Merge 1ccf281 into 25dccaa

.editorconfig

@@ -0,0 +1,8 @@
+# EditorConfig is awesome: http://EditorConfig.org
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+insert_final_newline = true

lib/common.js

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+/* jshint esversion: 6 */
+/* jslint node: true */
+'use strict';
+
+const HeaderParameters = {
+  'alg': 1,
+  'crit': 2,
+  'content_type': 3,
+  'kid': 4,
+  'IV': 5,
+  'Partial_IV': 6,
+  'counter_signature': 7
+};
+
+exports.TranslateHeaders = function (header) {
+  const result = new Map();
+  for (var param in header) {
+    if (!HeaderParameters[param]) {
+      throw new Error('Unknown parameter, ' + param);
+    }
+    result.set(HeaderParameters[param], header[param]);
+  }
+  return result;
+};
+
+exports.HeaderParameters = HeaderParameters;

lib/index.js

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+/* jshint esversion: 6 */
+/* jslint node: true */
+'use strict';
+
+exports.common = require('./common');
+exports.mac = require('./mac');
+exports.sign = require('./sign');

lib/mac.js

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+/* jshint esversion: 6 */
+/* jslint node: true */
+'use strict';
+
+const cbor = require('cbor');
+const crypto = require('crypto');
+const Promise = require('any-promise');
+const common = require('./common');
+
+const AlgTags = {
+  // "SHA-256_64":4,
+  // TODO implement truncation
+  'SHA-256': 5,
+  'SHA-384': 6,
+  'SHA-512': 7
+};
+
+// TODO content type map?
+
+function doMac (context, hProtected, externalAAD, payload, alg, key) {
+  return new Promise((resolve, reject) => {
+    const MACstructure = [
+      context, // "MAC0", // context
+      hProtected, // protected
+      externalAAD, // bstr,
+      payload // bstr
+    ];
+    const ToBeMaced = cbor.encode(MACstructure);
+
+    const hmac = crypto.createHmac(alg, key);// TODO make algorithm dynamic
+    hmac.end(ToBeMaced, function () {
+      resolve(hmac.read());
+    });
+  });
+}
+
+exports.create = function (protIn, unprotected, payload, key, externalAAD) {
+  externalAAD = externalAAD || null; // TODO default to zero length binary string
+  const hProtected = common.TranslateHeaders(protIn);
+
+  if (protIn.alg && AlgTags[protIn.alg]) {
+    hProtected.set(common.HeaderParameters.alg, AlgTags[protIn.alg]);
+  } else {
+    // TODO return better error
+    throw new Error('Alg is mandatory and must have a known value');
+  }
+  // TODO handle empty map -> convert to zero length bstr
+  // TODO check crit headers
+  return doMac('MAC0', hProtected, externalAAD, payload, 'sha256', key)
+  .then((tag) => {
+    return cbor.encode([hProtected, unprotected, payload, tag]);
+  });
+};
+
+exports.read = function (data, key, externalAAD) {
+  externalAAD = externalAAD || null;
+
+  return cbor.decodeFirst(data)
+  .then((obj) => {
+    const hProtected = obj[0];
+    // const unprotected = obj[1];
+    const payload = obj[2];
+    const tag = obj[3];
+
+    // TODO validate protected header
+    return doMac('MAC0', hProtected, externalAAD, payload, 'sha256', key)
+    .then((calcTag) => {
+      // TODO: why was this here?  Make sure it's not needed anymore and
+      // delete, along with unprotected above.
+      // const encoded = cbor.encode([hProtected, unprotected, payload, tag]);
+
+      if (tag.toString('hex') !== calcTag.toString('hex')) {
+        throw new Error('Tag mismatch');
+      }
+
+      return payload;
+    });
+  });
+};

lib/sign.js

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+/* jshint esversion: 6 */
+/* jslint node: true */
+'use strict';
+
+const cbor = require('cbor');
+const WebCrypto = require('node-webcrypto-ossl');
+const crypto = new WebCrypto();
+const common = require('./common');
+
+function toArrayBuffer (buf) {
+  return Uint8Array.from(buf).buffer;
+}
+
+function toBuffer (ab) {
+  return Buffer.from(ab);
+}
+
+exports.create = function (Headers, payload, key, externalAAD) {
+  const protHeader = common.TranslateHeaders(Headers.prot);
+  const cborProtHeader = cbor.encode(protHeader); // TODO handle empty header?
+  const SigStructure = [
+    'Signature1',
+    cborProtHeader,
+    externalAAD,
+    payload
+  ];
+
+  const ToBeSigned = toArrayBuffer(cbor.encode(SigStructure));
+
+  // TODO read alg and act on it
+  return crypto.subtle.sign({
+    name: 'ECDSA',
+    hash: {name: 'SHA-256'}
+  },
+    key.privateKey,
+    ToBeSigned)
+    .then((signature) => {
+      return cbor.encode([
+        cborProtHeader,
+        Headers.unprot,
+        payload,
+        toBuffer(signature)
+      ]);
+    });
+};
+
+/*
+return crypto.subtle.verify({
+  name: "ECDSA",
+  hash: {name: "SHA-256"}},
+  publicKey, //from generateKey or importKey above
+  signature, //ArrayBuffer of the signature
+  data) //ArrayBuffer of the data
+  */