CachetCachet Privacy Policy
Effective date: November 3, 2026
Operator: NU TECH SOFTWARE SOLUTIONS, INC.
Privacy contact: 3294009901@qq.com
This policy explains how we, the operator named above, handle information when providing Cachet. It covers the Cachet iOS app with its keyboard and share extensions, the Cachet Android app and keyboard, and the Cachet website (www.jlkrkre.cn). Cachet provides an on-device keyboard, on-device encryption and decryption, and timed messages that rely on a key server. No account is required.
In short: what you type, your message text and your access passwords are processed only on your device and are never sent to us. Our server stores only a random key, a random identifier, an expiration time and a read count for each message. We show no ads, use no analytics or tracking tools, and do not sell personal information.
1. What you type and your messages
Pinyin conversion, candidates, predictions, English suggestions, spelling correction, emoji search, and message encryption and decryption all run on your device (on the website, in your browser). We do not send your typing, message text, ciphertext or access passwords to Cachet servers, and we do not use them for cloud typing, advertising, profiling or model training.
When you type normally with the keyboard, the text goes into the app you are using, which handles it under its own policies. When you use "Seal the text in this field," that app has already received the plaintext, and Cachet cannot retract drafts or copies it has saved. Typing in the keyboard's own seal line lets Cachet encrypt the text first and insert only the ciphertext.
Ciphertext, links, pairing invitations and replies you share travel through the messaging app, clipboard or other channel you choose. Pairing invitations and replies contain the nickname you set and your public key, which recipients can see. Cachet contacts are people you pair with yourself; we do not read your address book.
2. Information stored on your device
The following stays on your device. Cachet has no cloud sync of its own and does not upload it to us.
| Information | Purpose and retention |
|---|---|
| Learned typing data | Words you picked, their pinyin, how often and when, and which words follow which, to improve candidates on this device. Text typed in the seal line and access passwords are never learned. You can clear it in settings; older entries are dropped when a size limit is reached. |
| Clipboard history | When on (the default), text the keyboard actually reads, when it was recorded and whether it is pinned, so you can paste it again. No time limit; by default up to 300 unpinned entries (100 or 1,000 selectable), oldest removed first; pinned entries don't count. |
| Phrases, custom shortcuts, recent emoji, preferences | Your chosen shortcuts and keyboard settings, kept until you change or delete them or remove the app. |
| Private-mode data | Your nickname, contacts and groups you add, public keys and your device's private key, used for pairing and private messages. Stored in the system Keychain on iOS, and encrypted in app-private storage with a key held in the Android Keystore on Android. Contacts and groups can be deleted in the app. |
| Timed-message key cache and status | Random keys, message identifiers, expiration times, read status, and whether this device created the message, so messages open across the app and keyboard and you can reread your own. Expired entries are no longer used and are removed on a later cache write, not wiped at the exact moment of expiry. After you open someone else's read-once message, its key is deleted at once and only an "opened" marker remains until the original expiry. |
Clipboard. The keyboard records history only while it is on screen and actually reads the clipboard (for example when a copied message opens automatically, or when you tap paste); it never reads in the background. Content the system marks as sensitive or concealed, such as passwords copied from many password managers, is not recorded. Plaintext you copy from a message opened in Cachet is marked and kept out of history. Unmarked sensitive text copied in other apps cannot always be recognized; don't add text you don't want kept to phrases, or delete it from history.
System backups.
- iOS: clipboard history and word-prediction learning are excluded from backups. Pinyin learning, phrases, custom shortcuts, preferences and the timed-key cache may be included in your iCloud or computer backups. Private-mode Keychain items are set to this device only.
- Android: system backup is turned off for the app, and the key cache, clipboard history and prediction learning are also excluded from device-to-device transfer.
Backups, restores and cross-device clipboard features are controlled by Apple, Google and your system settings. "Not uploaded to Cachet" does not mean no copy can ever exist outside your device.
3. Information handled by the key server
When you create a timed message, the app (or website) sends only its lifetime and the number of times it may be opened; the server generates a random identifier and a random key. Opening a message or checking its status sends only that identifier. The server stores the identifier, the key, the expiration time, the read count and the read limit, to provide expiration, read-once messages and "opened N times." These records contain no message text, ciphertext, access password, nickname or contacts.
The apps currently offer lifetimes of up to 7 days (the server accepts 30 seconds to 30 days). After expiry the server no longer hands out the key, and a cleanup task running every 10 seconds deletes expired keys; when a read-once message is opened it counts as read and nobody else can get the key. So that a reply lost on the network doesn't waste the message, current apps and the website send a random token when opening: the key is kept for at most 40 more seconds, retrievable only with that same token, and then deleted (for older apps and requests without a token, it is deleted in that read). The remaining record (identifier, times and counts, no key) is kept for 30 days after the original expiry, so clients can tell "expired" from "unknown," and then deleted.
Network information and logs. Any connection to the server necessarily involves your IP address, the time and the requested address. The iOS app makes one connectivity check when its home screen opens, without any typed content. Access logging is turned off for the key API (/v1/), and the server program logs only its own errors, not requests; its operating counters go by endpoint and status code, with no ids or addresses.
Quota pass. When many people share one network exit and hit the rate limit, the app and website automatically get a quota pass, giving that device its own allowance. It is random, lasts 24 hours and is held only in the device's memory. The server doesn't store it or tie it to a device or person; it only counts by it in memory and clears that within minutes.
The key database is not backed up or snapshotted.
Server location. The key server and website are hosted by Tencent Cloud in Hong Kong. If you use timed messages from another country or region, the request information above is transferred to and processed in Hong Kong. Your message text, ciphertext and access passwords do not leave your device as a result.
4. Website
On the website, encryption and decryption run in your browser, which only requests or reads keys from the server (Section 3). The website uses no cookies, analytics or third-party resources. The web server (nginx) keeps an access log for page and download requests: IP address, time, page requested, browser user agent and referring page. It is used to operate the site and defend it against attacks, and kept for at most 180 days. Key API requests are not in this log.
5. Permissions
- iOS keyboard "Full Access": needed for the keyboard to reach the key server, read the clipboard and share data with the main app; key vibration needs it too. Turning it on does not mean we upload your typing. Without it you can still type normally; only those features are unavailable. You can turn it off at any time in the Cachet keyboard options in iOS Settings.
- Paste: on iOS, reading what other apps copied is governed by the system paste permission. You can turn off "open copied messages automatically" and clipboard history in Cachet and paste yourself. On Android, only the keyboard currently in use can read the clipboard.
- Camera: used only when you scan a Cachet pairing QR code; the code is read on the device and no images are uploaded. If you decline, you can pair with a text invitation.
- Network: used only to reach the key server.
We do not request location, contacts or microphone access, do not use advertising identifiers, and include no third-party advertising, analytics or cross-app tracking tools.
6. Service providers, disclosure and security limits
We use Tencent Cloud to host our server. Tencent Cloud processes the information in Sections 3 and 4 only as needed to provide hosting, networking and security.
We do not sell or rent personal information, and do not share it for cross-context behavioral advertising. We disclose information we actually hold only when required by law or valid legal process, or to protect the security of the service, and only as much as necessary. Because we hold only random identifiers and keys, we cannot tell from them what a message says or who sent it.
Your messaging apps, Apple's and Google's system services, the App Store and TestFlight handle information they receive under their own policies; this policy does not replace them.
Security limits. A public message without an access password can be opened during its lifetime by anyone holding the ciphertext, including an operator who has both the ciphertext and the server key; it is not private communication limited to named recipients. Expiration and read-once cannot remove screenshots, copies or other saves a recipient has already made, nor device backups or intercepted key copies. Private mode uses keys paired on your device, but cannot protect a device someone else controls. See Security and transparency.
7. Your choices and rights
In Cachet settings you can clear learned typing data, turn off clipboard history, and clear unpinned history entries. Clearing history keeps pinned entries, which you delete one by one in the keyboard's clipboard panel; turning history off does not delete existing entries. Phrases, custom shortcuts, contacts and groups can be edited or deleted on their screens.
You can revoke permissions, remove the Cachet keyboard or delete the app in system settings. Deleting the app does not retract ciphertext you have sent, and cannot guarantee removal of system backups or leftover Keychain items; server records still expire as described in Section 3. Cachet has no accounts, so there is nothing to close, and we cannot delete content that exists only on your device.
For information we actually hold, you can email us at the address above to request access, correction or deletion, or to exercise other privacy rights under the law where you live (including California). We will respond within the applicable time limit and will not treat you differently for doing so. We will never ask for your private key or access passwords. Random identifiers are not linked to anyone's identity, so we may be unable to find records from your name or email alone.
8. Emails to us
Feedback, your email address and any attachments you send us are used only to answer and resolve your request, and are deleted within 12 months after it is resolved unless the law requires otherwise. Our contact mailbox is provided by Tencent QQ Mail and processed in mainland China. Please don't email passwords, private keys or message text we don't need.
9. Children
Cachet is not directed to children under 13 and does not knowingly collect information from them or ask for ages. If you believe we have received a child's personal information, for example by email, contact us and we will verify and delete it.
10. Changes and contact
When features, data handling or providers change, we will update this policy and its effective date; material changes will be shown prominently in the app or on this page, and any processing that needs your separate consent will ask for it first. Send privacy questions and requests to 3294009901@qq.com.