3.0.2

.jshintrc

@@ -0,0 +1,22 @@
+{
+    "browser": true,
+    "node": true,
+    "esversion": 11,
+    "curly": true,
+    "sub": true,
+    "bitwise": true,
+    "eqeqeq": true,
+    "forin": true,
+    "freeze": true,
+    "immed": true,
+    "latedef": "nofunc",
+    "nonbsp": true,
+    "nonew": true,
+    "plusplus": true,
+    "undef": true,
+    "unused": "vars",
+    "strict": true,
+    "maxdepth": 3,
+    "maxstatements": 100,
+    "maxcomplexity": 10
+}

.prettierrc.json

@@ -0,0 +1,7 @@
+{
+  "bracketSpacing": true,
+  "printWidth": 120,
+  "tabWidth": 4,
+  "trailingComma": "none",
+  "useTabs": false
+}

CHANGELOG.md

@@ -0,0 +1,11 @@
+# v3.0.0
+
+**Breaking Change**: Standardize error `message`s (now they're more client-friendly).
+
+# v2.1.0
+
+Feature: Add `code`, `status`, and `details` to errors.
+
+# v2.0.0
+
+**Breaking Change**: require `issuers` array (rather than `["*"]` by default).

README.md

@@ -1,4 +1,4 @@
-# keyfetch
+# [keyfetch](https://git.rootprojects.org/root/keyfetch.js)
 
 Lightweight support for fetching JWKs.
 
@@ -9,17 +9,28 @@ Fetches JSON native JWKs and exposes them as PEMs that can be consumed by the `j
 
 Works great for
 
-* [x] `jsonwebtoken` (Auth0)
+-   [x] `jsonwebtoken` (Auth0)
-* [x] OIDC (OpenID Connect)
+-   [x] OIDC (OpenID Connect)
-* [x] .well-known/jwks.json (Auth0)
+-   [x] .well-known/jwks.json (Auth0, Okta)
-* [x] Other JWKs URLs
+-   [x] Other JWKs URLs
 
 Crypto Support
 
-* [x] JWT verification
+-   [x] JWT verification
-* [x] RSA (all variants)
+-   [x] RSA (all variants)
-* [x] EC / ECDSA (NIST variants P-256, P-384)
+-   [x] EC / ECDSA (NIST variants P-256, P-384)
-* [ ] esoteric variants (excluded to keep the code featherweight and secure)
+-   [x] Sane error codes
+-   [ ] esoteric variants (excluded to keep the code featherweight and secure)
+
+# Table of Contents
+
+-   Install
+-   Usage
+-   API
+    -   Auth0 / Okta
+    -   OIDC
+-   Errors
+-   Change Log
 
 # Install
 
@@ -32,73 +43,71 @@ npm install --save keyfetch
 Retrieve a key list of keys:
 
 ```js
-var keyfetch = require('keyfetch');
+var keyfetch = require("keyfetch");
 
 keyfetch.oidcJwks("https://example.com/").then(function (results) {
-  results.forEach(function (result) {
+    results.forEach(function (result) {
-    console.log(result.jwk);
+        console.log(result.jwk);
-    console.log(result.thumprint);
+        console.log(result.thumprint);
-    console.log(result.pem);
+        console.log(result.pem);
-  });
+    });
 });
 ```
 
 Quick JWT verification (for authentication):
 
 ```js
-var keyfetch = require('keyfetch');
+var keyfetch = require("keyfetch");
-var jwt = '...';
+var jwt = "...";
 
 keyfetch.jwt.verify(jwt).then(function (decoded) {
-  console.log(decoded);
+    console.log(decoded);
 });
 ```
 
 JWT verification (for authorization):
 
 ```js
-var options = { issuers: ['https://example.com/'], claims: { role: 'admin' } };
+var options = { issuers: ["https://example.com/"], claims: { role: "admin" } };
 keyfetch.jwt.verify(jwt, options).then(function (decoded) {
-  console.log(decoded);
+    console.log(decoded);
 });
 ```
 
 Verify a JWT with `jsonwebtoken`:
 
 ```js
-var keyfetch = require('keyfetch');
+var keyfetch = require("keyfetch");
-var jwt = require('jsonwebtoken');
+var jwt = require("jsonwebtoken");
 var auth = "..."; // some JWT
-var token = jwt.decode(auth, { json: true, complete: true })
+var token = jwt.decode(auth, { json: true, complete: true });
 
 if (!isTrustedIssuer(token.payload.iss)) {
-  throw new Error("untrusted issuer");
+    throw new Error("untrusted issuer");
 }
 
-keyfetch.oidcJwk(
+keyfetch.oidcJwk(token.header.kid, token.payload.iss).then(function (result) {
-  token.header.kid
+    console.log(result.jwk);
-, token.payload.iss
+    console.log(result.thumprint);
-).then(function (result) {
+    console.log(result.pem);
-  console.log(result.jwk);
-  console.log(result.thumprint);
-  console.log(result.pem);
 
-  jwt.jwt.verify(jwt, { jwk: result.jwk });
+    jwt.jwt.verify(jwt, { jwk: result.jwk });
 });
 ```
 
-*Note*: You might implement `isTrustedIssuer` one of these:
+_Note_: You might implement `isTrustedIssuer` one of these:
 
 ```js
 function isTrustedIssuer(iss) {
-  return -1 !== [ 'https://partner.com/', 'https://auth0.com/'].indexOf(iss);
+    return -1 !== ["https://partner.com/", "https://auth0.com/"].indexOf(iss);
 }
 ```
 
 ```js
 function isTrustedIssuer(iss) {
-  return /^https:/.test(iss) &&         // must be a secure domain
+    return (
-    /(\.|^)example\.com$/.test(iss);    // can be example.com or any subdomain
+        /^https:/.test(iss) && /(\.|^)example\.com$/.test(iss) // must be a secure domain
+    ); // can be example.com or any subdomain
 }
 ```
 
@@ -115,12 +124,12 @@ Retrieves keys from a URL such as `https://example.com/jwks/` with the format `{
 and returns the array of keys (as well as thumbprint and jwk-to-pem).
 
 ```js
-keyfetch.jwks(jwksUrl)
+keyfetch.jwks(jwksUrl);
 // Promises [ { jwk, thumbprint, pem } ] or fails
 ```
 
 ```js
-keyfetch.jwk(id, jwksUrl)
+keyfetch.jwk(id, jwksUrl);
 // Promises { jwk, thumbprint, pem } or fails
 ```
 
@@ -130,12 +139,12 @@ If `https://example.com/` is used as `issuerUrl` it will resolve to
 `https://example.com/.well-known/jwks.json` and return the keys.
 
 ```js
-keyfetch.wellKnownJwks(issuerUrl)
+keyfetch.wellKnownJwks(issuerUrl);
 // Promises [ { jwk, thumbprint, pem } ] or fails
 ```
 
 ```js
-keyfetch.wellKnownJwk(id, issuerUrl)
+keyfetch.wellKnownJwk(id, issuerUrl);
 // Promises { jwk, thumbprint, pem } or fails
 ```
 
@@ -145,12 +154,12 @@ If `https://example.com/` is used as `issuerUrl` then it will first resolve to
 `https://example.com/.well-known/openid-configuration` and then follow `jwks_uri` to return the keys.
 
 ```js
-keyfetch.oidcJwks(issuerUrl)
+keyfetch.oidcJwks(issuerUrl);
 // Promises [ { jwk, thumbprint, pem } ] or fails
 ```
 
 ```js
-keyfetch.oidcJwk(id, issuerUrl)
+keyfetch.oidcJwk(id, issuerUrl);
 // Promises { jwk, thumbprint, pem } or fails
 ```
 
@@ -161,8 +170,8 @@ This can accept a _JWT string_ (compact JWS) or a _decoded JWT object_ (JWS).
 This can be used purely for verifying pure authentication tokens, as well as authorization tokens.
 
 ```js
-keyfetch.jwt.verify(jwt, { strategy: 'oidc' }).then(function (verified) {
+keyfetch.jwt.verify(jwt, { strategy: "oidc" }).then(function (verified) {
-  /*
+    /*
     { protected: '...'  // base64 header
     , payload: '...'    // base64 payload
     , signature: '...'  // base64 signature
@@ -173,26 +182,27 @@ keyfetch.jwt.verify(jwt, { strategy: 'oidc' }).then(function (verified) {
 });
 ```
 
-When used for authorization, it's important to specify which `issuers` are allowed
+When used for authorization, it's important to specify a limited set of trusted `issuers`. \
-(otherwise anyone can create a valid token with whatever any claims they want).
+When using for federated authentication you may set `issuers = ["*"]` - but **DO NOT** trust claims such as `email` and `email_verified`.
 
 If your authorization `claims` can be expressed as exact string matches, you can specify those too.
 
 ```js
 keyfetch.jwt.verify(jwt, {
-  strategy: 'oidc'
+  strategy: 'oidc',
-, issuers: [ 'https://example.com/' ]
+  issuers: [ 'https://example.com/' ],
-, claims: { role: 'admin', sub: 'abc', group: 'xyz' }
+  //iss: 'https://example.com/',
+  claims: { role: 'admin', sub: 'abc', group: 'xyz' }
 }).then(function (verified) {
-
 ```
 
-* `strategy` may be `oidc` (default) , `auth0`, or a direct JWKs url.
+-   `strategy` may be `oidc` (default) , `auth0`, or a direct JWKs url.
-* `issuers` must be a list of https urls (though http is allowed for things like Docker swarm)
+-   `issuers` must be a list of https urls (though http is allowed for things like Docker swarm), or '\*'
-* `claims` is an object with arbitrary keys (i.e. everything except for the standard `iat`, `exp`, `jti`, etc)
+-   `iss` is like `issuers`, but only one
-* `exp` may be set to `false` if you're validating on your own (i.e. allowing time drift leeway)
+-   `claims` is an object with arbitrary keys (i.e. everything except for the standard `iat`, `exp`, `jti`, etc)
-* `jwks` can be used to specify a list of allowed public key rather than fetching them (i.e. for offline unit tests)
+-   `exp` may be set to `false` if you're validating on your own (i.e. allowing time drift leeway)
-* `jwk` same as above, but a single key rather than a list
+-   `jwks` can be used to specify a list of allowed public key rather than fetching them (i.e. for offline unit tests)
+-   `jwk` same as above, but a single key rather than a list
 
 ### Decode JWT
 
@@ -216,19 +226,19 @@ It's easier just to show the code than to explain the example.
 
 ```js
 keyfetch.jwt.decode = function (jwt) {
-  // Unpack JWS from "compact" form
+    // Unpack JWS from "compact" form
-  var parts = jwt.split('.');
+    var parts = jwt.split(".");
-  var obj = {
+    var obj = {
-    protected: parts[0]
+        protected: parts[0],
-  , payload: parts[1]
+        payload: parts[1],
-  , signature: parts[2]
+        signature: parts[2]
-  };
+    };
 
-  // Decode JWT properties from JWS as unordered objects
+    // Decode JWT properties from JWS as unordered objects
-  obj.header = JSON.parse(Buffer.from(obj.protected, 'base64'));
+    obj.header = JSON.parse(Buffer.from(obj.protected, "base64"));
-  obj.claims = JSON.parse(Buffer.from(obj.payload, 'base64'));
+    obj.claims = JSON.parse(Buffer.from(obj.payload, "base64"));
 
-  return obj;
+    return obj;
 };
 ```
 
@@ -236,16 +246,63 @@ keyfetch.jwt.decode = function (jwt) {
 
 ```js
 keyfetch.init({
-  // set all keys at least 1 hour (regardless of jwk.exp)
+    // set all keys at least 1 hour (regardless of jwk.exp)
-  mincache: 1 * 60 * 60
+    mincache: 1 * 60 * 60,
 
-  // expire each key after 3 days (regardless of jwk.exp)
+    // expire each key after 3 days (regardless of jwk.exp)
-, maxcache: 3 * 24 * 60 * 60
+    maxcache: 3 * 24 * 60 * 60,
 
-  // re-fetch a key up to 15 minutes before it expires (only if used)
+    // re-fetch a key up to 15 minutes before it expires (only if used)
-, staletime: 15 * 60
+    staletime: 15 * 60
-})
+});
 ```
 
 There is no background task to cleanup expired keys as of yet.
 For now you can limit the number of keys fetched by having a simple whitelist.
+
+# Errors
+
+`JSON.stringify()`d errors look like this:
+
+```js
+{
+  code: "INVALID_JWT",
+  status: 401,
+  details: [ "jwt.claims.exp = 1634804500", "DEBUG: helpful message" ]
+  message: "token's 'exp' has passed or could not parsed: 1634804500"
+}
+```
+
+SemVer Compatibility:
+
+-   `code` & `status` will remain the same.
+-   `message` is **NOT** included in the semver compatibility guarantee (we intend to make them more client-friendly), neither is `detail` at this time (but it will be once we decide on what it should be).
+-   `details` may be added to, but not subtracted from
+
+| Hint              | Code          | Status | Message (truncated)                                    |
+| ----------------- | ------------- | ------ | ------------------------------------------------------ |
+| bad gateway       | BAD_GATEWAY   | 502    | The auth token could not be verified because our se... |
+| insecure issuer   | MALFORMED_JWT | 400    | The auth token could not be verified because our se... |
+| parse error       | MALFORMED_JWT | 400    | The auth token could not be verified because it is ... |
+| no issuer         | MALFORMED_JWT | 400    | The auth token could not be verified because it doe... |
+| malformed exp     | MALFORMED_JWT | 400    | The auth token could not be verified because it's e... |
+| expired           | INVALID_JWT   | 401    | The auth token is expired. To try again, go to the ... |
+| inactive          | INVALID_JWT   | 401    | The auth token isn't valid yet. It's activation dat... |
+| bad signature     | INVALID_JWT   | 401    | The auth token did not pass verification because it... |
+| jwk not found old | INVALID_JWT   | 401    | The auth token did not pass verification because ou... |
+| jwk not found     | INVALID_JWT   | 401    | The auth token did not pass verification because ou... |
+| no jwkws uri      | INVALID_JWT   | 401    | The auth token did not pass verification because it... |
+| unknown issuer    | INVALID_JWT   | 401    | The auth token did not pass verification because it... |
+| failed claims     | INVALID_JWT   | 401    | The auth token did not pass verification because it... |
+
+# Change Log
+
+Minor Breaking changes (with a major version bump):
+
+-   v3.0.0
+    -   reworked error messages (also available in v2.1.0 as `client_message`)
+    -   started using `let` and template strings (drops _really_ old node compat)
+-   v2.0.0
+    -   changes from the default `issuers = ["*"]` to requiring that an issuer (or public jwk for verification) is specified
+
+See other changes in [CHANGELOG.md](./CHANGELOG.md).

keyfetch-test.js

@@ -1,80 +1,151 @@
-'use strict';
+"use strict";
 
-var keyfetch = require('./keyfetch.js');
+var keyfetch = require("./keyfetch.js");
 var testIss = "https://example.auth0.com";
 
 keyfetch.init({});
-keyfetch.oidcJwks(testIss).then(function (hits) {
+keyfetch
-  keyfetch._clear();
+    .oidcJwks(testIss)
-  //console.log(hits);
+    .then(function (hits) {
-  return keyfetch.oidcJwk(hits[0].thumbprint, testIss).then(function () {
+        keyfetch._clear();
-    return keyfetch.oidcJwk(hits[0].thumbprint, testIss).then(function (/*jwk*/) {
+        //console.log(hits);
-      //console.log(jwk);
+        return keyfetch.oidcJwk(hits[0].thumbprint, testIss).then(function () {
+            return keyfetch.oidcJwk(hits[0].thumbprint, testIss).then(function (/*jwk*/) {
+                //console.log(jwk);
+            });
+        });
+    })
+    .then(function () {
+        console.log("Fetching PASSES");
+    })
+    .catch(function (err) {
+        console.error("NONE SHALL PASS!");
+        console.error(err);
+        process.exit(1);
     });
-  });
-}).then(function () {
-  console.log("Fetching PASSES");
-}).catch(function (err) {
-  console.error("NONE SHALL PASS!");
-  console.error(err);
-  process.exit(1);
-});
 
 /*global Promise*/
-var keypairs = require('keypairs.js');
+var keypairs = require("keypairs");
 keypairs.generate().then(function (pair) {
-  return Promise.all([
+    var iss = "https://example.com/";
-    keypairs.signJwt({
+    return Promise.all([
-      jwk: pair.private, iss: 'https://example.com/', sub: 'mikey', exp: '1h'
+        keypairs
-    }).then(function (jwt) {
+            .signJwt({
-      return Promise.all([
+                jwk: pair.private,
-        keyfetch.jwt.verify(jwt, { jwk: pair.public }).then(function (verified) {
+                iss: iss,
-          if (!(verified.claims && verified.claims.exp)) {
+                sub: "mikey",
-            throw new Error("malformed decoded token");
+                exp: "1h"
-          }
+            })
+            .then(function (jwt) {
+                return Promise.all([
+                    keyfetch.jwt.verify(jwt, { jwk: pair.public, iss: "*" }).then(function (verified) {
+                        if (!(verified.claims && verified.claims.exp)) {
+                            throw new Error("malformed decoded token");
+                        }
+                    }),
+                    keyfetch.jwt
+                        .verify(keyfetch.jwt.decode(jwt), { jwk: pair.public, iss: iss })
+                        .then(function (verified) {
+                            if (!(verified.claims && verified.claims.exp)) {
+                                throw new Error("malformed decoded token");
+                            }
+                        }),
+                    keyfetch.jwt.verify(jwt, { jwks: [pair.public], issuers: [iss] }),
+                    keyfetch.jwt.verify(jwt, {
+                        jwk: pair.public,
+                        issuers: ["https://example.com/"]
+                    }),
+                    keyfetch.jwt.verify(jwt, {
+                        jwk: pair.public,
+                        issuers: ["https://example.com"]
+                    }),
+                    keyfetch.jwt.verify(jwt, {
+                        jwk: pair.public,
+                        issuers: ["example.com"]
+                    }),
+                    keyfetch.jwt.verify(jwt, {
+                        jwk: pair.public,
+                        issuers: ["example.com/"]
+                    }),
+                    keyfetch.jwt.verify(jwt, {
+                        jwk: pair.public,
+                        issuers: ["*"]
+                    }),
+                    keyfetch.jwt
+                        .verify(jwt, {
+                            jwk: pair.public,
+                            issuers: ["http://example.com"]
+                        })
+                        .then(e("bad scheme"))
+                        .catch(throwIfNotExpected),
+                    keyfetch.jwt
+                        .verify(jwt, {
+                            jwk: pair.public,
+                            issuers: ["https://www.example.com"]
+                        })
+                        .then(e("bad prefix"))
+                        .catch(throwIfNotExpected),
+                    keyfetch.jwt
+                        .verify(jwt, {
+                            jwk: pair.public,
+                            issuers: ["https://wexample.com"]
+                        })
+                        .then(e("bad sld"))
+                        .catch(throwIfNotExpected),
+                    keyfetch.jwt
+                        .verify(jwt, {
+                            jwk: pair.public,
+                            issuers: ["https://example.comm"]
+                        })
+                        .then(e("bad tld"))
+                        .catch(throwIfNotExpected),
+                    keyfetch.jwt.verify(jwt, {
+                        jwk: pair.public,
+                        claims: { iss: "https://example.com/" }
+                    }),
+                    keyfetch.jwt
+                        .verify(jwt, {
+                            jwk: pair.public,
+                            claims: { iss: "https://example.com" }
+                        })
+                        .then(e("inexact claim"))
+                        .catch(throwIfNotExpected)
+                ]);
+            }),
+        keypairs
+            .signJwt({
+                jwk: pair.private,
+                iss: false,
+                sub: "mikey",
+                exp: "1h"
+            })
+            .then(function (jwt) {
+                return Promise.all([
+                    // test that the old behavior of defaulting to '*' still works
+                    keyfetch.jwt
+                        .verify(jwt, { jwk: pair.public })
+                        .then(e("should have issued security warning about allow all by default"))
+                        .catch(throwIfNotExpected),
+                    keyfetch.jwt.verify(jwt, { jwk: pair.public, issuers: ["*"] }),
+                    keyfetch.jwt.verify(jwt).then(e("should have an issuer")).catch(throwIfNotExpected),
+                    keyfetch.jwt
+                        .verify(jwt, {
+                            jwk: pair.public,
+                            issuers: ["https://example.com/"]
+                        })
+                        .then(e("fail when issuer specified and doesn't exist"))
+                        .catch(throwIfNotExpected)
+                ]);
+            })
+    ])
+        .then(function () {
+            console.log("JWT PASSES");
         })
-      , keyfetch.jwt.verify(keyfetch.jwt.decode(jwt), { jwk: pair.public }).then(function (verified) {
+        .catch(function (err) {
-          if (!(verified.claims && verified.claims.exp)) {
+            console.error("NONE SHALL PASS!");
-            throw new Error("malformed decoded token");
+            console.error(err);
-          }
+            process.exit(1);
-        })
+        });
-      , keyfetch.jwt.verify(jwt, { jwks: [pair.public] })
-      , keyfetch.jwt.verify(jwt, { jwk: pair.public, issuers: ['https://example.com/'] })
-      , keyfetch.jwt.verify(jwt, { jwk: pair.public, issuers: ['https://example.com'] })
-      , keyfetch.jwt.verify(jwt, { jwk: pair.public, issuers: ['example.com'] })
-      , keyfetch.jwt.verify(jwt, { jwk: pair.public, issuers: ['example.com/'] })
-      , keyfetch.jwt.verify(jwt, { jwk: pair.public, issuers: ['*'] })
-      , keyfetch.jwt.verify(jwt, { jwk: pair.public, issuers: ['http://example.com'] })
-          .then(e("bad scheme")).catch(throwIfNotExpected)
-      , keyfetch.jwt.verify(jwt, { jwk: pair.public, issuers: ['https://www.example.com'] })
-          .then(e("bad prefix")).catch(throwIfNotExpected)
-      , keyfetch.jwt.verify(jwt, { jwk: pair.public, issuers: ['https://wexample.com'] })
-          .then(e("bad sld")).catch(throwIfNotExpected)
-      , keyfetch.jwt.verify(jwt, { jwk: pair.public, issuers: ['https://example.comm'] })
-          .then(e("bad tld")).catch(throwIfNotExpected)
-      , keyfetch.jwt.verify(jwt, { jwk: pair.public, claims: { iss: 'https://example.com/' } })
-      , keyfetch.jwt.verify(jwt, { jwk: pair.public, claims: { iss: 'https://example.com' } })
-          .then(e("inexact claim")).catch(throwIfNotExpected)
-      ]);
-    })
-  , keypairs.signJwt({
-      jwk: pair.private, iss: false, sub: 'mikey', exp: '1h'
-    }).then(function (jwt) {
-      return Promise.all([
-        keyfetch.jwt.verify(jwt, { jwk: pair.public })
-      , keyfetch.jwt.verify(jwt)
-          .then(e("should have an issuer")).catch(throwIfNotExpected)
-      , keyfetch.jwt.verify(jwt, { jwk: pair.public, issuers: ['https://example.com/'] })
-          .then(e("fail when issuer specified and doesn't exist")).catch(throwIfNotExpected)
-      ]);
-    })
-  ]).then(function () {
-    console.log("JWT PASSES");
-  }).catch(function (err) {
-    console.error("NONE SHALL PASS!");
-    console.error(err);
-    process.exit(1);
-  });
 });
 /*
 var jwt = '...';
@@ -84,8 +155,10 @@ keyfetch.verify({ jwt: jwt }).catch(function (err) {
 */
 
 function e(msg) {
-  return new Error("ETEST: " + msg);
+    return new Error("ETEST: " + msg);
 }
 function throwIfNotExpected(err) {
-  if ("ETEST" === err.message.slice(0, 5)) { throw err; }
+    if ("ETEST" === err.message.slice(0, 5)) {
+        throw err;
+    }
 }

keyfetch.js

@@ -1,160 +1,163 @@
-'use strict';
+"use strict";
 
 var keyfetch = module.exports;
 
-var promisify = require('util').promisify;
+var request = require("@root/request").defaults({
-var requestAsync = promisify(require('@coolaj86/urequest'));
+    userAgent: "keyfetch/v2.1.0"
-var Rasha = require('rasha');
+});
-var Eckles = require('eckles');
+var Rasha = require("rasha");
+var Eckles = require("eckles");
 var mincache = 1 * 60 * 60;
 var maxcache = 3 * 24 * 60 * 60;
 var staletime = 15 * 60;
 var keyCache = {};
 
-/*global Promise*/
+var Errors = require("./lib/errors.js");
-function checkMinDefaultMax(opts, key, n, d, x) {
+
-  var i = opts[key];
+async function requestAsync(req) {
-  if (!i && 0 !== i) { return d; }
+    var resp = await request(req).catch(Errors.BAD_GATEWAY);
-  if (i >= n && i >= x) {
+
-    return parseInt(i, 10);
+    // differentiate potentially temporary server errors from 404
-  } else {
+    if (!resp.ok && (resp.statusCode >= 500 || resp.statusCode < 200)) {
-    throw new Error("opts." + key + " should be at least " + n + " and at most " + x + ", not " + i);
+        throw Errors.BAD_GATEWAY({ response: resp });
-  }
+    }
+
+    return resp;
 }
 
+function checkMinDefaultMax(opts, key, n, d, x) {
+    var i = opts[key];
+    if (!i && 0 !== i) {
+        return d;
+    }
+    if (i >= n && i >= x) {
+        return parseInt(i, 10);
+    } else {
+        throw Errors.DEVELOPER_ERROR("opts." + key + " should be at least " + n + " and at most " + x + ", not " + i);
+    }
+}
+
+keyfetch._errors = Errors;
+
 keyfetch._clear = function () {
-  keyCache = {};
+    keyCache = {};
 };
 keyfetch.init = function (opts) {
-  mincache = checkMinDefaultMax(opts, 'mincache',
+    mincache = checkMinDefaultMax(opts, "mincache", 1 * 60, mincache, 31 * 24 * 60 * 60);
-    1 * 60,
+    maxcache = checkMinDefaultMax(opts, "maxcache", 1 * 60 * 60, maxcache, 31 * 24 * 60 * 60);
-    mincache,
+    staletime = checkMinDefaultMax(opts, "staletime", 1 * 60, staletime, 31 * 24 * 60 * 60);
-    31 * 24 * 60 * 60
-  );
-  maxcache = checkMinDefaultMax(opts, 'maxcache',
-    1 * 60 * 60,
-    maxcache,
-    31 * 24 * 60 * 60
-  );
-  staletime = checkMinDefaultMax(opts, 'staletime',
-    1 * 60,
-    staletime,
-    31 * 24 * 60 * 60
-  );
 };
-keyfetch._oidc = function (iss) {
+keyfetch._oidc = async function (iss) {
-  return Promise.resolve().then(function () {
+    var url = normalizeIss(iss) + "/.well-known/openid-configuration";
-    return requestAsync({
+    var resp = await requestAsync({
-      url: normalizeIss(iss) + '/.well-known/openid-configuration'
+        url: url,
-    , json: true
+        json: true
-    }).then(function (resp) {
-      var oidcConf = resp.body;
-      if (!oidcConf.jwks_uri) {
-        throw new Error("Failed to retrieve openid configuration");
-      }
-      return oidcConf;
     });
-  });
+
+    var oidcConf = resp.body;
+    if (!oidcConf.jwks_uri) {
+        throw Errors.NO_JWKS_URI(url);
+    }
+    return oidcConf;
 };
-keyfetch._wellKnownJwks = function (iss) {
+keyfetch._wellKnownJwks = async function (iss) {
-  return Promise.resolve().then(function () {
+    return keyfetch._jwks(normalizeIss(iss) + "/.well-known/jwks.json");
-    return keyfetch._jwks(normalizeIss(iss) + '/.well-known/jwks.json');
-  });
 };
-keyfetch._jwks = function (iss) {
+keyfetch._jwks = async function (iss) {
-  return requestAsync({ url: iss, json: true }).then(function (resp) {
+    var resp = await requestAsync({ url: iss, json: true });
-    return Promise.all(resp.body.keys.map(function (jwk) {
+
-      // EC keys have an x values, whereas RSA keys do not
+    return Promise.all(
-      var Keypairs = jwk.x ? Eckles : Rasha;
+        resp.body.keys.map(async function (jwk) {
-      return Keypairs.thumbprint({ jwk: jwk }).then(function (thumbprint) {
+            // EC keys have an x values, whereas RSA keys do not
-        return Keypairs.export({ jwk: jwk }).then(function (pem) {
+            var Keypairs = jwk.x ? Eckles : Rasha;
-          var cacheable = {
+            var thumbprint = await Keypairs.thumbprint({ jwk: jwk });
-            jwk: jwk
+            var pem = await Keypairs.export({ jwk: jwk });
-          , thumbprint: thumbprint
+            var cacheable = {
-          , pem: pem
+                jwk: jwk,
-          };
+                thumbprint: thumbprint,
-          return cacheable;
+                pem: pem
-        });
+            };
-      });
+            return cacheable;
-    }));
+        })
-  });
+    );
 };
-keyfetch.jwks = function (jwkUrl) {
+keyfetch.jwks = async function (jwkUrl) {
-  // TODO DRY up a bit
-  return keyfetch._jwks(jwkUrl).then(function (results) {
-    return Promise.all(results.map(function (result) {
-      return keyfetch._setCache(result.jwk.iss || jwkUrl, result);
-    })).then(function () {
-      // cacheable -> hit (keep original externally immutable)
-      return JSON.parse(JSON.stringify(results));
-    });
-  });
-};
-keyfetch.wellKnownJwks = function (iss) {
-  // TODO DRY up a bit
-  return keyfetch._wellKnownJwks(iss).then(function (results) {
-    return Promise.all(results.map(function (result) {
-      return keyfetch._setCache(result.jwk.iss || iss, result);
-    })).then(function () {
-      // result -> hit (keep original externally immutable)
-      return JSON.parse(JSON.stringify(results));
-    });
-  });
-};
-keyfetch.oidcJwks = function (iss) {
-  return keyfetch._oidc(iss).then(function (oidcConf) {
     // TODO DRY up a bit
-    return keyfetch._jwks(oidcConf.jwks_uri).then(function (results) {
+    var results = await keyfetch._jwks(jwkUrl);
-      return Promise.all(results.map(function (result) {
+    await Promise.all(
-        return keyfetch._setCache(result.jwk.iss || iss, result);
+        results.map(async function (result) {
-      })).then(function () {
+            return keyfetch._setCache(result.jwk.iss || jwkUrl, result);
-        // result -> hit (keep original externally immutable)
+        })
-        return JSON.parse(JSON.stringify(results));
+    );
-      });
+    // cacheable -> hit (keep original externally immutable)
-    });
+    return JSON.parse(JSON.stringify(results));
-  });
+};
+keyfetch.wellKnownJwks = async function (iss) {
+    // TODO DRY up a bit
+    var results = await keyfetch._wellKnownJwks(iss);
+    await Promise.all(
+        results.map(async function (result) {
+            return keyfetch._setCache(result.jwk.iss || iss, result);
+        })
+    );
+    // result -> hit (keep original externally immutable)
+    return JSON.parse(JSON.stringify(results));
+};
+keyfetch.oidcJwks = async function (iss) {
+    var oidcConf = await keyfetch._oidc(iss);
+    // TODO DRY up a bit
+    var results = await keyfetch._jwks(oidcConf.jwks_uri);
+    await Promise.all(
+        results.map(async function (result) {
+            return keyfetch._setCache(result.jwk.iss || iss, result);
+        })
+    );
+    // result -> hit (keep original externally immutable)
+    return JSON.parse(JSON.stringify(results));
 };
 function checkId(id) {
-  return function (results) {
+    return function (results) {
-    var result = results.filter(function (result) {
+        var result = results.filter(function (result) {
-      // we already checked iss above
+            // we already checked iss above
-      return result.jwk.kid === id || result.thumbprint === id;
+            return result.jwk.kid === id || result.thumbprint === id;
-    })[0];
+        })[0];
 
-    if (!result) {
+        if (!result) {
-      throw new Error("No JWK found by kid or thumbprint '" + id + "'");
+            throw Errors.JWK_NOT_FOUND(id);
-    }
+        }
-    return result;
+        return result;
-  };
+    };
 }
-keyfetch.oidcJwk = function (id, iss) {
+keyfetch.oidcJwk = async function (id, iss) {
-  return keyfetch._checkCache(id, iss).then(function (hit) {
+    var hit = await keyfetch._checkCache(id, iss);
-    if (hit) { return hit; }
+    if (hit) {
+        return hit;
+    }
     return keyfetch.oidcJwks(iss).then(checkId(id));
-  });
 };
-keyfetch.wellKnownJwk = function (id, iss) {
+keyfetch.wellKnownJwk = async function (id, iss) {
-  return keyfetch._checkCache(id, iss).then(function (hit) {
+    var hit = await keyfetch._checkCache(id, iss);
-    if (hit) { return hit; }
+    if (hit) {
+        return hit;
+    }
     return keyfetch.wellKnownJwks(iss).then(checkId(id));
-  });
 };
-keyfetch.jwk = function (id, jwksUrl) {
+keyfetch.jwk = async function (id, jwksUrl) {
-  return keyfetch._checkCache(id, jwksUrl).then(function (hit) {
+    var hit = await keyfetch._checkCache(id, jwksUrl);
-    if (hit) { return hit; }
+    if (hit) {
+        return hit;
+    }
     return keyfetch.jwks(jwksUrl).then(checkId(id));
-  });
 };
-keyfetch._checkCache = function (id, iss) {
+keyfetch._checkCache = async function (id, iss) {
-  return Promise.resolve().then(function () {
     // We cache by thumbprint and (kid + '@' + iss),
     // so it's safe to check without appending the issuer
     var hit = keyCache[id];
     if (!hit) {
-      hit = keyCache[id + '@' + normalizeIss(iss)];
+        hit = keyCache[id + "@" + normalizeIss(iss)];
     }
     if (!hit) {
-      return null;
+        return null;
     }
 
     var now = Math.round(Date.now() / 1000);
@@ -162,232 +165,282 @@ keyfetch._checkCache = function (id, iss) {
     // not guarding number checks since we know that we
     // set 'now' and 'expiresAt' correctly elsewhere
     if (left > staletime) {
-      return JSON.parse(JSON.stringify(hit));
+        return JSON.parse(JSON.stringify(hit));
     }
     if (left > 0) {
-      return JSON.parse(JSON.stringify(hit));
+        return JSON.parse(JSON.stringify(hit));
     }
     return null;
-  });
 };
 keyfetch._setCache = function (iss, cacheable) {
-  // force into a number
+    // force into a number
-  var expiresAt = parseInt(cacheable.jwk.exp, 10) || 0;
+    var expiresAt = parseInt(cacheable.jwk.exp, 10) || 0;
-  var now = Date.now() / 1000;
+    var now = Date.now() / 1000;
-  var left = expiresAt - now;
+    var left = expiresAt - now;
 
-  // TODO maybe log out when any of these non-ideal cases happen?
+    // TODO maybe log out when any of these non-ideal cases happen?
-  if (!left) {
+    if (!left) {
-    expiresAt = now + maxcache;
+        expiresAt = now + maxcache;
-  } else if (left < mincache) {
+    } else if (left < mincache) {
-    expiresAt = now + mincache;
+        expiresAt = now + mincache;
-  } else if (left > maxcache) {
+    } else if (left > maxcache) {
-    expiresAt = now + maxcache;
+        expiresAt = now + maxcache;
-  }
+    }
 
-  // cacheable = { jwk, thumprint, pem }
+    // cacheable = { jwk, thumprint, pem }
-  cacheable.createdAt = now;
+    cacheable.createdAt = now;
-  cacheable.expiresAt = expiresAt;
+    cacheable.expiresAt = expiresAt;
-  keyCache[cacheable.thumbprint] = cacheable;
+    keyCache[cacheable.thumbprint] = cacheable;
-  keyCache[cacheable.jwk.kid + '@' + normalizeIss(iss)] = cacheable;
+    keyCache[cacheable.jwk.kid + "@" + normalizeIss(iss)] = cacheable;
 };
 
 function normalizeIss(iss) {
-  // We definitely don't want false negatives stemming
+    if (!iss) {
-  // from https://example.com vs https://example.com/
+        throw Errors.NO_ISSUER();
-  // We also don't want to allow insecure issuers
+    }
-  if (/^http:/.test(iss) && !process.env.KEYFETCH_ALLOW_INSECURE_HTTP) {
+
-    // note, we wrap some things in promises just so we can throw here
+    // We definitely don't want false negatives stemming
-    throw new Error("'" + iss + "' is NOT secure. Set env 'KEYFETCH_ALLOW_INSECURE_HTTP=true' to allow for testing.");
+    // from https://example.com vs https://example.com/
-  }
+    // We also don't want to allow insecure issuers
-  return iss.replace(/\/$/, '');
+    if (/^http:/.test(iss) && !process.env.KEYFETCH_ALLOW_INSECURE_HTTP) {
+        // note, we wrap some things in promises just so we can throw here
+        throw Errors.INSECURE_ISSUER(iss);
+    }
+    return iss.replace(/\/$/, "");
 }
 
 keyfetch.jwt = {};
 keyfetch.jwt.decode = function (jwt) {
-  var parts = jwt.split('.');
+    try {
-  // JWS
+        var parts = jwt.split(".");
-  var obj = {
+        // JWS
-    protected: parts[0]
+        var obj = { protected: parts[0], payload: parts[1], signature: parts[2] };
-  , payload: parts[1]
+        // JWT
-  , signature: parts[2]
+        obj.header = JSON.parse(Buffer.from(obj.protected, "base64"));
-  };
+        obj.claims = JSON.parse(Buffer.from(obj.payload, "base64"));
-  // JWT
+        return obj;
-  obj.header = JSON.parse(Buffer.from(obj.protected, 'base64'));
+    } catch (e) {
-  obj.claims = JSON.parse(Buffer.from(obj.payload, 'base64'));
+        var err = Errors.PARSE_ERROR(jwt);
-  return obj;
+        err.details = e.message;
+        throw err;
+    }
 };
-keyfetch.jwt.verify = function (jwt, opts) {
+keyfetch.jwt.verify = async function (jwt, opts) {
-  if (!opts) { opts = {}; }
+    if (!opts) {
-  return Promise.resolve().then(function () {
+        opts = {};
-    var decoded;
+    }
+
+    var jws;
     var exp;
     var nbf;
     var active;
-    var issuers = opts.issuers || ['*'];
+    var now;
+    var then;
+    var issuers = opts.issuers || [];
+    if (opts.iss) {
+        issuers.push(opts.iss);
+    }
+    if (opts.claims && opts.claims.iss) {
+        issuers.push(opts.claims.iss);
+    }
+    if (!issuers.length) {
+        if (!(opts.jwk || opts.jwks)) {
+            throw Errors.DEVELOPER_ERROR(
+                "[keyfetch.js] Security Error: Neither of opts.issuers nor opts.iss were provided. If you would like to bypass issuer verification (i.e. for federated authn) you must explicitly set opts.issuers = ['*']. Otherwise set a value such as https://accounts.google.com/"
+            );
+        }
+    }
     var claims = opts.claims || {};
-    if (!jwt || 'string' === typeof jwt) {
+    if (!jwt || "string" === typeof jwt) {
-      try { decoded = keyfetch.jwt.decode(jwt); }
+        jws = keyfetch.jwt.decode(jwt);
-      catch (e) { throw new Error("could not parse jwt: '" + jwt + "'"); }
     } else {
-      decoded = jwt;
+        jws = jwt;
-    }
-    exp = decoded.claims.exp;
-    nbf = decoded.claims.nbf;
-
-    if (!issuers.some(isTrustedIssuer(decoded.claims.iss))) {
-      throw new Error("token was issued by an untrusted issuer: '" + decoded.claims.iss + "'");
-    }
-    // TODO verify claims also?
-    if (!Object.keys(claims).every(function (key) {
-      if (claims[key] === decoded.claims[key]) {
-        return true;
-      }
-    })) {
-      throw new Error("token did not match on one or more authorization claims: '" + Object.keys(claims) + "'");
     }
 
-    active = ((opts.exp || 0) + parseInt(exp, 10) - (Date.now()/1000) > 0);
+    if (!jws.claims.iss || !issuers.some(isTrustedIssuer(jws.claims.iss))) {
-    if (!active) {
+        if (!(opts.jwk || opts.jwks)) {
-      // expiration was on the token or, if not, such a token is not allowed
+            throw Errors.UNKNOWN_ISSUER(jws.claims.iss || "");
-      if (exp || false !== opts.exp) {
+        }
-        throw new Error("token's 'exp' has passed or could not parsed: '" + exp + "'");
-      }
     }
+    // Note claims.iss validates more strictly than opts.issuers (requires exact match)
+    var failedClaims = Object.keys(claims)
+        .filter(function (key) {
+            if (claims[key] !== jws.claims[key]) {
+                return true;
+            }
+        })
+        .map(function (key) {
+            return "jwt.claims." + key + " = " + JSON.stringify(jws.claims[key]);
+        });
+    if (failedClaims.length) {
+        throw Errors.FAILED_CLAIMS(failedClaims, Object.keys(claims));
+    }
+
+    exp = jws.claims.exp;
+    if (exp && false !== opts.exp) {
+        now = Date.now();
+        // TODO document that opts.exp can be used as leeway? Or introduce opts.leeway?
+        // fair, but not necessary
+        exp = parseInt(exp, 10);
+        if (isNaN(exp)) {
+            throw Errors.MALFORMED_EXP(JSON.stringify(jws.claims.exp));
+        }
+        then = (opts.exp || 0) + parseInt(exp, 10);
+        active = then - now / 1000 > 0;
+        // expiration was on the token or, if not, such a token is not allowed
+        if (!active) {
+            throw Errors.EXPIRED(exp);
+        }
+    }
+
+    nbf = jws.claims.nbf;
     if (nbf) {
-      active = (parseInt(nbf, 10) - (Date.now()/1000) <= 0);
+        active = parseInt(nbf, 10) - Date.now() / 1000 <= 0;
-      if (!active) {
+        if (!active) {
-        throw new Error("token's 'nbf' has not been reached or could not parsed: '" + nbf + "'");
+            throw Errors.INACTIVE(nbf);
-      }
+        }
     }
     if (opts.jwks || opts.jwk) {
-      return overrideLookup(opts.jwks || [opts.jwk]);
+        return overrideLookup(opts.jwks || [opts.jwk]);
     }
 
-    var kid = decoded.header.kid;
+    var kid = jws.header.kid;
     var iss;
     var fetcher;
     var fetchOne;
-    if (!opts.strategy || 'oidc' === opts.strategy) {
+    if (!opts.strategy || "oidc" === opts.strategy) {
-      iss = decoded.claims.iss;
+        iss = jws.claims.iss;
-      fetcher = keyfetch.oidcJwks;
+        fetcher = keyfetch.oidcJwks;
-      fetchOne = keyfetch.oidcJwk;
+        fetchOne = keyfetch.oidcJwk;
-    } else if ('auth0' === opts.strategy || 'well-known' === opts.strategy) {
+    } else if ("auth0" === opts.strategy || "well-known" === opts.strategy) {
-      iss = decoded.claims.iss;
+        iss = jws.claims.iss;
-      fetcher = keyfetch.wellKnownJwks;
+        fetcher = keyfetch.wellKnownJwks;
-      fetchOne = keyfetch.wellKnownJwk;
+        fetchOne = keyfetch.wellKnownJwk;
     } else {
-      iss = opts.strategy;
+        iss = opts.strategy;
-      fetcher = keyfetch.jwks;
+        fetcher = keyfetch.jwks;
-      fetchOne = keyfetch.jwk;
+        fetchOne = keyfetch.jwk;
     }
 
-    var p;
     if (kid) {
-      p = fetchOne(kid, iss).then(verifyOne); //.catch(fetchAny);
+        return fetchOne(kid, iss).then(verifyOne); //.catch(fetchAny);
-    } else {
-      p = fetcher(iss).then(verifyAny);
     }
-    return p;
+    return fetcher(iss).then(verifyAny);
 
     function verifyOne(hit) {
-      if (true === keyfetch.jws.verify(decoded, hit)) {
+        if (true === keyfetch.jws.verify(jws, hit)) {
-        return decoded;
+            return jws;
-      }
+        }
-      throw new Error('token signature verification was unsuccessful');
+        throw Errors.BAD_SIGNATURE(jws.protected + "." + jws.payload + "." + jws.signature);
     }
 
     function verifyAny(hits) {
-      if (hits.some(function (hit) {
+        if (
-        if (kid) {
+            hits.some(function (hit) {
-          if (kid !== hit.jwk.kid && kid !== hit.thumbprint) { return; }
+                if (kid) {
-          if (true === keyfetch.jws.verify(decoded, hit)) { return true; }
+                    if (kid !== hit.jwk.kid && kid !== hit.thumbprint) {
-          throw new Error('token signature verification was unsuccessful');
+                        return;
-        } else {
+                    }
-          if (true === keyfetch.jws.verify(decoded, hit)) { return true; }
+                    if (true === keyfetch.jws.verify(jws, hit)) {
+                        return true;
+                    }
+                    throw Errors.BAD_SIGNATURE();
+                }
+                if (true === keyfetch.jws.verify(jws, hit)) {
+                    return true;
+                }
+            })
+        ) {
+            return jws;
         }
-      })) {
+        throw Errors.JWK_NOT_FOUND_OLD(kid);
-        return decoded;
-      }
-      throw new Error("Retrieved a list of keys, but none of them matched the 'kid' (key id) of the token.");
     }
 
     function overrideLookup(jwks) {
-      return Promise.all(jwks.map(function (jwk) {
+        return Promise.all(
-        var Keypairs = jwk.x ? Eckles : Rasha;
+            jwks.map(async function (jwk) {
-        return Keypairs.export({ jwk: jwk }).then(function (pem) {
+                var Keypairs = jwk.x ? Eckles : Rasha;
-          return Keypairs.thumbprint({ jwk: jwk }).then(function (thumb) {
+                var pem = await Keypairs.export({ jwk: jwk });
-            return { jwk: jwk, pem: pem, thumbprint: thumb };
+                var thumb = await Keypairs.thumbprint({ jwk: jwk });
-          });
+                return { jwk: jwk, pem: pem, thumbprint: thumb };
-        });
+            })
-      })).then(verifyAny);
+        ).then(verifyAny);
     }
-  });
 };
 keyfetch.jws = {};
 keyfetch.jws.verify = function (jws, pub) {
-  var alg = 'SHA' + jws.header.alg.replace(/[^\d]+/i, '');
+    var alg = "SHA" + jws.header.alg.replace(/[^\d]+/i, "");
-  var sig = ecdsaAsn1SigToJwtSig(jws.header, jws.signature);
+    var sig = ecdsaJoseSigToAsn1Sig(jws.header, jws.signature);
-  return require('crypto')
+    return require("crypto")
-    .createVerify(alg)
+        .createVerify(alg)
-    .update(jws.protected + '.' + jws.payload)
+        .update(jws.protected + "." + jws.payload)
-    .verify(pub.pem, sig, 'base64')
+        .verify(pub.pem, sig, "base64");
-  ;
 };
 
 // old, gotta make sure nothing else uses this
 keyfetch._decode = function (jwt) {
-  var obj = keyfetch.jwt.decode(jwt);
+    var obj = keyfetch.jwt.decode(jwt);
-  return { header: obj.header, payload: obj.claims, signature: obj.signature };
+    return { header: obj.header, payload: obj.claims, signature: obj.signature };
-};
+};
-keyfetch.verify = function (opts) {
+keyfetch.verify = async function (opts) {
-  var jwt = opts.jwt;
+    var jwt = opts.jwt;
-  return keyfetch.jwt.verify(jwt, opts).then(function (obj) {
+    var obj = await keyfetch.jwt.verify(jwt, opts);
     return { header: obj.header, payload: obj.claims, signature: obj.signature };
-  });
 };
 
-function ecdsaAsn1SigToJwtSig(header, b64sig) {
+function ecdsaJoseSigToAsn1Sig(header, b64sig) {
-  // ECDSA JWT signatures differ from "normal" ECDSA signatures
+    // ECDSA JWT signatures differ from "normal" ECDSA signatures
-  // https://tools.ietf.org/html/rfc7518#section-3.4
+    // https://tools.ietf.org/html/rfc7518#section-3.4
-  if (!/^ES/i.test(header.alg)) { return b64sig; }
+    if (!/^ES/i.test(header.alg)) {
+        return b64sig;
+    }
 
-  var bufsig = Buffer.from(b64sig, 'base64');
+    var bufsig = Buffer.from(b64sig, "base64");
-  var hlen = bufsig.byteLength / 2; // should be even
+    var hlen = bufsig.byteLength / 2; // should be even
-  var r = bufsig.slice(0, hlen);
+    var r = bufsig.slice(0, hlen);
-  var s = bufsig.slice(hlen);
+    var s = bufsig.slice(hlen);
-  // unpad positive ints less than 32 bytes wide
+    // unpad positive ints less than 32 bytes wide
-  while (!r[0]) { r = r.slice(1); }
+    while (!r[0]) {
-  while (!s[0]) { s = s.slice(1); }
+        r = r.slice(1);
-  // pad (or re-pad) ambiguously non-negative BigInts to 33 bytes wide
+    }
-  if (0x80 & r[0]) { r = Buffer.concat([Buffer.from([0]), r]); }
+    while (!s[0]) {
-  if (0x80 & s[0]) { s = Buffer.concat([Buffer.from([0]), s]); }
+        s = s.slice(1);
+    }
+    // pad (or re-pad) ambiguously non-negative BigInts to 33 bytes wide
+    if (0x80 & r[0]) {
+        r = Buffer.concat([Buffer.from([0]), r]);
+    }
+    if (0x80 & s[0]) {
+        s = Buffer.concat([Buffer.from([0]), s]);
+    }
 
-  var len = 2 + r.byteLength + 2 + s.byteLength;
+    var len = 2 + r.byteLength + 2 + s.byteLength;
-  var head = [0x30];
+    var head = [0x30];
-  // hard code 0x80 + 1 because it won't be longer than
+    // hard code 0x80 + 1 because it won't be longer than
-  // two SHA512 plus two pad bytes (130 bytes <= 256)
+    // two SHA512 plus two pad bytes (130 bytes <= 256)
-  if (len >= 0x80) { head.push(0x81); }
+    if (len >= 0x80) {
-  head.push(len);
+        head.push(0x81);
+    }
+    head.push(len);
 
-  var buf = Buffer.concat([
+    var buf = Buffer.concat([
-    Buffer.from(head)
+        Buffer.from(head),
-  , Buffer.from([0x02, r.byteLength]), r
+        Buffer.from([0x02, r.byteLength]),
-  , Buffer.from([0x02, s.byteLength]), s
+        r,
-  ]);
+        Buffer.from([0x02, s.byteLength]),
+        s
+    ]);
 
-  return buf.toString('base64')
+    return buf.toString("base64").replace(/-/g, "+").replace(/_/g, "/").replace(/=/g, "");
-    .replace(/-/g, '+')
-    .replace(/_/g, '/')
-    .replace(/=/g, '')
-  ;
 }
 
 function isTrustedIssuer(issuer) {
-  return function (trusted) {
+    return function (trusted) {
-    if ('*' === trusted) { return true; }
+        if ("*" === trusted) {
-    // TODO account for '*.example.com'
+            return true;
-    trusted = (/^http(s?):\/\//.test(trusted) ? trusted : ('https://' + trusted));
+        }
-    return issuer.replace(/\/$/, '') === trusted.replace(/\/$/, '') && trusted;
+        // TODO account for '*.example.com'
-  };
+        trusted = /^http(s?):\/\//.test(trusted) ? trusted : "https://" + trusted;
+        return issuer.replace(/\/$/, "") === trusted.replace(/\/$/, "") && trusted;
+    };
 }

lib/errors.js

@@ -0,0 +1,270 @@
+"use strict";
+
+// Possible User Errors
+
+/**
+ * @typedef AuthError
+ * @property {string} message
+ * @property {number} status
+ * @property {string} code
+ * @property {any} [details]
+ */
+
+/**
+ * @param {string} msg
+ * @param {{
+ *   status: number,
+ *   code: string,
+ *   details?: any,
+ * }} opts
+ * @returns {AuthError}
+ */
+function create(old, msg, code, status, details) {
+    /** @type AuthError */
+    //@ts-ignore
+    let err = new Error(msg);
+    err.message = msg;
+    err._old_message = old;
+    err.code = code;
+    err.status = status;
+    if (details) {
+        err.details = details;
+    }
+    err.source = "keyfetch";
+    err.toJSON = toJSON;
+    err.toString = toString;
+    return err;
+}
+
+function toJSON() {
+    /*jshint validthis:true*/
+    return {
+        message: this.message,
+        status: this.status,
+        code: this.code,
+        details: this.details
+    };
+}
+function toString() {
+    /*jshint validthis:true*/
+    return this.stack + "\n" + JSON.stringify(this);
+}
+
+// DEVELOPER_ERROR - a good token won't make a difference
+var E_DEVELOPER = "DEVELOPER_ERROR";
+
+// BAD_GATEWAY - there may be a temporary error fetching the public or or whatever
+var E_BAD_GATEWAY = "BAD_GATEWAY";
+
+// MALFORMED_JWT - the token could not be verified - not parsable, missing claims, etc
+var E_MALFORMED = "MALFORMED_JWT";
+
+// INVALID_JWT - the token's properties don't meet requirements - iss, claims, sig, exp
+var E_INVALID = "INVALID_JWT";
+
+module.exports = {
+    //
+    // DEVELOPER_ERROR (dev / server)
+    //
+
+    /**
+     * @param {string} msg
+     * @returns {AuthError}
+     */
+    DEVELOPER_ERROR: function (old, msg, details) {
+        return create(old, msg || old, E_DEVELOPER, 500, details);
+    },
+    BAD_GATEWAY: function (err) {
+        var msg =
+            "The auth token could not be verified because our server encountered a network error (or a bad gateway) when connecting to its issuing server.";
+        var details = [];
+        if (err.message) {
+            details.push("error.message = " + err.message);
+        }
+        if (err.response && err.response.statusCode) {
+            details.push("response.statusCode = " + err.response.statusCode);
+        }
+        return create(msg, msg, E_BAD_GATEWAY, 502, details);
+    },
+
+    //
+    // MALFORMED_TOKEN (dev / client)
+    //
+
+    /**
+     * @param {string} iss
+     * @returns {AuthError}
+     */
+    INSECURE_ISSUER: function (iss) {
+        var old =
+            "'" + iss + "' is NOT secure. Set env 'KEYFETCH_ALLOW_INSECURE_HTTP=true' to allow for testing. (iss)";
+        var details = [
+            "jwt.claims.iss = " + JSON.stringify(iss),
+            "DEBUG: Set ENV 'KEYFETCH_ALLOW_INSECURE_HTTP=true' to allow insecure issuers (for testing)."
+        ];
+        var msg =
+            'The auth token could not be verified because our server could connect to its issuing server ("iss") securely.';
+        return create(old, msg, E_MALFORMED, 400, details);
+    },
+    /**
+     * @param {string} jwt
+     * @returns {AuthError}
+     */
+    PARSE_ERROR: function (jwt) {
+        var old = "could not parse jwt: '" + jwt + "'";
+        var msg = "The auth token could not be verified because it is malformed.";
+        var details = ["jwt = " + JSON.stringify(jwt)];
+        return create(old, msg, E_MALFORMED, 400, details);
+    },
+    /**
+     * @param {string} iss
+     * @returns {AuthError}
+     */
+    NO_ISSUER: function (iss) {
+        var old = "'iss' is not defined";
+        var msg = 'The auth token could not be verified because it doesn\'t specify an issuer ("iss").';
+        var details = ["jwt.claims.iss = " + JSON.stringify(iss)];
+        return create(old, msg, E_MALFORMED, 400, details);
+    },
+
+    /**
+     * @param {string} iss
+     * @returns {AuthError}
+     */
+    MALFORMED_EXP: function (exp) {
+        var old = "token's 'exp' has passed or could not parsed: '" + exp + "'";
+        var msg = 'The auth token could not be verified because it\'s expiration date ("exp") could not be read';
+        var details = ["jwt.claims.exp = " + JSON.stringify(exp)];
+        return create(old, msg, E_MALFORMED, 400, details);
+    },
+
+    //
+    // INVALID_TOKEN (dev / client)
+    //
+
+    /**
+     * @param {number} exp
+     * @returns {AuthError}
+     */
+    EXPIRED: function (exp) {
+        var old = "token's 'exp' has passed or could not parsed: '" + exp + "'";
+        // var msg = "The auth token did not pass verification because it is expired.not properly signed.";
+        var msg = "The auth token is expired. To try again, go to the main page and sign in.";
+        var details = ["jwt.claims.exp = " + JSON.stringify(exp)];
+        return create(old, msg, E_INVALID, 401, details);
+    },
+    /**
+     * @param {number} nbf
+     * @returns {AuthError}
+     */
+    INACTIVE: function (nbf) {
+        var old = "token's 'nbf' has not been reached or could not parsed: '" + nbf + "'";
+        var msg = "The auth token isn't valid yet. It's activation date (\"nbf\") is in the future.";
+        var details = ["jwt.claims.nbf = " + JSON.stringify(nbf)];
+        return create(old, msg, E_INVALID, 401, details);
+    },
+    /** @returns {AuthError} */
+    BAD_SIGNATURE: function (jwt) {
+        var old = "token signature verification was unsuccessful";
+        var msg = "The auth token did not pass verification because it is not properly signed.";
+        var details = ["jwt = " + JSON.stringify(jwt)];
+        return create(old, msg, E_INVALID, 401, details);
+    },
+    /**
+     * @param {string} kid
+     * @returns {AuthError}
+     */
+    JWK_NOT_FOUND_OLD: function (kid) {
+        var old = "Retrieved a list of keys, but none of them matched the 'kid' (key id) of the token.";
+        var msg =
+            'The auth token did not pass verification because our server couldn\'t find a mutually trusted verification key ("jwk").';
+        var details = ["jws.header.kid = " + JSON.stringify(kid)];
+        return create(old, msg, E_INVALID, 401, details);
+    },
+    /**
+     * @param {string} id
+     * @returns {AuthError}
+     */
+    JWK_NOT_FOUND: function (id) {
+        // TODO Distinguish between when it's a kid vs thumbprint.
+        var old = "No JWK found by kid or thumbprint '" + id + "'";
+        var msg =
+            'The auth token did not pass verification because our server couldn\'t find a mutually trusted verification key ("jwk").';
+        var details = ["jws.header.kid = " + JSON.stringify(id)];
+        return create(old, msg, E_INVALID, 401, details);
+    },
+    /** @returns {AuthError} */
+    NO_JWKWS_URI: function (url) {
+        var old = "Failed to retrieve openid configuration";
+        var msg =
+            'The auth token did not pass verification because its issuing server did not list any verification keys ("jwks").';
+        var details = ["OpenID Provider Configuration: " + JSON.stringify(url)];
+        return create(old, msg, E_INVALID, 401, details);
+    },
+    /**
+     * @param {string} iss
+     * @returns {AuthError}
+     */
+    UNKNOWN_ISSUER: function (iss) {
+        var old = "token was issued by an untrusted issuer: '" + iss + "'";
+        var msg = "The auth token did not pass verification because it wasn't issued by a server that we trust.";
+        var details = ["jwt.claims.iss = " + JSON.stringify(iss)];
+        return create(old, msg, E_INVALID, 401, details);
+    },
+    /**
+     * @param {Array<string>} details
+     * @returns {AuthError}
+     */
+    FAILED_CLAIMS: function (details, claimNames) {
+        var old = "token did not match on one or more authorization claims: '" + claimNames + "'";
+        var msg =
+            'The auth token did not pass verification because it failed some of the verification criteria ("claims").';
+        return create(old, msg, E_INVALID, 401, details);
+    }
+};
+var Errors = module.exports;
+
+// for README
+if (require.main === module) {
+    let maxWidth = 54;
+    let header = ["Hint", "Code", "Status", "Message (truncated)"];
+    let widths = header.map(function (v) {
+        return Math.min(maxWidth, String(v).length);
+    });
+    let rows = [];
+    Object.keys(module.exports).forEach(function (k) {
+        //@ts-ignore
+        var E = module.exports[k];
+        var e = E("test");
+        var code = e.code;
+        var msg = e.message;
+        var hint = k.toLowerCase().replace(/_/g, " ");
+        widths[0] = Math.max(widths[0], String(hint).length);
+        widths[1] = Math.max(widths[1], String(code).length);
+        widths[2] = Math.max(widths[2], String(e.status).length);
+        widths[3] = Math.min(maxWidth, Math.max(widths[3], String(msg).length));
+        rows.push([hint, code, e.status, msg]);
+    });
+    rows.forEach(function (cols, i) {
+        let cells = cols.map(function (col, i) {
+            if (col.length > maxWidth) {
+                col = col.slice(0, maxWidth - 3);
+                col += "...";
+            }
+            return String(col).padEnd(widths[i], " ");
+        });
+        let out = `| ${cells[0]} | ${cells[1]} | ${cells[2]} | ${cells[3].slice(0, widths[3])} |`;
+        //out = out.replace(/\| /g, " ").replace(/\|/g, "");
+        console.info(out);
+        if (i === 0) {
+            cells = cols.map(function (col, i) {
+                return "-".padEnd(widths[i], "-");
+            });
+            console.info(`| ${cells[0]} | ${cells[1]} | ${cells[2]} | ${cells[3]} |`);
+        }
+    });
+    console.log();
+    console.log(Errors.MALFORMED_EXP());
+    console.log();
+    console.log(JSON.stringify(Errors.MALFORMED_EXP(), null, 2));
+}

package-lock.json

@@ -1,23 +1,82 @@
 {
-  "name": "keyfetch",
+    "name": "keyfetch",
-  "version": "1.1.8",
+    "version": "3.0.2",
-  "lockfileVersion": 1,
+    "lockfileVersion": 2,
-  "requires": true,
+    "requires": true,
-  "dependencies": {
+    "packages": {
-    "@coolaj86/urequest": {
+        "": {
-      "version": "1.3.7",
+            "name": "keyfetch",
-      "resolved": "https://registry.npmjs.org/@coolaj86/urequest/-/urequest-1.3.7.tgz",
+            "version": "3.0.2",
-      "integrity": "sha512-PPrVYra9aWvZjSCKl/x1pJ9ZpXda1652oJrPBYy5rQumJJMkmTBN3ux+sK2xAUwVvv2wnewDlaQaHLxLwSHnIA=="
+            "license": "MPL-2.0",
+            "dependencies": {
+                "@root/request": "^1.8.0",
+                "eckles": "^1.4.1",
+                "rasha": "^1.2.4"
+            },
+            "devDependencies": {
+                "keypairs": "^1.2.14"
+            }
+        },
+        "node_modules/@root/request": {
+            "version": "1.8.0",
+            "resolved": "https://registry.npmjs.org/@root/request/-/request-1.8.0.tgz",
+            "integrity": "sha512-HufCvoTwqR30OyKSjwg28W5QCUpypSJZpOYcJbC9PME5kI6cOYsccYs/6bXfsuEoarz8+YwBDrsuM1UdBMxMLw=="
+        },
+        "node_modules/eckles": {
+            "version": "1.4.1",
+            "resolved": "https://registry.npmjs.org/eckles/-/eckles-1.4.1.tgz",
+            "integrity": "sha512-auWyk/k8oSkVHaD4RxkPadKsLUcIwKgr/h8F7UZEueFDBO7BsE4y+H6IMUDbfqKIFPg/9MxV6KcBdJCmVVcxSA==",
+            "bin": {
+                "eckles": "bin/eckles.js"
+            }
+        },
+        "node_modules/keypairs": {
+            "version": "1.2.14",
+            "resolved": "https://registry.npmjs.org/keypairs/-/keypairs-1.2.14.tgz",
+            "integrity": "sha512-ZoZfZMygyB0QcjSlz7Rh6wT2CJasYEHBPETtmHZEfxuJd7bnsOG5AdtPZqHZBT+hoHvuWCp/4y8VmvTvH0Y9uA==",
+            "dev": true,
+            "dependencies": {
+                "eckles": "^1.4.1",
+                "rasha": "^1.2.4"
+            },
+            "bin": {
+                "keypairs-install": "bin/keypairs.js"
+            }
+        },
+        "node_modules/rasha": {
+            "version": "1.2.4",
+            "resolved": "https://registry.npmjs.org/rasha/-/rasha-1.2.4.tgz",
+            "integrity": "sha512-GsIwKv+hYSumJyK9wkTDaERLwvWaGYh1WuI7JMTBISfYt13TkKFU/HFzlY4n72p8VfXZRUYm0AqaYhkZVxOC3Q==",
+            "bin": {
+                "rasha": "bin/rasha.js"
+            }
+        }
     },
-    "eckles": {
+    "dependencies": {
-      "version": "1.4.1",
+        "@root/request": {
-      "resolved": "https://registry.npmjs.org/eckles/-/eckles-1.4.1.tgz",
+            "version": "1.8.0",
-      "integrity": "sha512-auWyk/k8oSkVHaD4RxkPadKsLUcIwKgr/h8F7UZEueFDBO7BsE4y+H6IMUDbfqKIFPg/9MxV6KcBdJCmVVcxSA=="
+            "resolved": "https://registry.npmjs.org/@root/request/-/request-1.8.0.tgz",
-    },
+            "integrity": "sha512-HufCvoTwqR30OyKSjwg28W5QCUpypSJZpOYcJbC9PME5kI6cOYsccYs/6bXfsuEoarz8+YwBDrsuM1UdBMxMLw=="
-    "rasha": {
+        },
-      "version": "1.2.4",
+        "eckles": {
-      "resolved": "https://registry.npmjs.org/rasha/-/rasha-1.2.4.tgz",
+            "version": "1.4.1",
-      "integrity": "sha512-GsIwKv+hYSumJyK9wkTDaERLwvWaGYh1WuI7JMTBISfYt13TkKFU/HFzlY4n72p8VfXZRUYm0AqaYhkZVxOC3Q=="
+            "resolved": "https://registry.npmjs.org/eckles/-/eckles-1.4.1.tgz",
+            "integrity": "sha512-auWyk/k8oSkVHaD4RxkPadKsLUcIwKgr/h8F7UZEueFDBO7BsE4y+H6IMUDbfqKIFPg/9MxV6KcBdJCmVVcxSA=="
+        },
+        "keypairs": {
+            "version": "1.2.14",
+            "resolved": "https://registry.npmjs.org/keypairs/-/keypairs-1.2.14.tgz",
+            "integrity": "sha512-ZoZfZMygyB0QcjSlz7Rh6wT2CJasYEHBPETtmHZEfxuJd7bnsOG5AdtPZqHZBT+hoHvuWCp/4y8VmvTvH0Y9uA==",
+            "dev": true,
+            "requires": {
+                "eckles": "^1.4.1",
+                "rasha": "^1.2.4"
+            }
+        },
+        "rasha": {
+            "version": "1.2.4",
+            "resolved": "https://registry.npmjs.org/rasha/-/rasha-1.2.4.tgz",
+            "integrity": "sha512-GsIwKv+hYSumJyK9wkTDaERLwvWaGYh1WuI7JMTBISfYt13TkKFU/HFzlY4n72p8VfXZRUYm0AqaYhkZVxOC3Q=="
+        }
     }
-  }
 }

package.json

@@ -1,36 +1,39 @@
 {
-  "name": "keyfetch",
+    "name": "keyfetch",
-  "version": "1.2.1",
+    "version": "3.0.2",
-  "description": "Lightweight support for fetching JWKs.",
+    "description": "Lightweight support for fetching JWKs.",
-  "homepage": "https://git.coolaj86.com/coolaj86/keyfetch.js",
+    "homepage": "https://git.rootprojects.org/root/keyfetch.js",
-  "main": "keyfetch.js",
+    "main": "keyfetch.js",
-  "files": [],
+    "files": [
-  "dependencies": {
+        "lib"
-    "@coolaj86/urequest": "^1.3.7",
+    ],
-    "eckles": "^1.4.1",
+    "dependencies": {
-    "rasha": "^1.2.4"
+        "@root/request": "^1.8.0",
-  },
+        "eckles": "^1.4.1",
-  "devDependencies": {},
+        "rasha": "^1.2.4"
-  "scripts": {
+    },
-    "test": "node keyfetch-test.js"
+    "devDependencies": {
-  },
+        "keypairs": "^1.2.14"
-  "repository": {
+    },
-    "type": "git",
+    "scripts": {
-    "url": "https://git.coolaj86.com/coolaj86/keyfetch.js.git"
+        "test": "node keyfetch-test.js"
-  },
+    },
-  "keywords": [
+    "repository": {
-    "jwks",
+        "type": "git",
-    "jwk",
+        "url": "https://git.rootprojects.org/root/keyfetch.js.git"
-    "jwt",
+    },
-    "auth0",
+    "keywords": [
-    "pem",
+        "jwks",
-    "RSA",
+        "jwk",
-    "EC",
+        "jwt",
-    "ECDSA",
+        "auth0",
-    "OIDC",
+        "pem",
-    "well-known"
+        "RSA",
-  ],
+        "EC",
-  "author": "AJ ONeal <solderjs@gmail.com> (https://coolaj86.com/)",
+        "ECDSA",
-  "license": "MPL-2.0"
+        "OIDC",
+        "well-known"
+    ],
+    "author": "AJ ONeal <coolaj86@gmail.com> (https://coolaj86.com/)",
+    "license": "MPL-2.0"
 }
-