Add key import/export (close #6)

index.html

@@ -13,28 +13,57 @@ file, You can obtain one at http://mozilla.org/MPL/2.0/.
 <link rel="stylesheet" href="css/main.css" />
 
 <div class="modal fade" id="settingsModal" tabindex="-1" aria-labelledby="settingsModalLabel" aria-hidden="true">
-    <div class="modal-dialog">
+    <div class="modal-dialog modal-lg">
         <div class="modal-content">
             <div class="modal-header">
                 <h5 class="modal-title" id="settingsModalLabel">Settings</h5>
                 <button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
             </div>
             <div class="modal-body">
-                Name: <input class="form-control" type="text" id="notary_name" />
+                <div class="row">
-                Location (county/residing at): <input class="form-control" type="text" id="notary_location" />
+                    <div class="col-12 col-lg-6">
-                Commission expiration: <input class="form-control" type="text" id="notary_expires" />
+                        <h4>Notary Profile</h4>
-                Commission number: <input class="form-control" type="text" id="notary_idnumber" />
+                        Name: <input class="form-control" type="text" id="notary_name" />
-                State: <select class="form-control" id="notary_state">
+                        Location (county/residing at): <input class="form-control" type="text" id="notary_location" />
-                    <option selected></option>
+                        Commission expiration: <input class="form-control" type="text" id="notary_expires" />
-                    <option value="mt">Montana</option>
+                        Commission number: <input class="form-control" type="text" id="notary_idnumber" />
-                </select>
+                        State: <select class="form-control" id="notary_state">
-                <br>
+                            <option selected></option>
-                Stamp Preview:<br>
+                            <option value="mt">Montana</option>
-                <img src="" id="stamp-preview" />
+                        </select>
-                <br>
+                        <br>
-                Notary Signature:<br>
+                        Stamp Preview:<br>
-                <img src="" id="signature-preview" /><br>
+                        <img src="" id="stamp-preview" />
-                <div class="btn btn-primary" onclick="activateNotarySignaturePad()"><i class="fas fa-signature"></i> Draw Signature</div>
+                        <br>
+                        Notary Signature:<br>
+                        <img src="" id="signature-preview" /><br>
+                        <div class="btn btn-primary m-1" onclick="activateNotarySignaturePad()"><i class="fas fa-signature"></i> Draw Signature</div>
+                    </div>
+                    <div class="col-12 col-lg-6">
+                        <h4>Digital Signature</h4>
+                        <p>
+                            <b>MUST READ:</b> When you save a PDF with this tool, a cryptographic signature is attached.
+                            This signature can be used to prove the PDF is unchanged since notarization,
+                            and prove that you were the notary involved.
+                            <br>
+                            Signatures are generated using your private key, which you must keep secret.
+                            Someone with the private key can modify a signed PDF without detection.
+                            <b>Protect your private key like you protect your notary stamp/seal.</b>
+                            <br>
+                            A corresponding public key is also available; anyone with your public key can
+                            verify you signed a document, but cannot do anything else.
+                            It is recommended to post your public key somewhere public like a website.
+                            This way, people can ensure documents are valid. It is also recommended to
+                            <b>back up your private key</b> in case your computer malfunctions. This will ensure you don't need
+                            to make a new one. A new key won't be able to verify older signatures or vice versa.
+                        </p>
+                        <div class="btn btn-primary m-1" onclick="loadKeyFromLocalStorageWithUserFeedback()"><i class="fas fa-unlock"></i> Create/unlock private key</div>
+                        <div class="btn btn-primary m-1" onclick="exportPublicKey()"><i class="fas fa-file-export"></i> Export public key</div>
+                        <br>
+                        <div class="btn btn-danger m-1" onclick="exportPrivateKey()"><i class="fas fa-download"></i> Back up private key</div>
+                        <div class="btn btn-danger m-1" onclick="importPrivateKey()"><i class="fas fa-upload"></i> Restore private key</div>
+                    </div>
+                </div>
             </div>
             <div class="modal-footer">
                 <button type="button" class="btn btn-secondary" data-bs-dismiss="modal">Close</button>
@@ -75,7 +104,7 @@ file, You can obtain one at http://mozilla.org/MPL/2.0/.
         <a class="nav-link" href="#" onclick="addPDF()"><i class="fas fa-file-pdf"></i> Add PDF</a>
     </li>
     <li class="nav-item">
-        <a class="nav-link" href="#" onclick="savePDF()"><i class="fas fa-save"></i> Save</a>
+        <a class="nav-link" href="#" onclick="savePDF()"><i class="fas fa-save"></i> Save Signed PDF</a>
     </li>
     <li class="nav-item">
         <a class="nav-link" href="#" onclick="openSettingsModal()"><i class="fas fa-cog"></i> Settings</a>

js/crypto.js

@@ -13,8 +13,12 @@ var keymgr;
  * @returns {undefined}
  */
 function loadKeyFromLocalStorage(callback) {
+    if (typeof keymgr != "undefined") {
+        callback("Key already loaded.", true);
+        return;
+    }
     if (!inStorage("signingkey") || getStorage("signingkey") == "undefined") {
-        var pass = prompt("Generating a new signing key. Enter a password to protect it. You'll need to save this password somewhere safe; it cannot be recovered.");
+        var pass = prompt("Generating a new signing key (might take a while, be patient). Enter a password to protect it. You'll need to save this password somewhere safe; it cannot be recovered.");
         generatePrivateKey(getStorage("notary_name") + " <null@null.com>", pass, function (key) {
             if (typeof key == "undefined") {
                 callback("Could not generate key.", false);
@@ -25,7 +29,7 @@ function loadKeyFromLocalStorage(callback) {
             callback("Signing key generated.", true);
         });
     } else {
-        var pass = prompt("Enter password to unlock signing key.");
+        var pass = prompt("Enter password to unlock signing key:");
         loadPrivateKey(getStorage("signingkey"), pass, function (key) {
             if (typeof key == "undefined") {
                 callback("Could not unlock key. Password is probably incorrect.", false);
@@ -37,6 +41,16 @@ function loadKeyFromLocalStorage(callback) {
     }
 }
 
+function loadKeyFromLocalStorageWithUserFeedback() {
+    loadKeyFromLocalStorage(function (msg, ok) {
+       if (ok) {
+           alert(msg);
+       } else {
+           alert("Error: " + msg);
+       }
+    });
+}
+
 /**
  * Load a private key.
  * @param {string} armoredkey PGP private key
@@ -122,3 +136,63 @@ function generatePrivateKey(userid, passphrase, callback) {
         }
     });
 }
+
+function exportPublicKey() {
+    loadKeyFromLocalStorage(function (message, ok) {
+        if (ok) {
+            openSaveFileDialog(function (path) {
+                keymgr.export_pgp_public({}, function (err, pgp_public) {
+                    if (err) {
+                        alert("Something went wrong.");
+                    } else {
+                        writeToFile(path, pgp_public);
+                    }
+                });
+            }, "public-key.asc", ".asc");
+        } else {
+            alert("Error: " + message);
+        }
+    });
+}
+
+function exportPrivateKey() {
+    loadKeyFromLocalStorage(function (message, ok) {
+        if (ok) {
+            var pass = prompt("Enter a password to protect the backup key:");
+            openSaveFileDialog(function (path) {
+                keymgr.export_pgp_private({
+                    passphrase: pass
+                }, function (err, pgp_private) {
+                    if (err) {
+                        alert("Something went wrong.");
+                    } else {
+                        writeToFile(path, pgp_private);
+                    }
+                });
+            }, "private-key.asc", ".asc");
+        } else {
+            alert("Error: " + message);
+        }
+    });
+}
+
+function importPrivateKey() {
+    if (inStorage("signingkey") && getStorage("signingkey") != "undefined") {
+        if (!confirm("The restored key will replace the current key, which will be unrecoverable unless you made a backup. Continue?")) {
+            return;
+        }
+    }
+    openFileDialog(function (path) {
+        var keyfile = getFileAsString(path);
+        var pass = prompt("Enter password for imported key (password was set when exported):");
+        loadPrivateKey(keyfile, pass, function (key) {
+            if (typeof key == "undefined") {
+                alert("Could not import key. Password is probably incorrect.");
+                return;
+            }
+            keymgr = key;
+            setStorage("signingkey", keymgr.armored_pgp_private);
+            alert("Private key imported.");
+        });
+    }, ".asc");
+}