import OpenSSL-1.0.0a

1 files changed, 17 insertions, 16 deletions

diff --git a/src/lib/libcrypto/ec/ec2_mult.c b/src/lib/libcrypto/ec/ec2_mult.c
index ff368fd7d7..ab631a50a2 100644
--- a/src/lib/libcrypto/ec/ec2_mult.c
+++ b/src/lib/libcrypto/ec/ec2_mult.c
@@ -76,7 +76,7 @@
  * coordinates.
  * Uses algorithm Mdouble in appendix of 
  *     Lopez, J. and Dahab, R.  "Fast multiplication on elliptic curves over 
- *     GF(2^m) without precomputation".
+ *     GF(2^m) without precomputation" (CHES '99, LNCS 1717).
  * modified to not require precomputation of c=b^{2^{m-1}}.
  */
 static int gf2m_Mdouble(const EC_GROUP *group, BIGNUM *x, BIGNUM *z, BN_CTX *ctx)
@@ -107,8 +107,8 @@ static int gf2m_Mdouble(const EC_GROUP *group, BIGNUM *x, BIGNUM *z, BN_CTX *ctx
 /* Compute the x-coordinate x1/z1 for the point (x1/z1)+(x2/x2) in Montgomery 
  * projective coordinates.
  * Uses algorithm Madd in appendix of 
- *     Lopex, J. and Dahab, R.  "Fast multiplication on elliptic curves over 
- *     GF(2^m) without precomputation".
+ *     Lopez, J. and Dahab, R.  "Fast multiplication on elliptic curves over 
+ *     GF(2^m) without precomputation" (CHES '99, LNCS 1717).
  */
 static int gf2m_Madd(const EC_GROUP *group, const BIGNUM *x, BIGNUM *x1, BIGNUM *z1, 
         const BIGNUM *x2, const BIGNUM *z2, BN_CTX *ctx)
@@ -140,8 +140,8 @@ static int gf2m_Madd(const EC_GROUP *group, const BIGNUM *x, BIGNUM *x1, BIGNUM
 
 /* Compute the x, y affine coordinates from the point (x1, z1) (x2, z2) 
  * using Montgomery point multiplication algorithm Mxy() in appendix of 
- *     Lopex, J. and Dahab, R.  "Fast multiplication on elliptic curves over 
- *     GF(2^m) without precomputation".
+ *     Lopez, J. and Dahab, R.  "Fast multiplication on elliptic curves over 
+ *     GF(2^m) without precomputation" (CHES '99, LNCS 1717).
  * Returns:
  *     0 on error
  *     1 if return value should be the point at infinity
@@ -209,15 +209,15 @@ static int gf2m_Mxy(const EC_GROUP *group, const BIGNUM *x, const BIGNUM *y, BIG
 /* Computes scalar*point and stores the result in r.
  * point can not equal r.
  * Uses algorithm 2P of
- *     Lopex, J. and Dahab, R.  "Fast multiplication on elliptic curves over 
- *     GF(2^m) without precomputation".
+ *     Lopez, J. and Dahab, R.  "Fast multiplication on elliptic curves over 
+ *     GF(2^m) without precomputation" (CHES '99, LNCS 1717).
  */
 static int ec_GF2m_montgomery_point_multiply(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
         const EC_POINT *point, BN_CTX *ctx)
         {
         BIGNUM *x1, *x2, *z1, *z2;
-        int ret = 0, i, j;
-        BN_ULONG mask;
+        int ret = 0, i;
+        BN_ULONG mask,word;
 
         if (r == point)
                 {
@@ -251,22 +251,24 @@ static int ec_GF2m_montgomery_point_multiply(const EC_GROUP *group, EC_POINT *r,
         if (!BN_GF2m_add(x2, x2, &group->b)) goto err; /* x2 = x^4 + b */
 
         /* find top most bit and go one past it */
-        i = scalar->top - 1; j = BN_BITS2 - 1;
+        i = scalar->top - 1;
         mask = BN_TBIT;
-        while (!(scalar->d[i] & mask)) { mask >>= 1; j--; }
-        mask >>= 1; j--;
+        word = scalar->d[i];
+        while (!(word & mask)) mask >>= 1;
+        mask >>= 1;
         /* if top most bit was at word break, go to next word */
         if (!mask) 
                 {
-                i--; j = BN_BITS2 - 1;
+                i--;
                 mask = BN_TBIT;
                 }
 
         for (; i >= 0; i--)
                 {
-                for (; j >= 0; j--)
+                word = scalar->d[i];
+                while (mask)
                         {
-                        if (scalar->d[i] & mask)
+                        if (word & mask)
                                 {
                                 if (!gf2m_Madd(group, &point->X, x1, z1, x2, z2, ctx)) goto err;
                                 if (!gf2m_Mdouble(group, x2, z2, ctx)) goto err;
@@ -278,7 +280,6 @@ static int ec_GF2m_montgomery_point_multiply(const EC_GROUP *group, EC_POINT *r,
                                 }
                         mask >>= 1;
                         }
-                j = BN_BITS2 - 1;
                 mask = BN_TBIT;
                 }