# sodium_crypto_core_ristretto255_is_valid_point

(PHP 8 >= 8.1.0)

sodium_crypto_core_ristretto255_is_valid_point — Determines if a point on the ristretto255 curve

### 说明

sodium_crypto_core_ristretto255_is_valid_point(string `$s`): bool

Determines if a point on the ristretto255 curve, in canonical form, on the main subgroup, and that the point doesn't have a small order. Available as of libsodium 1.0.18.

警告

本函数还未编写文档，仅有参数列表。

### 参数

`s`

  An Elliptic-curve point.

### 返回值

Returns `true` if `s` is on the ristretto255 curve, `false` otherwise.

### 示例

示例 #1 sodium_crypto_core_ristretto255_is_valid_point() example

`<?php
$foo = sodium_crypto_core_ristretto255_scalar_random();
$bar = sodium_crypto_scalarmult_ristretto255_base($foo);
var_dump(sodium_crypto_core_ristretto255_is_valid_point($bar));
?>`

以上示例会输出：

    bool(true)

### 参见

- sodium_crypto_core_ristretto255_scalar_random() - Generates a random key
- sodium_crypto_scalarmult_ristretto255_base() - Calculates the public key from a secret key

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