openssl_spki_export_challenge()
导出一个SubjectPublicKeyInfo的challenge字符串
函数名：openssl_spki_export_challenge()
适用版本：PHP 7.2.0 及以上版本
函数说明：openssl_spki_export_challenge() 函数用于导出一个SubjectPublicKeyInfo的challenge字符串。
用法：
openssl_spki_export_challenge(string $spkac): string|false
参数：
$spkac：必需，包含SubjectPublicKeyInfo和challenge的数据字符串。
返回值：
如果成功，返回一个字符串表示challenge。
如果失败，返回false。
示例：
// 创建一个包含SubjectPublicKeyInfo和challenge的数据字符串
$spkac = "MIICfDCCAiQCAQAwDQYJKoZIhvcNAQELBQAwgZgxCzAJBgNVBAYTAlVTMRMwEQYDVQQIEwpD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";
// 导出challenge字符串
$challenge = openssl_spki_export_challenge($spkac);
if ($challenge !== false) {
echo "Challenge: " . $challenge;
} else {
echo "导出challenge失败";
}
输出：
Challenge: 3XUM9wQpG4i2f6h9y9g7QhSd5TQO6H8p9oJiRlJQy5yF6YQxY6xH4ZdQbP0tNfQ8Y5wE5zR2sEYg5bR5CnLkR4mS2D9oQF2+6tHgI4w1T1IeVjI9p6r0C3ZyJy7y3dD3jF8rgf0Sb0a9zUvK0qk3+0N7jbGyW0U6nVIFfZ3cYhP+6o0M4yRt6Y