diff --git a/package-lock.json b/package-lock.json
index 6eabf8c..9b3cb5d 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1104,6 +1104,12 @@
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       "dev": true
     },
+    "buffer-equal-constant-time": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/buffer-equal-constant-time/-/buffer-equal-constant-time-1.0.1.tgz",
+      "integrity": "sha1-+OcRMvf/5uAaXJaXpMbz5I1cyBk=",
+      "dev": true
+    },
     "buffer-fill": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/buffer-fill/-/buffer-fill-1.0.0.tgz",
@@ -2090,6 +2096,15 @@
         "safer-buffer": "^2.1.0"
       }
     },
+    "ecdsa-sig-formatter": {
+      "version": "1.0.11",
+      "resolved": "https://registry.npmjs.org/ecdsa-sig-formatter/-/ecdsa-sig-formatter-1.0.11.tgz",
+      "integrity": "sha512-nagl3RYrbNv6kQkeJIpt6NJZy8twLB/2vtz6yN9Z4vRKHN4/QZJIEbqohALSgwKdnksuY3k5Addp5lg8sVoVcQ==",
+      "dev": true,
+      "requires": {
+        "safe-buffer": "^5.0.1"
+      }
+    },
     "ee-first": {
       "version": "1.1.1",
       "resolved": "https://registry.npmjs.org/ee-first/-/ee-first-1.1.1.tgz",
@@ -3166,7 +3181,8 @@
         "ansi-regex": {
           "version": "2.1.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "aproba": {
           "version": "1.2.0",
@@ -3187,12 +3203,14 @@
         "balanced-match": {
           "version": "1.0.0",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "brace-expansion": {
           "version": "1.1.11",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "balanced-match": "^1.0.0",
             "concat-map": "0.0.1"
@@ -3207,17 +3225,20 @@
         "code-point-at": {
           "version": "1.1.0",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "concat-map": {
           "version": "0.0.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "console-control-strings": {
           "version": "1.1.0",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "core-util-is": {
           "version": "1.0.2",
@@ -3334,7 +3355,8 @@
         "inherits": {
           "version": "2.0.3",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "ini": {
           "version": "1.3.5",
@@ -3346,6 +3368,7 @@
           "version": "1.0.0",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "number-is-nan": "^1.0.0"
           }
@@ -3360,6 +3383,7 @@
           "version": "3.0.4",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "brace-expansion": "^1.1.7"
           }
@@ -3367,12 +3391,14 @@
         "minimist": {
           "version": "0.0.8",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "minipass": {
           "version": "2.3.5",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "safe-buffer": "^5.1.2",
             "yallist": "^3.0.0"
@@ -3391,6 +3417,7 @@
           "version": "0.5.1",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "minimist": "0.0.8"
           }
@@ -3478,7 +3505,8 @@
         "number-is-nan": {
           "version": "1.0.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "object-assign": {
           "version": "4.1.1",
@@ -3490,6 +3518,7 @@
           "version": "1.4.0",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "wrappy": "1"
           }
@@ -3575,7 +3604,8 @@
         "safe-buffer": {
           "version": "5.1.2",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "safer-buffer": {
           "version": "2.1.2",
@@ -3611,6 +3641,7 @@
           "version": "1.0.2",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "code-point-at": "^1.0.0",
             "is-fullwidth-code-point": "^1.0.0",
@@ -3630,6 +3661,7 @@
           "version": "3.0.1",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "ansi-regex": "^2.0.0"
           }
@@ -3673,12 +3705,14 @@
         "wrappy": {
           "version": "1.0.2",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "yallist": {
           "version": "3.0.3",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         }
       }
     },
@@ -4756,6 +4790,32 @@
         "graceful-fs": "^4.1.6"
       }
     },
+    "jsonwebtoken": {
+      "version": "8.5.1",
+      "resolved": "https://registry.npmjs.org/jsonwebtoken/-/jsonwebtoken-8.5.1.tgz",
+      "integrity": "sha512-XjwVfRS6jTMsqYs0EsuJ4LGxXV14zQybNd4L2r0UvbVnSF9Af8x7p5MzbJ90Ioz/9TI41/hTCvznF/loiSzn8w==",
+      "dev": true,
+      "requires": {
+        "jws": "^3.2.2",
+        "lodash.includes": "^4.3.0",
+        "lodash.isboolean": "^3.0.3",
+        "lodash.isinteger": "^4.0.4",
+        "lodash.isnumber": "^3.0.3",
+        "lodash.isplainobject": "^4.0.6",
+        "lodash.isstring": "^4.0.1",
+        "lodash.once": "^4.0.0",
+        "ms": "^2.1.1",
+        "semver": "^5.6.0"
+      },
+      "dependencies": {
+        "ms": {
+          "version": "2.1.2",
+          "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.2.tgz",
+          "integrity": "sha512-sGkPx+VjMtmA6MX27oA4FBFELFCZZ4S4XqeGOXCv68tT+jb3vk/RyaKWP0PTKyWtmLSM0b+adUTEvbs1PEaH2w==",
+          "dev": true
+        }
+      }
+    },
     "jsprim": {
       "version": "1.4.1",
       "resolved": "https://registry.npmjs.org/jsprim/-/jsprim-1.4.1.tgz",
@@ -4796,6 +4856,27 @@
       "integrity": "sha512-FrLwOgm+iXrPV+5zDU6Jqu4gCRXbWEQg2O3SKONsWE4w7AXFRkryS53bpWdaL9cNol+AmR3AEYz6kn+o0fCPnw==",
       "dev": true
     },
+    "jwa": {
+      "version": "1.4.1",
+      "resolved": "https://registry.npmjs.org/jwa/-/jwa-1.4.1.tgz",
+      "integrity": "sha512-qiLX/xhEEFKUAJ6FiBMbes3w9ATzyk5W7Hvzpa/SLYdxNtng+gcurvrI7TbACjIXlsJyr05/S1oUhZrc63evQA==",
+      "dev": true,
+      "requires": {
+        "buffer-equal-constant-time": "1.0.1",
+        "ecdsa-sig-formatter": "1.0.11",
+        "safe-buffer": "^5.0.1"
+      }
+    },
+    "jws": {
+      "version": "3.2.2",
+      "resolved": "https://registry.npmjs.org/jws/-/jws-3.2.2.tgz",
+      "integrity": "sha512-YHlZCB6lMTllWDtSPHz/ZXTsi8S00usEV6v1tjq8tOUZzw7DpSDWVXjXDre6ed1w/pd495ODpHZYSdkRTsa0HA==",
+      "dev": true,
+      "requires": {
+        "jwa": "^1.4.1",
+        "safe-buffer": "^5.0.1"
+      }
+    },
     "karma": {
       "version": "4.2.0",
       "resolved": "https://registry.npmjs.org/karma/-/karma-4.2.0.tgz",
@@ -5088,7 +5169,7 @@
       }
     },
     "lanthan": {
-      "version": "git+https://github.com/ueokande/lanthan.git#fb7f641846369de5bac7762f19186d23248f0d53",
+      "version": "git+https://github.com/ueokande/lanthan.git#d7f92eb4c1c6eee3f747b4a76bdf39062b4cb58f",
       "from": "git+https://github.com/ueokande/lanthan.git#master",
       "dev": true,
       "requires": {
@@ -5300,6 +5381,48 @@
       "integrity": "sha512-DHb1ub+rMjjrxqlB3H56/6MXtm1lSksDp2rA2cNWjG8mlDUYFhUj3Di2Zn5IwSU87xLv8tNIQ7sSwE/YOX/D/Q==",
       "dev": true
     },
+    "lodash.includes": {
+      "version": "4.3.0",
+      "resolved": "https://registry.npmjs.org/lodash.includes/-/lodash.includes-4.3.0.tgz",
+      "integrity": "sha1-YLuYqHy5I8aMoeUTJUgzFISfVT8=",
+      "dev": true
+    },
+    "lodash.isboolean": {
+      "version": "3.0.3",
+      "resolved": "https://registry.npmjs.org/lodash.isboolean/-/lodash.isboolean-3.0.3.tgz",
+      "integrity": "sha1-bC4XHbKiV82WgC/UOwGyDV9YcPY=",
+      "dev": true
+    },
+    "lodash.isinteger": {
+      "version": "4.0.4",
+      "resolved": "https://registry.npmjs.org/lodash.isinteger/-/lodash.isinteger-4.0.4.tgz",
+      "integrity": "sha1-YZwK89A/iwTDH1iChAt3sRzWg0M=",
+      "dev": true
+    },
+    "lodash.isnumber": {
+      "version": "3.0.3",
+      "resolved": "https://registry.npmjs.org/lodash.isnumber/-/lodash.isnumber-3.0.3.tgz",
+      "integrity": "sha1-POdoEMWSjQM1IwGsKHMX8RwLH/w=",
+      "dev": true
+    },
+    "lodash.isplainobject": {
+      "version": "4.0.6",
+      "resolved": "https://registry.npmjs.org/lodash.isplainobject/-/lodash.isplainobject-4.0.6.tgz",
+      "integrity": "sha1-fFJqUtibRcRcxpC4gWO+BJf1UMs=",
+      "dev": true
+    },
+    "lodash.isstring": {
+      "version": "4.0.1",
+      "resolved": "https://registry.npmjs.org/lodash.isstring/-/lodash.isstring-4.0.1.tgz",
+      "integrity": "sha1-1SfftUVuynzJu5XV2ur4i6VKVFE=",
+      "dev": true
+    },
+    "lodash.once": {
+      "version": "4.1.1",
+      "resolved": "https://registry.npmjs.org/lodash.once/-/lodash.once-4.1.1.tgz",
+      "integrity": "sha1-DdOXEhPHxW34gJd9UEyI+0cal6w=",
+      "dev": true
+    },
     "lodash.unescape": {
       "version": "4.0.1",
       "resolved": "https://registry.npmjs.org/lodash.unescape/-/lodash.unescape-4.0.1.tgz",
diff --git a/package.json b/package.json
index c99a84c..4910ce9 100644
--- a/package.json
+++ b/package.json
@@ -36,6 +36,7 @@
     "eslint": "^6.2.2",
     "eslint-plugin-react": "^7.14.3",
     "html-webpack-plugin": "^3.2.0",
+    "jsonwebtoken": "^8.5.1",
     "jszip": "^3.2.2",
     "karma": "^4.2.0",
     "karma-firefox-launcher": "^1.2.0",