decrypt notes

src/utils/crypto.ts

@@ -0,0 +1,15 @@
+import CryptoJS from 'crypto-js'
+
+const encryptionPrefix = 'contexted|'
+const salt = 'salt'
+
+export const calculateClientKey = (passphrase: string): ClientKey => {
+  return CryptoJS.PBKDF2(passphrase, salt, { keySize: 256 / 32 }).toString()
+}
+
+export const decrypt = (encryptedMessage: string, key: string): string => {
+  const decryptedMessage = CryptoJS.AES.decrypt(encryptedMessage, key).toString(CryptoJS.enc.Utf8)
+  if (!decryptedMessage.startsWith(encryptionPrefix))
+    throw new Error("Message doesn't have valid encryption")
+  return decryptedMessage.substring(encryptionPrefix.length)
+}