1.都是使用openssl_sign，和openssl_verify函数，只是最后一个参数不同rsa为OPENSSL_ALGO_SHA1，rsa2为OPENSSL_ALGO_SHA256，下面是PHP本rsa签名实现类

<?php

//rsa和rsa2 PHP版签名生成以及验证类
//$content,$signature,$publicKey,$type,$content原文，$signature被验证的签名，$publicKey和$privateKey公私钥都是只有内容的一行字符串，$type为rsa，或者rsa2
class RSA{
	public static function sign($content,$privateKey,$type){
		if($type == "rsa"){
			openssl_sign($content,$signature,"-----BEGIN PRIVATE KEY-----\n".$privateKey."\n-----END PRIVATE KEY-----", OPENSSL_ALGO_SHA1);
		}elseif ($type == "rsa2") {
			openssl_sign($content,$signature,"-----BEGIN PRIVATE KEY-----\n".$privateKey."\n-----END PRIVATE KEY-----", OPENSSL_ALGO_SHA256);
		}else{
			throw new Exception("Only support OPENSSL_ALGO_SHA1 or OPENSSL_ALGO_SHA256 algorithm signature!");
		}
		return base64_encode($signature);
	}

	public static function verify($content,$signature,$publicKey,$type){
		if($type == "rsa"){
			return openssl_verify($content,base64_decode($signature),"-----BEGIN PUBLIC KEY-----\n".$publicKey."\n-----END PUBLIC KEY-----", OPENSSL_ALGO_SHA1);
		}elseif ($type == "rsa2") {
			return openssl_verify($content,base64_decode($signature),"-----BEGIN PUBLIC KEY-----\n".$publicKey."\n-----END PUBLIC KEY-----", OPENSSL_ALGO_SHA256);
		}else{
			throw new Exception("Only support OPENSSL_ALGO_SHA1 or OPENSSL_ALGO_SHA256 algorithm signature verify!");
		}
	}
}
?>