signature模块rsa安卓解密失败

helpinfo

var signStr = "";
    var sign = api.require("signature");
    var publicKey = 'MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA2Sz4vd+qG4fK7gGHIYkokzDDpggq/7i4jz+eZ/JVQfMB24MJEzVM9cT5mohM+IqpUtHnDm11mTertxAhf/ioTZW+8NB9wlO9h6FCnO/L49GrYz1eikTyqGkG4csOjoX9YLIL5ElSycsrnlwnW9p/OpFaCfY84bNRp713VJvJONS8BJMjZVwyNmUU63DquhGjpFG+AZXN3a7UD5lBgVokIpxcTy0mcjaUQgQuX6aRhfJ2QC+7VKNH56yPZli4nQxUkehAC2aficyHasuXpTLsZ/UMSLUumEOCt+0+DxfxAkApKkVfSs+8ZW6fttzpVA4BubmwxJzgqqB+3hOeAs8+BwIDAQAB';
    // var publicKey = fileRead('widget://res/public_key.key');
    if (api.systemType == 'ios'){
      publicKey = 'widget://res/public_key.der';
    }
    signStr = sign.rsaSync({
        data: 'APICloud',
        publicKey: publicKey
    });
    return signStr;

源码就这么几行。
ios得到的加密字符串中后台能解开
但是，安卓生成的加密字符串后台解不开。