd(X, X, Y)) goto err;
+				/* NB: we could use BN_mod_add_quick(X, X, Y, n), but that
+				 * actually makes the algorithm slower */
+				if (!BN_usub(B, B, A)) goto err;
+				}
+			else
+				{
+				/*  sign*(X + Y)*a == A - B  (mod |n|) */
+				if (!BN_uadd(Y, Y, X)) goto err;
+				/* as above, BN_mod_add_quick(Y, Y, X, n) would slow things down */
+				if (!BN_usub(A, A, B)) goto err;
+				}
+			}
+		}
+	else
+		{
+		/* general inversion algorithm */
+
+		while (!BN_is_zero(B))
+			{
+			BIGNUM *tmp;
+			
+			/*
+			 *      0 < B < A,
+			 * (*) -sign*X*a  ==  B   (mod |n|),
+			 *      sign*Y*a  ==  A   (mod |n|)
+			 */
+			
+			/* (D, M) := (A/B, A%B) ... */
+			if (BN_num_bits(A) == BN_num_bits(B))
+				{
+				if (!BN_one(D)) goto err;
+				if (!BN_sub(M,A,B)) goto err;
+				}
+			else if (BN_num_bits(A) == BN_num_bits(B) + 1)
+				{
+				/* A/B is 1, 2, or 3 */
+				if (!BN_lshift1(T,B)) goto err;
+				if (BN_ucmp(A,T) < 0)
+					{
+					/* A < 2*B, so D=1 */
+					if (!BN_one(D)) goto err;
+					if (!BN_sub(M,A,B)) goto err;
+					}
+				else
+					{
+					/* A >= 2*B, so D=2 or D=3 */
+					if (!BN_sub(M,A,T)) goto err;
+					if (!BN_add(D,T,B)) goto err; /* use D (:= 3*B) as temp */
+					if (BN_ucmp(A,D) < 0)
+						{
+						/* A < 3*B, so D=2 */
+						if (!BN_set_word(D,2)) goto err;
+						/* M (= A - 2*B) already has the correct value */
+						}
+					else
+						{
+						/* only D=3 remains */
+						if (!BN_set_word(D,3)) goto err;
+						/* currently  M = A - 2*B,  but we need  M = A - 3*B */
+						if (!BN_sub(M,M,B)) goto err;
+						}
+					}
+				}
+			else
+				{
+				if (!BN_div(D,M,A,B,ctx)) goto err;
+				}
+			
+			/* Now
+			 *      A = D*B + M;
+			 * thus we have
+			 * (**)  sign*Y*a  ==  D*B + M   (mod |n|).
+			 */
+			
+			tmp=A; /* keep the BIGNUM object, the value does not matter */
+			
+			/* (A, B) := (B, A mod B) ... */
+			A=B;
+			B=M;
+			/* ... so we have  0 <= B < A  again */
+			
+			/* Since the former  M  is now  B  and the former  B  is now  A,
+			 * (**) translates into
+			 *       sign*Y*a  ==  D*A + B    (mod |n|),
+			 * i.e.
+			 *       sign*Y*a - D*A  ==  B    (mod |n|).
+			 * Similarly, (*) translates into
+			 *      -sign*X*a  ==  A          (mod |n|).
+			 *
+			 * Thus,
+			 *   sign*Y*a + D*sign*X*a  ==  B  (mod |n|),
+			 * i.e.
+			 *        sign*(Y + D*X)*a  ==  B  (mod |n|).
+			 *
+			 * So if we set  (X, Y, sign) := (Y + D*X, X, -sign),  we arrive back at
+			 *      -sign*X*a  ==  B   (mod |n|),
+			 *       sign*Y*a  ==  A   (mod |n|).
+			 * Note that  X  and  Y  stay non-negative all the time.
+			 */
+			
+			/* most of the time D is very small, so we can optimize tmp := D*X+Y */
+			if (BN_is_one(D))
+				{
+				if (!BN_add(tmp,X,Y)) goto err;
+				}
+			else
+				{
+				if (BN_is_word(D,2))
+					{
+					if (!BN_lshift1(tmp,X)) goto err;
+					}
+				else if (BN_is_word(D,4))
+					{
+					if (!BN_lshift(tmp,X,2)) goto err;
+					}
+				else if (D->top == 1)
+					{
+					if (!BN_copy(tmp,X)) goto err;
+					if (!BN_mul_word(tmp,D->d[0])) goto err;
+					}
+				else
+					{
+					if (!BN_mul(tmp,D,X,ctx)) goto err;
+					}
+				if (!BN_add(tmp,tmp,Y)) goto err;
+				}
+			
+			M=Y; /* keep the BIGNUM object, the value does not matter */
+			Y=X;
+			X=tmp;
+			sign = -sign;
+			}
+		}
+		
+	/*
+	 * The while loop (Euclid's algorithm) ends when
+	 *      A == gcd(a,n);
+	 * we have
+	 *       sign*Y*a  ==  A  (mod |n|),
+	 * where  Y  is non-negative.
+	 */
+
+	if (sign < 0)
+		{
+		if (!BN_sub(Y,n,Y)) goto err;
+		}
+	/* Now  Y*a  ==  A  (mod |n|).  */
+	
+
+	if (BN_is_one(A))
+		{
+		/* Y*a == 1  (mod |n|) */
+		if (!Y->neg && BN_ucmp(Y,n) < 0)
+			{
+			if (!BN_copy(R,Y)) goto err;
+			}
+		else
+			{
+			if (!BN_nnmod(R,Y,n,ctx)) goto err;
+			}
+		}
+	else
+		{
+		BNerr(BN_F_BN_MOD_INVERSE,BN_R_NO_INVERSE);
+		goto err;
+		}
+	ret=R;
+err:
+	if ((ret == NULL) && (in == NULL)) BN_free(R);
+	BN_CTX_end(ctx);
+	bn_check_top(ret);
+	return(ret);
+	}
+
+
+/* BN_mod_inverse_no_branch is a special version of BN_mod_inverse. 
+ * It does not contain branches that may leak sensitive information.
+ */
+static BIGNUM *BN_mod_inverse_no_branch(BIGNUM *in,
+	const BIGNUM *a, const BIGNUM *n, BN_CTX *ctx)
+	{
+	BIGNUM *A,*B,*X,*Y,*M,*D,*T,*R=NULL;
+	BIGNUM local_A, local_B;
+	BIGNUM *pA, *pB;
+	BIGNUM *ret=NULL;
+	int sign;
+
+	bn_check_top(a);
+	bn_check_top(n);
+
+	BN_CTX_start(ctx);
+	A = BN_CTX_get(ctx);
+	B = BN_CTX_get(ctx);
+	X = BN_CTX_get(ctx);
+	D = BN_CTX_get(ctx);
+	M = BN_CTX_get(ctx);
+	Y = BN_CTX_get(ctx);
+	T = BN_CTX_get(ctx);
+	if (T == NULL) goto err;
+
+	if (in == NULL)
+		R=BN_new();
+	else
+		R=in;
+	if (R == NULL) goto err;
+
+	BN_one(X);
+	BN_zero(Y);
+	if (BN_copy(B,a) == NULL) goto err;
+	if (BN_copy(A,n) == NULL) goto err;
+	A->neg = 0;
+
+	if (B->neg || (BN_ucmp(B, A) >= 0))
+		{
+		/* Turn BN_FLG_CONSTTIME flag on, so that when BN_div is invoked,
+	 	 * BN_div_no_branch will be called eventually.
+	 	 */
+		pB = &local_B;
+		BN_with_flags(pB, B, BN_FLG_CONSTTIME);	
+		if (!BN_nnmod(B, pB, A, ctx)) goto err;
+		}
+	sign = -1;
+	/* From  B = a mod |n|,  A = |n|  it follows that
+	 *
+	 *      0 <= B < A,
+	 *     -sign*X*a  ==  B   (mod |n|),
+	 *      sign*Y*a  ==  A   (mod |n|).
+	 */
+
+	while (!BN_is_zero(B))
+		{
+		BIGNUM *tmp;
+		
+		/*
+		 *      0 < B < A,
+		 * (*) -sign*X*a  ==  B   (mod |n|),
+		 *      sign*Y*a  ==  A   (mod |n|)
+		 */
+
+		/* Turn BN_FLG_CONSTTIME flag on, so that when BN_div is invoked,
+	 	 * BN_div_no_branch will be called eventually.
+	 	 */
+		pA = &local_A;
+		BN_with_flags(pA, A, BN_FLG_CONSTTIME);	
+		
+		/* (D, M) := (A/B, A%B) ... */		
+		if (!BN_div(D,M,pA,B,ctx)) goto err;
+		
+		/* Now
+		 *      A = D*B + M;
+		 * thus we have
+		 * (**)  sign*Y*a  ==  D*B + M   (mod |n|).
+		 */
+		
+		tmp=A; /* keep the BIGNUM object, the value does not matter */
+		
+		/* (A, B) := (B, A mod B) ... */
+		A=B;
+		B=M;
+		/* ... so we have  0 <= B < A  again */
+		
+		/* Since the former  M  is now  B  and the former  B  is now  A,
+		 * (**) translates into
+		 *       sign*Y*a  ==  D*A + B    (mod |n|),
+		 * i.e.
+		 *       sign*Y*a - D*A  ==  B    (mod |n|).
+		 * Similarly, (*) translates into
+		 *      -sign*X*a  ==  A          (mod |n|).
+		 *
+		 * Thus,
+		 *   sign*Y*a + D*sign*X*a  ==  B  (mod |n|),
+		 * i.e.
+		 *        sign*(Y + D*X)*a  ==  B  (mod |n|).
+		 *
+		 * So if we set  (X, Y, sign) := (Y + D*X, X, -sign),  we arrive back at
+		 *      -sign*X*a  ==  B   (mod |n|),
+		 *       sign*Y*a  ==  A   (mod |n|).
+		 * Note that  X  and  Y  stay non-negative all the time.
+		 */
+			
+		if (!BN_mul(tmp,D,X,ctx)) goto err;
+		if (!BN_add(tmp,tmp,Y)) goto err;
+
+		M=Y; /* keep the BIGNUM object, the value does not matter */
+		Y=X;
+		X=tmp;
+		sign = -sign;
+		}
+		
+	/*
+	 * The while loop (Euclid's algorithm) ends when
+	 *      A == gcd(a,n);
+	 * we have
+	 *       sign*Y*a  ==  A  (mod |n|),
+	 * where  Y  is non-negative.
+	 */
+
+	if (sign < 0)
+		{
+		if (!BN_sub(Y,n,Y)) goto err;
+		}
+	/* Now  Y*a  ==  A  (mod |n|).  */
+
+	if (BN_is_one(A))
+		{
+		/* Y*a == 1  (mod |n|) */
+		if (!Y->neg && BN_ucmp(Y,n) < 0)
+			{
+			if (!BN_copy(R,Y)) goto err;
+			}
+		else
+			{
+			if (!BN_nnmod(R,Y,n,ctx)) goto err;
+			}
+		}
+	else
+		{
+		BNerr(BN_F_BN_MOD_INVERSE_NO_BRANCH,BN_R_NO_INVERSE);
+		goto err;
+		}
+	ret=R;
+err:
+	if ((ret == NULL) && (in == NULL)) BN_free(R);
+	BN_CTX_end(ctx);
+	bn_check_top(ret);
+	return(ret);
+	}