OBSERVATION CHAMBER / ACTIVE

Elliptic Curve Group Law

Place two points on an elliptic curve, trace the chord or tangent, and compare exact addition over rational presets and small finite fields.

geometry Operational
02

WATCH THE LAW

Curve and construction

Click the real curve to place the selected point.

continuous curve
PQR = P + Qthird intersection
03

READ THE RESULT

Group-law result

NOT COMPUTED P + Q = —

Choose two points and trace their sum.

operation
slope
curve
smooth
order of P

Elliptic Curve Group Law report

SYSTEM NOTE

For E: y²=x³+ax+b with 4a³+27b²≠0, use λ=(yQ−yP)/(xQ−xP) for a chord or λ=(3xP²+a)/(2yP) for a tangent. Then xR=λ²−xP−xQ and yR=λ(xP−xR)−yP. The identity is O, P+O=P, and P+(−P)=O. Over Fp, division means multiplication by a modular inverse.

OBSERVATION POLICY

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