Add node modules and compiled JavaScript from main (#54)

Co-authored-by: Oliver King <oking3@uncc.edu>

node_modules/jose/lib/jwa/aes_cbc_hmac_sha2.js

@@ -0,0 +1,74 @@
+const { createCipheriv, createDecipheriv, getCiphers } = require('crypto')
+
+const uint64be = require('../help/uint64be')
+const timingSafeEqual = require('../help/timing_safe_equal')
+const { KEYOBJECT } = require('../help/consts')
+const { JWEInvalid, JWEDecryptionFailed } = require('../errors')
+
+const checkInput = function (size, iv, tag) {
+  if (iv.length !== 16) {
+    throw new JWEInvalid('invalid iv')
+  }
+  if (arguments.length === 3) {
+    if (tag.length !== size / 8) {
+      throw new JWEInvalid('invalid tag')
+    }
+  }
+}
+
+const encrypt = (size, sign, { [KEYOBJECT]: keyObject }, cleartext, { iv, aad = Buffer.alloc(0) }) => {
+  const key = keyObject.export()
+  checkInput(size, iv)
+
+  const keySize = size / 8
+  const encKey = key.slice(keySize)
+  const cipher = createCipheriv(`aes-${size}-cbc`, encKey, iv)
+  const ciphertext = Buffer.concat([cipher.update(cleartext), cipher.final()])
+  const macData = Buffer.concat([aad, iv, ciphertext, uint64be(aad.length * 8)])
+
+  const macKey = key.slice(0, keySize)
+  const tag = sign({ [KEYOBJECT]: macKey }, macData).slice(0, keySize)
+
+  return { ciphertext, tag }
+}
+
+const decrypt = (size, sign, { [KEYOBJECT]: keyObject }, ciphertext, { iv, tag = Buffer.alloc(0), aad = Buffer.alloc(0) }) => {
+  checkInput(size, iv, tag)
+
+  const keySize = size / 8
+  const key = keyObject.export()
+  const encKey = key.slice(keySize)
+  const macKey = key.slice(0, keySize)
+
+  const macData = Buffer.concat([aad, iv, ciphertext, uint64be(aad.length * 8)])
+  const expectedTag = sign({ [KEYOBJECT]: macKey }, macData, tag).slice(0, keySize)
+  const macCheckPassed = timingSafeEqual(tag, expectedTag)
+
+  if (!macCheckPassed) {
+    throw new JWEDecryptionFailed()
+  }
+
+  let cleartext
+  try {
+    const cipher = createDecipheriv(`aes-${size}-cbc`, encKey, iv)
+    cleartext = Buffer.concat([cipher.update(ciphertext), cipher.final()])
+  } catch (err) {}
+
+  if (!cleartext) {
+    throw new JWEDecryptionFailed()
+  }
+
+  return cleartext
+}
+
+module.exports = (JWA, JWK) => {
+  ['A128CBC-HS256', 'A192CBC-HS384', 'A256CBC-HS512'].forEach((jwaAlg) => {
+    const size = parseInt(jwaAlg.substr(1, 3), 10)
+    const sign = JWA.sign.get(`HS${size * 2}`)
+    if (getCiphers().includes(`aes-${size}-cbc`)) {
+      JWA.encrypt.set(jwaAlg, encrypt.bind(undefined, size, sign))
+      JWA.decrypt.set(jwaAlg, decrypt.bind(undefined, size, sign))
+      JWK.oct.encrypt[jwaAlg] = JWK.oct.decrypt[jwaAlg] = key => (key.use === 'enc' || key.use === undefined) && key.length / 2 === size
+    }
+  })
+}