Memo App Encryption
Comparison 2026
AES-256 and provider-inaccessible content describe different properties. Compare 10 apps by which copies they protect, who controls the keys, and which settings you need to enable.
Start with the scope: TLS, encrypted storage, and E2EE protect different parts of a workflow. E2EE sync does not automatically encrypt local files or an exported PDF.
Reviewed September 9, 2026. The author develops Simple Memo. This comparison uses official product documentation; it is not a penetration test or an independent security audit of these apps.
TLS, encrypted storage, and E2EE
In transit: protect the connection
TLS protects traffic between endpoints, such as an app and its server. It does not hide content from a server that needs to process it. A service can receive a note over HTTPS and still read it for search or delivery.
At rest: identify the copy and the key holder
A local database, a sync server, and a backup are separate copies. Server-side disk encryption can coexist with the service holding decryption keys. Device-wide encryption and an app encrypting individual notes are also different controls.
E2EE: keep content decryption at the endpoints
End-to-end encryption encrypts and decrypts content on supported endpoints. Check metadata, public links, AI feature submissions, and decrypted exports separately. An app offering E2EE does not mean it is enabled for every note you already have.
Read cipher names and key ownership separately
AES-GCM combines encryption with authentication and produces a tag used to detect tampering. AES-CBC provides confidentiality, without authentication on its own; it needs a correctly designed separate authentication mechanism, such as a MAC. The name CBC alone does not establish that a product is compromised. See NIST’s GCM specification and its confidentiality-mode specification.
“256” describes a key length, not who holds the keys or how backups work. AES-GCM can be used within E2EE or just to protect local storage.
Zero-knowledge is used by storage products to describe designs where the provider cannot decrypt content. It is not a cipher name or a promise that no data is collected. Encrypted key material may be stored on a server; identify who can actually decrypt it and which data the promise covers.
10 apps: compare scope and settings before cipher names
Scroll horizontally to read the conditions and other copies. The table region also supports keyboard scrolling.
| App | Encryption scope | Settings and conditions | Other copies and access | Sources |
|---|---|---|---|---|
| Standard Notes | Encrypts content client-side for sync; documented cipher is XChaCha20-Poly1305. | Local data is encrypted when using an account. Account-free use needs a separately configured passcode or other encryption protection. | Check files exported or copied into another app separately. | Encryption scope · Cipher |
| Obsidian Sync | E2EE is the default choice for a remote vault; AES-256-GCM. | A remote vault created with standard encryption uses provider-managed keys. Check its setting and encryption password. | Obsidian does not encrypt the local Markdown vault. Disk encryption and local backups need separate protection. | Sync security |
| Notion | TLS 1.2 or later in transit; AES-256 at rest. | The documented controls are service-side encryption, distinct from full-note E2EE with keys held only by users. | Review published pages, guests, and integrations. Encryption does not narrow sharing permissions. | Security practices |
| Evernote | TLS plus AES-256 storage with Google-managed keys; selected text also supports passphrase encryption. | The documented selected-text cipher is AES-128-CBC. This is distinct from E2EE of the whole note and its attachments. | Text outside the selection, titles, and attachments do not acquire that passphrase protection. | Storage and transport · Text encryption |
| Appleメモ / Apple Notes | Standard iCloud protection encrypts Notes in transit and at rest. Advanced Data Protection (ADP) extends E2EE to iCloud Notes. | Check ADP and recovery arrangements. Shared notes retain ADP E2EE when every participant has ADP enabled. | Some metadata remains under standard protection. Exported PDFs and email attachments are separate copies. | iCloud protection |
| Google Keep | Encrypts data in transit and at rest and processes content to provide features such as search. | Do not interpret the documented protection as E2EE with user-only keys. | Review collaborators and account protection. Not using content for ads does not mean content is never processed. | Keep privacy and protection |
| Bear | Bear Pro encrypts individual notes with a Note Password. Version 2.4 added encryption for images, PDFs, and other attachments. | Add a password to the intended note and update syncing clients. Distinguish note encryption from locking the app. | Titles remain visible in the note list. Check the stated title and tag limits of iCloud ADP too. | Note encryption · 2.4 attachments · Sync scope |
| Joplin | Offers E2EE for sync when enabled. Native methods introduced in v3.2 use AES-256-GCM. | Follow the setup guide: enable on one device, finish syncing, then configure the key on other devices. | The sync encryption does not encrypt local data. Check device disk encryption too. | Setup · Native methods · Local data |
| Day One | New journals created since version 4.2 use E2EE by default, covering text and media. | Check older journals individually. The current FAQ directs users to copy entries into a new E2EE journal rather than convert standard encryption directly. | Check key copies: iCloud Keychain is E2EE; Day One’s separate iCloud key backup is not E2EE, even with ADP. Journal exports are separate copies. | E2EE FAQ |
| Simple Memo | Uses CryptoKit AES-GCM for the local Outbox and sent history, with new 256-bit keys stored in Keychain. | Email delivery is not E2EE. Content passes through the sending API and delivery provider, and a copy reaches the inbox. | Local encryption does not determine protection in the mail service or a connected Obsidian vault. | Technical policy |
For short notes sent to your own inbox, Simple Memo is another option. Review local encryption and the inbox’s storage and sharing settings separately.
Check five things before moving real notes
- Open the setting for existing data.Check the actual vault, journal, or shared note. A default for new data may not have changed older data.
- Keep the documented recovery method.Identify the sync password, encryption key, or recovery contact the product requires. Do not erase your only device as a recovery test.
- Review sharing and integrations.Public links and submissions to another service are separate from encrypted storage. Follow your organization’s approved destinations and sharing rules for work data.
- Sync one harmless sample with an attachment.Check that it opens on another device, the attachment arrives, and the expected encryption setting is shown. This functional check does not prove the cryptographic implementation is secure.
- Check exports and backups.Markdown, PDFs, email, and downloaded copies may leave the original app’s E2EE scope. Keep the original data until migration is verified.
Simple Memo’s scope and the copies after sending
Simple Memo encrypts its local Outbox and sent history with AES-GCM. In the shared cipher in the published app, new keys are 256-bit, stored in Keychain, and used through CryptoKit. This protects the specified local data.
The email route is not E2EE.Content goes over HTTPS to the sending API, through an external email delivery provider, and into the inbox. Encrypted unsent notes do not imply that delivery systems never process content or that no external server is involved.
Removing a completed item from the Outbox does not erase sent history, received email, or a connected note destination. A file deletion is not a promise of physical media sanitization. See the technical privacy explanation and data-flow guide for handling and retention.
If you save to Obsidian, local vault, sync, and backup protection depend on your configuration. Where provider-inaccessible content is a requirement, choose a destination and workflow that meet that E2EE requirement first.
Frequently asked questions
Does AES-256 mean E2EE?
No. AES-256 names a cipher and key length. E2EE depends on where encryption and decryption happen and who can use the keys. Server storage encrypted with provider-managed keys differs from content decrypted only at user endpoints.
How do AES-GCM and AES-CBC differ?
GCM combines encryption and authentication. CBC does not detect tampering on its own and needs a correctly designed authentication mechanism. A cipher name alone cannot rank the security of an entire app.
Does E2EE also encrypt files on my device?
Not necessarily. Obsidian Sync and Joplin sync encryption do not apply the same encryption to the local vault or database. Check disk encryption, local app protection, and backups separately.
Can Bear encrypt notes containing images and PDFs?
Since Bear 2.4, Bear Pro can encrypt individual notes with attachments. Add a password to the note and update the apps on syncing devices. Review visible titles and notes you have not encrypted separately.
Are older Day One journals automatically E2EE?
E2EE is the default for new journals since version 4.2, but older journals need checking. The current official FAQ advises copying entries into a new E2EE journal instead of directly converting a standard-encrypted journal.
Is email sent to myself from Simple Memo E2EE?
No. Local Outbox and sent-history encryption is separate from email delivery. Content passes through the sending API and external delivery provider, and copies remain in the mail service. Check inbox and connected-destination protection and sharing settings too.
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