Cloud service for private notes – Gap between convenience and confidentiality

Keeping private notes and thoughts confidential while still having them accessible from multiple devices is a challenge in the digital age. Cloud-based note services promise anywhere access along with strong encryption to keep your notes secure, aiming to bridge the gap between convenience and confidentiality.

Rise of encrypted cloud notes

As mobile devices proliferated over the last decade, access-anywhere cloud sync became a popular feature for notes, documents, and photos. Early note sync services like Evernote focused more on convenient access rather than privacy, uploading note content to servers in an unencrypted form. It raised concerns over government surveillance and insider threats at these third-party companies being able to access private note data.

how does privnote work? In response, a wave of new encrypted note services popped up aiming to give anywhere access and peace of mind that notes remain confidential. The idea is your sensitive notes and documents are encrypted on your devices before syncing them through the cloud service’s servers. It means company employees and government agencies cannot access the decrypted content you unlock and view your notes with your encryption key.

Some key promises these types of services provide:

  • Encrypted sync and storage using industry-standard algorithms like AES-256-bit encryption
  • Zero-knowledge architecture you control the encryption keys
  • Open source apps and protocols allow transparency into their security models
  • Encrypted search in some cases allows searching content without exposing it
  • Some provide end-to-end encrypted chat options for secure communications
  • Availability on all major platforms: iOS, Android, Mac, Windows, Linux

With promises like these, encrypted cloud notes aim to alleviate privacy concerns while still enabling anywhere access convenience across all your devices. But let’s take a deeper look at how they work under the hood.

Encryption keys and architecture

The magic of making secure cloud notes work lies in the encryption algorithms and key architecture. Industry-standard algorithms used include:

  • AES (Advanced Encryption Standard) for encrypting/decrypting note content
  • RSA for handling the distribution of secret keys
  • PBKDF2 for strengthening password-based keys

Services will combine these algorithms in a multi-layered “defense in depth” approach. For example, note content itself is encrypted symmetrically with a strong AES key. Then the AES keys used to encrypt your data are further encrypted asymmetrically with your public/private RSA key pair. This all happens transparently in the background when you first set up an encrypted notes service.

The most critical part is making sure only you control the private keys required to decrypt and access the note content. This is accomplished by never sending private keys to the server and instead encrypting them locally with your account password via key derivation functions like PBKDF2.

When you enter your account password to access notes on a device, it re-derives your private keys to decrypt the downloaded note containers. The service provider’s servers see only encrypted blobs of data they cannot decrypt themselves. This zero-knowledge architecture isolates control of decryption keys entirely on the user side.