先引入function代码

/* 公众号关注填写关键词*/
add_shortcode('gzh2v', 'baolog_secret_content');

function baolog_secret_content($atts, $content = null) {
    extract(shortcode_atts(array('key' => null, 'keyword' => null), $atts));
    if (isset($_POST['secret_key']) && $_POST['secret_key'] == $key) {
        return $content;
    } else {
        return ' < div class = "gzhhide" >
            < div class = "hidden-blur-poster"
        style = "background-image: url(https://lz.sinaimg.cn/mw690/73f6551dly1hd90iqdzpoj207m03k0dz.jpg);" > < /div> < div > < img class = "gzhcode"
        style = "vertical-align: revert"
        src = "'._lot('baolog-opt-accordion-shortcodes')['baolog-shortcodes-gzhgz-qrcode'].'"
        width = "130"
        height = "130"
        alt = "线报主题" > < /div> < div class = "gzhtitle" > 此内容为隐藏内容， 输入密码后可见！ < i class = "fa icon icon-lock" > < /i><span></span > < /div> < div class = "gzh-content" > 请打开微信扫描右边的二维码回复关键字“ < span > < b > '.$keyword.' < /b></span > ”获取密码， 也可以微信直接搜索 "<b>'._lot('baolog-opt-accordion-shortcodes')['baolog-shortcodes-gzhgz-name'].'</b>"
        关注微信公众号获取密码。 < /div> < div class = "gzhbox" > < form action = "'.get_permalink().'"
        method = "post" >
            < input id = "pwbox"
        type = "text"
        size = "20"
        name = "secret_key"
        placeholder = "请输入从公众号获取到的密码" >
            < button type = "submit" > 查看隐藏内容 < /button></form > < /div></div > ';
    }
}

其次引入CSS代码

/* 关注公众号 */
.post_hide_box,.secret-password {
    background:none repeat scroll 0 0 #efe;
    border-left:5px solid #e74c3c;
    color:#555;
    padding:10px 0 10px 10px;
    border-radius:5px;
    margin-bottom:15px;
    overflow:hidden;
    clear:both;
}
.post_hide_box .post-secret {
    font-size:18px;
    line-height:20px;
    color:#e74c3c;
    margin:5px;
}
.post_hide_box form {
    margin:15px 0;
}
.post_hide_box form span {
    font-size:18px;
    font-weight:700;
}
.post_hide_box .erweima {
    margin-left:20px;
    margin-right:16px;
}
.post_hide_box input[type=password] {
    color:#9ba1a8;
    padding:6px;
    background-color:#f6f6f6;
    border:1px solid #e4e6e8;
    font-size:12px;
    -moz-transition:border .25s linear,color .25s linear,background-color .25s linear;
    -webkit-transition:border .25s linear,color .25s linear,background-color .25s linear;
    -o-transition:border .25s linear,color .25s linear,background-color .25s linear;
    transition:border .25s linear,color .25s linear,background-color .25s linear;
}
.post_hide_box input[type=submit] {
    background:#F88C00;
    border:none;
    border:2px solid;
    border-color:#F88C00;
    border-left:none;
    border-top:none;
    padding:0px;
    width:100px;
    height:38px;
    color:#fff;
    outline:0;
    border-radius:0 0 2px 0;
    font-size:16px;
}
.post_hide_box .details span {
    color:#e74c3c;
}
.post_hide_box .details
span {
    color:#e74c3c;
}
.gzhhide .gzhcode {
    position:absolute;
    width:100px;
    height:100px;
    right:20px;
    top:50%;
    margin-top:-50px
}
.gzhhide {
    background:#fff;
    border-radius:10px;
    padding:20px;
    margin:15px 0;
    position:relative;
    /*box-shadow:0 0 20px #d0d0d0*/
}
.gzhhide .gzhtitle {
    position:relative;
    font-size:17px;
    font-weight:700;
    color:#000000cc;
    padding:6px 140px 0 40px;
    overflow:hidden;
    text-overflow:ellipsis;
    white-space:nowrap
}
.gzhhide .gzhtitle .fa {
    position:absolute;
    left:0;
    font-size:35px;
    top:0
}
.gzh-content {
    position: relative;
    padding:20px 140px 15px 0;
    font-size:14px;
    color:#000000cc;
}
.gzhbox {
    position: relative;
    padding:0 140px 10px 0;
}
.gzhbox input {
    width:45%;
    border:none;
    color:#737373;
    font-size:13px;
    height:35px;
    line-height:35px;
    background:#f2f2f2;
    border-radius:4px;
    outline:none;
    float:left;
    padding:0 10px
}
.gzhbox button {
    width:20%;
    margin-left: 2%;
    border:none;
    background:#3b8cff;
    color:#fff;
    padding:5px 0;
    font-size:14px;
    border-radius:5px
}
.gzhhide .gzhcode {
    position:absolute;
    width:100px;
    height:100px;
    right:20px;
    top:50%;
    margin-top:-50px
}
.gzhbox {
    padding:0
}
.gzh-content {
    padding:20px 90px 15px 0
}
.gzhhide .gzhcode {
    width:80px;
    height:80px
}
#vivideo {
    height:200px
}
.gzhhide .gzhtitle i {
    font-style:normal;
}

最后引入代码，插入文章使用即可

测试效果（密码123）

[gzh2v keyword=”输入关键词” key=”123″]在这里填入内容[/gzh2v]