net.i2p.crypto.eddsa.math

Interface ScalarOps

All Known Implementing Classes:

BigIntegerScalarOps, Ed25519ScalarOps

public interface ScalarOps

Method Summary

Modifier and Type	Method and Description
byte[]	multiplyAndAdd(byte[] a, byte[] b, byte[] c) $r = (a * b + c) \bmod l$
byte[]	reduce(byte[] s) Reduce the given scalar mod $l$.

Method Detail

reduce

byte[] reduce(byte[] s)

Reduce the given scalar mod $l$.

From the Ed25519 paper:
Here we interpret $2b$-bit strings in little-endian form as integers in $\{0, 1,..., 2^{(2b)}-1\}$.

Parameters:

s - the scalar to reduce

Returns:

$s \bmod l$

multiplyAndAdd

byte[] multiplyAndAdd(byte[] a,
                      byte[] b,
                      byte[] c)

$r = (a * b + c) \bmod l$

Parameters:

a - a scalar

b - a scalar

c - a scalar

Returns:

$(a*b + c) \bmod l$