Initial commit

node_modules/jose/lib/jwa/aes_gcm.js

@@ -0,0 +1,55 @@
+const { createCipheriv, createDecipheriv, getCiphers } = require('crypto')
+
+const { KEYOBJECT } = require('../help/consts')
+const { JWEInvalid, JWEDecryptionFailed } = require('../errors')
+const { asInput } = require('../help/key_object')
+
+const checkInput = function (size, iv, tag) {
+  if (iv.length !== 12) {
+    throw new JWEInvalid('invalid iv')
+  }
+  if (arguments.length === 3) {
+    if (tag.length !== 16) {
+      throw new JWEInvalid('invalid tag')
+    }
+  }
+}
+
+const encrypt = (size, { [KEYOBJECT]: keyObject }, cleartext, { iv, aad = Buffer.alloc(0) }) => {
+  const key = asInput(keyObject, false)
+  checkInput(size, iv)
+
+  const cipher = createCipheriv(`aes-${size}-gcm`, key, iv, { authTagLength: 16 })
+  cipher.setAAD(aad)
+
+  const ciphertext = Buffer.concat([cipher.update(cleartext), cipher.final()])
+  const tag = cipher.getAuthTag()
+
+  return { ciphertext, tag }
+}
+
+const decrypt = (size, { [KEYOBJECT]: keyObject }, ciphertext, { iv, tag = Buffer.alloc(0), aad = Buffer.alloc(0) }) => {
+  const key = asInput(keyObject, false)
+  checkInput(size, iv, tag)
+
+  try {
+    const cipher = createDecipheriv(`aes-${size}-gcm`, key, iv, { authTagLength: 16 })
+    cipher.setAuthTag(tag)
+    cipher.setAAD(aad)
+
+    return Buffer.concat([cipher.update(ciphertext), cipher.final()])
+  } catch (err) {
+    throw new JWEDecryptionFailed()
+  }
+}
+
+module.exports = (JWA, JWK) => {
+  ['A128GCM', 'A192GCM', 'A256GCM'].forEach((jwaAlg) => {
+    const size = parseInt(jwaAlg.substr(1, 3), 10)
+    if (getCiphers().includes(`aes-${size}-gcm`)) {
+      JWA.encrypt.set(jwaAlg, encrypt.bind(undefined, size))
+      JWA.decrypt.set(jwaAlg, decrypt.bind(undefined, size))
+      JWK.oct.encrypt[jwaAlg] = JWK.oct.decrypt[jwaAlg] = key => (key.use === 'enc' || key.use === undefined) && key.length === size
+    }
+  })
+}