more rigorous tests. elligator still fails. problem: extracting xy is quite technical

include/decaf_255.hxx

@@ -107,6 +107,18 @@ public:
             throw LengthException();
         return Block(data()+off, length);
     }
+    
+    /* Content-wise comparison; constant-time if they are the same length.
+     * FIXME: is it wise to have a content-wise compare on objects that may be mutable?
+     */ 
+    inline decaf_bool_t operator==(const Block &b) const NOEXCEPT {
+        return ~(*this != b);
+    }
+    
+    inline decaf_bool_t operator!=(const Block &b) const NOEXCEPT {
+        if (b.size() != size()) return true;
+        return ~decaf_memeq(b,*this,size());
+    }
 
     /** Virtual destructor for SecureBlock. TODO: probably means vtable?  Make bool? */
     inline virtual ~Block() {};

test/test_decaf.cxx

@@ -215,6 +215,13 @@ static void test_ec() {
         Point r = Point::from_hash(buffer);
         
         point_check(test,p,q,r,0,0,p,Point((decaf::SecureBuffer)p),"round-trip");
+        Point pp = p;
+        (pp).debugging_torque_in_place();
+        if (decaf::SecureBuffer(pp) != decaf::SecureBuffer(p)) {
+            test.fail();
+            printf("Fail torque seq test\n");
+        }
+        point_check(test,p,q,r,0,0,p,pp,"torque eq");
         point_check(test,p,q,r,0,0,p+q,q+p,"commute add");
         point_check(test,p,q,r,0,0,(p-q)+q,p,"correct sub");
         point_check(test,p,q,r,0,0,p+(q+r),(p+q)+r,"assoc add");