Corrections to the comments in BN_mod_inverse.

diff --git a/crypto/bn/bn_gcd.c b/crypto/bn/bn_gcd.c
index a61ba5ee11a22723b44d7434a1fb8bcd2b790692..d5caf5136f1248007dc6bb6f215665351cc055a9 100644 (file)
--- a/crypto/bn/bn_gcd.c
+++ b/crypto/bn/bn_gcd.c
@@ -240,7 +240,7 @@ BIGNUM *BN_mod_inverse(BIGNUM *in,
        /* From  B = a mod |n|,  A = |n|  it follows that
         *
         *      0 <= B < A,
        /* From  B = a mod |n|,  A = |n|  it follows that
         *
         *      0 <= B < A,

-        *           X*a  ==  B   (mod |n|),
+        *      sign*X*a  ==  B   (mod |n|),

         *     -sign*Y*a  ==  A   (mod |n|).
         */
 
         *     -sign*Y*a  ==  A   (mod |n|).
         */
 


@@ -250,7 +250,7 @@ BIGNUM *BN_mod_inverse(BIGNUM *in,
 
                /*
                 *      0 < B < A,
 
                /*
                 *      0 < B < A,

-                * (*)       X*a  ==  B   (mod |n|),
+                * (*)  sign*X*a  ==  B   (mod |n|),

                 *     -sign*Y*a  ==  A   (mod |n|)
                 */
 
                 *     -sign*Y*a  ==  A   (mod |n|)
                 */
 


@@ -314,15 +314,15 @@ BIGNUM *BN_mod_inverse(BIGNUM *in,
                 * i.e.
                 *      -sign*Y*a - D*A  ==  B    (mod |n|).
                 * Similarly, (*) translates into
                 * i.e.
                 *      -sign*Y*a - D*A  ==  B    (mod |n|).
                 * Similarly, (*) translates into

-                *      X*a  ==  A          (mod |n|).
+                *       sign*X*a  ==  A          (mod |n|).

                 *
                 * Thus,
                 *
                 * Thus,

-                *      -sign*Y*a - D*X*a  ==  B  (mod |n|),
+                *  -sign*Y*a - D*sign*X*a  ==  B  (mod |n|),

                 * i.e.
                 * i.e.

-                *      -sign*(Y + D*X)*a  ==  B  (mod |n|).
+                *       -sign*(Y + D*X)*a  ==  B  (mod |n|).

                 *
                 * So if we set  (X, Y, sign) := (Y + D*X, X, -sign),  we arrive back at
                 *
                 * So if we set  (X, Y, sign) := (Y + D*X, X, -sign),  we arrive back at

-                *            X*a  ==  B   (mod |n|),
+                *       sign*X*a  ==  B   (mod |n|),

                 *      -sign*Y*a  ==  A   (mod |n|).
                 * Note that  X  and  Y  stay non-negative all the time.
                 */
                 *      -sign*Y*a  ==  A   (mod |n|).
                 * Note that  X  and  Y  stay non-negative all the time.
                 */


@@ -361,7 +361,7 @@ BIGNUM *BN_mod_inverse(BIGNUM *in,
                }
 
        /*
                }
 
        /*

-        * The while loop ends when
+        * The while loop (Euclid's algorithm) ends when

         *      A == gcd(a,n);
         * we have
         *      -sign*Y*a  ==  A  (mod |n|),
         *      A == gcd(a,n);
         * we have
         *      -sign*Y*a  ==  A  (mod |n|),