Roulette (curve) in this case, the point lies on the circle then the roulette is a cycloid. A related concept is a glissette, the curve described by a point attached to a given curve as it slides along two (or more) given curves. Formally speaking, the curves must be differentiable curves in the Euclidean plane. The "fixed curve" is kept invariant; the "rolling curve" is subjected to a continuous congruence transformation such that at all times the curves are tangent at a point of contact that moves with the same speed when taken along either curve (another way to express this constraint
Elliptic curve point multiplication scalar (integer) "n" and a point that lies on the curve, "E". This type of curve is known as a Weierstrass curve. The security of modern ECC depends on the intractability of determining "n" from given known values of "Q" and "P" if "n" is large (known as the "elliptic curve discrete logarithm problem"). This is because the addition of two points on an elliptic curve (or the addition of one point to itself) yields a third point on the elliptic curve whose location has no immediately obvious relationship to the locations of the first two, and repeating this many