目前没有办法用jspdf设置密码。使用node-qpdf软件包来保护您的PDF。

var qpdf = require('node-qpdf');

var options = {
    keyLength: 128,
    password: 'YOUR_PASSWORD_TO_ENCRYPT'
}

qpdf.encrypt(localFilePath, options);

在最新发布的jspdf >= 2.2.0中，他们增加了加密机制，以密码保护pdf文件。但注意
jsPDF supports encryption of PDF just uses RC4 40-bit which is kown to be weak and is NOT state of the art.
使用的例子是：

var doc = new jsPDF({
  encryption: {
    userPassword: "user",
    ownerPassword: "owner",
    userPermissions: ["print", "modify", "copy", "annot-forms"]
  }
});