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I want to extract coefficient $A$ and $B$ from Curve25519 represented in Montgomery form as $B v^2 = u^3 + A u^2 + u$.

What are the $A$ and $B$ coefficients of Curve25519 in Montgomery form?

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The equation for a Montgomery curve is:

$B y^2 = x^3 +A x^2 + x$

The Curve25519 paper states the Curve25519 equation on page 2:

$y^2 = x^3 + 486662x^2 + x \pmod {2^{255}-19}$

Thus

$A=486662$ and $B = 1$.

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