1. Who We Are and What This Policy Covers
KyouStudy is provided by HungBok ("HungBok," "we," "us," or "our"). We are the controller of personal information that we receive through KyouStudy, except where a platform or third party acts as an independent controller for its own service.
This Policy applies to the KyouStudy mobile application for Android and iOS, the website at kyoustudy.com, the image-delivery service at img.kyoustudy.com, the content-reporting service at reports.kyoustudy.com, and related support services (collectively, the "Services"). Features may differ by platform, app version, country, and purchase status.
For privacy questions or requests, email [email protected]. This Policy does not replace the privacy notices of Apple, Google, a text-to-speech provider, a hosting provider, an advertising partner, or another third party that processes information under its own terms.
2. Privacy at a Glance
3. Information We Process
| Category | Examples | How it is used | When it is processed |
|---|---|---|---|
| Learning records and on-device study input | Selected exam and level, local search queries, card status, current study navigation, study sessions, answers and attempts, scores, mistakes and wrong-answer notes, spaced-repetition state, mastery state, bookmarks and favorites, collection rewards, daily activity, goals, streaks, and streak-freeze use. | To provide search, study, review, testing, statistics, collections, and progress-reset features. | Processed locally on the device. Search and navigation state may be transient; progress records are stored. |
| Preferences and system context | Interface language, appearance, selected course, text-to-speech voice, rate and volume, reminder settings and times, notification language, card-reveal state, and system locale, time zone, clock, and appearance settings read when a feature needs them. | To remember your choices, calculate dates and streaks, schedule reminders, and personalize the app on that device. | Stored or read locally on the device. |
| Purchase and entitlement information | Premium product identifier, localized product details, purchase state, purchase token on Android, transaction status on iOS, active entitlement, pending status, acknowledgement, restoration, expiration, refund, or revocation status. | To show products, complete or restore purchases, prevent incompatible duplicate purchases, and determine Premium access. | Processed by the app and Apple App Store or Google Play. We do not receive your full payment-card number. |
| Remote image request data | Requested image path, IP address, request date and time, protocol and response data, user agent on Android, device/network metadata ordinarily included in an HTTPS request, and cache validators such as ETag or Last-Modified. | To deliver optional study artwork securely, cache it, diagnose delivery failures, limit abuse, and protect the service. | Sent to img.kyoustudy.com and its hosting or delivery infrastructure when a remote image is requested. |
| Generated card images and sharing | A collector-card image that you choose to save or share and the learning content visible in that image. | To save the image to your photo library or hand it to the operating system's share sheet. | Created on-device. The destination you select receives the file; KyouStudy does not track the selected recipient. |
| Notifications | Reminder times, selected language, learned expressions selected for a reminder, streak status, freeze dates, message assignment, notification identifiers, and a platform push token if remote notifications are offered and enabled. | To schedule and display study reminders, service messages, or other notifications you permit. | Reminders are ordinarily scheduled locally. Platform push services may be used for a feature that requires remote delivery. |
| Text-to-speech requests | The word, character, reading, or sentence you ask the device to pronounce, plus voice, language, rate, and volume settings. | To play pronunciation through the operating system or installed TTS engine. | Handled by the device and selected TTS provider. A network voice or third-party engine may transmit text under that provider's policy. |
| Content-problem reports | A random request identifier; one of the eight displayed report types (image, audio, spelling/typo, reading/pronunciation, translation, meaning/explanation, quiz answer/logic, or other); study or quiz screen; exam, level, content type, content ID, stable key, content schema and version; a snapshot of the affected expression, reading, meaning, explanation, image path or audio metadata; and, for quiz reports, question ID and type, interaction and answer modes, prompt, options, and expected-answer information. Technical context includes Android or iOS, app version and build, OS version, phone or tablet, OS-provided device model, interface language, study language, UTC offset in minutes, and submission time. | To identify and reproduce the affected item, review and correct content or quiz logic, group duplicate reports, diagnose version- or device-specific problems, and protect the reporting service. | Sent over HTTPS to reports.kyoustudy.com only after you select a report type. Opening the menu sends nothing. There is no separate confirmation step or user-authored description. |
| Support and correspondence | Email address, name or other details you include, message content, attachments, and related correspondence. | To answer questions, investigate reports, enforce rights, and improve the Services. | Received only when you contact us or otherwise choose to send it. |
| Website preferences | Language and theme selections stored under KyouStudy browser-storage keys. | To remember the appearance and language of non-legal website pages. | Stored in your browser. The Privacy Policy and Terms are always displayed in English. |
| Optional account, sync, or cloud-backup data | Email address or provider-scoped account identifier, authentication tokens, synced learning records and preferences selected for the feature, device and sync timestamps, conflict state, and security logs. | To create or secure an optional account and provide backup, synchronization, restore, or cross-device access. | Processed only if an account or connected storage feature is offered and you choose to use it. Core study features may remain available without it unless a feature states otherwise. |
| Website and service logs | IP address, browser and device type, requested URL, referrer, timestamps, status codes, security events, and ordinary hosting/CDN logs. | To deliver, secure, and maintain the website and image service. | May be processed by our hosting, DNS, security, or content-delivery providers. |
| Analytics data | Pseudonymous app-instance, browser, cookie, or similar identifier; app and page opens; sessions; screens or page paths; engagement and feature interactions; app version; operating system; device category or model; browser; language; approximate region; acquisition or referrer information; purchase events; and technical performance data made available by Google Analytics. | To understand aggregate use, measure releases and acquisition, evaluate feature performance, troubleshoot problems, and improve KyouStudy. | Processed by Google Analytics for Firebase in the Android and iOS apps and by Google Analytics through the Google tag on the website. See Section 8. |
| Advertising data | IP address and general location inferred from it, advertising ID such as Android Advertising ID or IDFA where available and permitted, app-set or app-scoped identifiers, app launches and taps, banner ad requests, impressions and clicks, ads viewed, consent signals, diagnostics, performance information, and fraud-prevention data. | To request, deliver, limit, personalize where permitted, measure, frequency-cap, secure, and prevent fraud in banner advertisements. | Processed for free users when a Google AdMob banner placement is eligible to load, subject to regional rules, age treatment, consent, platform controls, network availability, and Premium entitlement. See Section 8. |
Core study features ordinarily do not require you to provide a name, email address, telephone number, postal address, government identifier, contacts, precise location, microphone recording, camera image, or payment-card number directly to HungBok. Content reports likewise do not collect an account, name, email address, advertising identifier, permanent device identifier, serial number, precise location, attachment, free-text description, or complete learning history. An optional account, support request, purchase, provider login, or other connected feature may process limited information needed for that feature. Payment credentials remain with Apple, Google, or the applicable payment provider.
Any AI-generated or AI-assisted voices and images supplied by KyouStudy are prepared independently of your personal media. KyouStudy does not ask for or upload your voice recording, voiceprint, portrait, or unrelated photos to generate those assets. Saving or sharing an app-generated collector card processes only the rendered card you deliberately select as described above.
4. Local Storage, Caches, Backups, and Device Transfer
App databases and preferences
Learning records are ordinarily stored in app databases inside the device's application storage. Preferences are stored in Android shared preferences or Apple UserDefaults. Static course content may be bundled with or delivered to the app. KyouStudy does not need to upload your learning history to operate offline core study features, but records you select may be transmitted if you enable an optional account, backup, sync, transfer, support, or other connected feature.
Image caches
Remote study images may be cached in memory and on disk to improve speed and reduce network use. Android limits the app-managed disk image cache to approximately 256 MB and may evict older files. iOS uses system URL caching with an approximately 256 MB disk capacity. Operating systems may clear caches at any time.
Platform backups and device transfer
Android backup is enabled, and iOS may include app data in Apple device backups according to system settings. As a result, local databases and preferences may be copied to Google, Apple, a computer, or a replacement device through an operating-system backup or transfer feature. Those backups are controlled by the platform provider and your account settings, not by a KyouStudy account. Resetting data inside the app or uninstalling the app may not delete an older platform backup.
5. Device Permissions and Services
- Internet: used for remote study images, user-initiated content reports, app-store billing and entitlement checks, Google Analytics, Google AdMob banner ads and consent management, website and legal-page access, security, and any support, account, sync, remote-notification, or other connected feature that is offered. A TTS engine selected on your device may independently use the internet.
- Notifications: requested when you enable reminders or another notification feature. Reminders are ordinarily scheduled locally, while a remote-notification feature may use Apple or Google push services. Notifications can be disabled in KyouStudy or system settings.
- Exact alarms, boot completion, and time changes on Android: used to place reminders at selected times and restore or reschedule them after reboot, app update, clock change, time-zone change, or permission change.
- Photos or media: iOS requests add-only photo-library access when you save a collector card. Android uses platform media APIs and, on Android 9 or earlier, may request legacy external-storage write access. KyouStudy does not use this permission to read your unrelated photos.
- Vibration and haptics: used for optional interface feedback and notification behavior.
- Text-to-speech: KyouStudy can query and invoke installed TTS services. The selected engine determines whether synthesis is local or network-based.
- Share sheet: invoked only when you choose to share a generated card. The operating system and selected destination control subsequent processing.
Denying or revoking a permission disables the feature that needs it but does not prevent use of unrelated core study features.
6. Network Connections, Remote Content, Content Reports, and Website Operation
KyouStudy may request optional study images from https://img.kyoustudy.com. The request reveals ordinary network data to the server and its infrastructure. We use that data to return the requested file, maintain security, diagnose failures, and prevent abuse—not to associate the image request with the contents of your local learning database or build an advertising profile.
Content-reporting connection
When you select a report type, the app sends the report fields listed in Section 3 to a dedicated Cloudflare Worker at reports.kyoustudy.com, which validates and stores accepted records in a dedicated Cloudflare D1 database. The report is not tied to a KyouStudy login because no login is required. The server returns a report identifier and does not use cookies to create a reporting profile. The app does not automatically retry a failed submission or send reports in the background.
Cloudflare's edge receives ordinary HTTPS connection data. The reporting Worker transiently uses the connecting IP address as a rate-limiting key before validating a submission, but the Worker does not write that IP address, request headers, or report body to application logs or the D1 report row. Cloudflare may independently process limited request, security, and operational metadata under its infrastructure terms and retention controls.
Website and other server communication
The website provides product and legal information and may include interactive, analytics, advertising, consent, or support features. It stores language and theme preferences in browser local storage and uses Google Analytics through the Google tag. Google Analytics and enabled website features may use cookies, local storage, tags, or similar technologies. You can clear or block browser storage through browser settings and use any consent or privacy controls presented on the site. Hosting, DNS, security, content-delivery, analytics, and advertising providers may process ordinary request and event data as described in this Policy.
Internet and server features can fail, time out, be delayed, or become unavailable because of connectivity, maintenance, rate limits, regional restrictions, provider outages, app-version incompatibility, or security controls. Except for an explicit local queue or retry function described in the relevant feature, KyouStudy does not guarantee that an interrupted request will be delivered. Your carrier or internet provider may charge for data use.
7. Premium Purchases and App Stores
KyouStudy uses Google Play Billing on Android and StoreKit on iOS to offer monthly and annual auto-renewing subscriptions and a lifetime non-consumable purchase when those products are available. Apple or Google receives and processes your store account, payment method, billing address, tax, purchase, refund, and transaction records under its own privacy notice. KyouStudy receives only the product and transaction information needed to show, complete, acknowledge, restore, and verify entitlement.
KyouStudy may evaluate entitlement on the device and may use HungBok's server or a service provider for server-side verification. A purchase token, transaction identifier, product identifier, app identifier, store account-scoped identifier, and verification result may be exchanged with HungBok, the relevant store, or a verification provider to validate entitlement, handle renewals or refunds, prevent fraud, and provide support. Google Play Billing may bring supporting Google Play services modules into the Android app; billing does not require KyouStudy to access precise device location. If a separate feature ever requests location, it will require an appropriate purpose and permission or notice.
8. Analytics, Advertising, and Consent
Google Analytics
KyouStudy uses Google Analytics for Firebase in its Android and iOS apps. The SDK is initialized with the app and may automatically record events and properties made available by Google, including first open, app open, session start, screen activity, engagement, app update, operating system, app version, device category or model, language, approximate region, and acquisition information. Google Analytics assigns a randomly generated app-instance identifier to a particular app installation. The current implementation relies on automatically collected events and does not deliberately create Analytics events containing exact studied expressions, prompts, answer text, wrong-answer contents, bookmarks, notification contents, complete learning records, names, or email addresses.
The KyouStudy website uses Google Analytics through the Google tag. It may process page URL and title, referrer, browser and device information, approximate region, interactions, and first-party cookies or similar browser identifiers. Analytics is used for aggregate reporting, acquisition and engagement measurement, feature and release evaluation, troubleshooting, and service improvement. It is not used to retrieve the contents of the app's local learning database or the body of a content-problem report.
Analytics collection and available controls differ by platform, browser, region, and configuration. Browser cookie controls and Google's browser opt-out tools may restrict website measurement. Resetting app data or uninstalling the app stops that installation from sending future events, but does not itself erase information already retained by Google Analytics. Where applicable law requires consent or another choice, we provide or honor the required mechanism before using the affected data for that purpose. User- and event-level Analytics retention is configured for no more than 14 months; aggregate reports and data that Google processes independently may follow different periods.
Google AdMob banner advertising
Free users may receive Google AdMob banner advertisements on selected screens. KyouStudy currently uses fixed-size or adaptive banner placements and does not use interstitial, native, or rewarded-ad placements. A banner request is made only after the app resolves that the user is not Premium, the placement is eligible to load, and Google's consent information indicates that ads may be requested. Premium users with a successfully resolved entitlement are not shown KyouStudy's covered banner placements.
The Google Mobile Ads SDK may automatically collect and share the advertising data listed in Section 3, including IP address and IP-derived general location, product interactions, banner ad requests, impressions and clicks, diagnostics and performance information, ads viewed, device or app-scoped identifiers, and Android Advertising ID or IDFA where available and permitted. Google and participating advertising partners use this information for ad delivery and personalization where permitted, contextual or limited advertising, frequency capping, measurement, reporting, security, and fraud prevention. The selected banner and its destination are controlled by Google or the relevant advertising partner; selecting it may open an external app or website.
Core learning records—including exact studied content, answers, scores, wrong-answer notes, favorites, TTS text, and reminder content—and content-report snapshots are not provided to advertising partners for ad personalization. Purchase verification, consent records, security, fraud prevention, and provider-required measurement may continue even when banners are not displayed.
Consent and platform controls
- KyouStudy uses Google's User Messaging Platform to obtain and refresh consent information, show a consent form when Google determines one is required, decide whether an ad request may be made, and make a privacy-options entry available when required. An advertising consent choice does not by itself delete prior Analytics or advertising records.
- On iOS, KyouStudy requests App Tracking Transparency permission before accessing IDFA or tracking across other companies' apps or websites when Apple rules require it. Denial does not block core study features.
- On Android, you can reset or delete the Advertising ID in system privacy settings. Limited-ad and app-scoped identifiers may still be used for delivery, security, frequency capping, and fraud prevention.
- Where law provides a right to opt out of targeted advertising or the sale or sharing of personal information, KyouStudy provides or makes available an appropriate "Privacy options," "Do Not Sell or Share," provider, browser, or platform mechanism.
- Where we know a user is below the applicable age for personalized advertising, we request age-appropriate, restricted, contextual, or non-personalized treatment and do not knowingly use that user's data for personalized ads.
SDK versions, advertising partners, data uses, retention settings, and controls may change. Material changes are identified in the app, consent interface, store disclosure, or the live version of this Policy as appropriate. Google's disclosures are available in the Google Analytics for Firebase documentation, the Google Mobile Ads Android data disclosure, the Google Mobile Ads iOS data disclosure, and the User Messaging Platform guide.
9. Third-Party Services
| Service category | Provider or destination | Relevant processing |
|---|---|---|
| App distribution, billing, entitlement, refund, and backup | Apple and Google | Store account, purchase and transaction information, fraud prevention, device backup, and platform services. |
| Remote study images and website delivery | HungBok's hosting, DNS, security, and content-delivery providers | IP address, request metadata, security logs, and requested resources. |
| Content-problem reporting | Cloudflare Workers, D1, DNS, security, and access-control infrastructure, operated for HungBok | The content-report and technical fields described in Section 3; transient IP-based rate limiting; ordinary request, security, and operational metadata. The D1 report row does not store the connecting IP address. |
| Text-to-speech | Apple speech services, Android system TTS, or the installed engine and voice you choose | Text to synthesize, voice/language settings, and ordinary service metadata. Network handling depends on the selected engine. |
| Photo saving and sharing | Apple Photos, Android media storage, operating-system share services, and the app or recipient you select | The generated image and visible learning content you choose to save or share. |
| Support email | Your email provider, our email provider, and any service you use to send attachments | Sender information, message, attachments, delivery metadata, and correspondence. |
| Optional account, backup, and sync | HungBok and the authentication, database, hosting, or cloud-storage provider identified when the feature is offered | Account identifiers, authentication and security data, and the learning records or preferences you choose to store, back up, synchronize, restore, or transfer. |
| Analytics and banner advertising | Google, through Google Analytics for Firebase, the Google tag, Google AdMob, User Messaging Platform, and participating advertising partners | The analytics, advertising, consent, identifier, interaction, diagnostic, performance, and fraud-prevention data described in Section 8. |
10. Purposes and Legal Bases
Where law requires a legal basis, we process information as follows:
- Contract and requested service: to deliver app features, receive a content-problem report you deliberately submit, provide optional accounts or sync, deliver remote images, process purchases and restoration, provide support, save images, share content, and complete other actions you request.
- Legitimate interests: to review and correct reported content, group duplicate reports, secure and maintain the Services, prevent fraud and abuse, diagnose failures, improve performance, understand aggregate use where permitted, protect legal rights, and communicate about the Services. We balance these interests against your rights and expectations.
- Consent: for optional device permissions, non-essential browser storage, personalized advertising, tracking, or analytics where consent is legally required. You may withdraw consent prospectively.
- Legal obligation: to retain required transaction or tax records, respond to lawful requests, protect users, and comply with applicable law and platform rules.
12. Retention and Deletion
- Local learning records and preferences: remain until you reset them, uninstall the app, clear app storage, or a platform backup or transfer replaces them.
- Cached images: remain until evicted by cache limits, cleared by the app or operating system, or removed when the app is uninstalled, subject to backups.
- Store records: are retained by Apple or Google under their policies. KyouStudy's local entitlement state remains until refreshed, cleared, or removed with app data.
- Optional account, backup, or sync data: is retained while the feature or account is active and for a limited period afterward as needed for restoration, security, fraud prevention, dispute handling, or legal obligations. Available deletion controls and any provider-specific period are disclosed with the feature.
- Website and delivery logs: are retained only as long as reasonably necessary for delivery, security, abuse prevention, and troubleshooting, subject to provider configuration and legal requirements.
- Content-problem reports: accepted live report records and their affected-content or question snapshots are retained for no more than six months from submission. When a report is marked fixed, duplicate, or rejected, it is scheduled for deletion within three months after that decision, without extending the original six-month maximum. An automated task checks for and deletes expired report and item rows daily. HungBok may delete a report sooner when it is no longer needed.
- D1 recovery history after report deletion: a logically deleted report may remain recoverable only within Cloudflare D1 Time Travel's rolling recovery window. Cloudflare currently provides up to 7 days on Workers Free and up to 30 days on Workers Paid. It ages out of that recovery history automatically unless retention is required by law or a separate incident-preservation obligation applies. HungBok does not create a separate long-term report backup.
- Support correspondence: is normally retained for up to 24 months after the matter is closed, and longer only when reasonably necessary for an unresolved dispute, security issue, legal obligation, or rights record.
- Analytics and diagnostics: when enabled, identifiable event-level retention is configured for a limited period reasonably suitable for product analysis, generally no more than 14 months unless security, fraud, incident-response, or legal needs require longer. Aggregated or de-identified reports may be retained longer.
- Advertising: advertising, consent, measurement, and fraud-prevention providers retain information under their published policies and configured controls. Applicable provider details are identified through the live Policy, consent interface, or app and store disclosures.
You can reset learning information from KyouStudy settings. You can clear app storage or uninstall the app for broader on-device deletion. You must separately manage platform backups, saved photos, shared copies, email correspondence, store purchase records, and information already retained by third-party analytics or advertising providers. If an optional KyouStudy account or connected-storage feature is available, use its deletion control or contact us for data under HungBok's control. We cannot remotely locate or erase records that remained only on your device.
13. Your Choices and Privacy Rights
Depending on where you live and subject to legal exceptions, you may have the right to request access, correction, deletion, restriction, portability, or objection; withdraw consent; opt out of sale, sharing, targeted advertising, or certain profiling; and appeal a denied request. You may also complain to your local privacy or data-protection authority.
You can exercise many choices directly: disable notifications, change TTS engines, deny photo access, avoid remote images, clear website storage, manage platform backups, manage or cancel store subscriptions, and use the analytics, advertising, consent, and privacy choices made available in the app, website, operating system, or provider settings.
To submit a request, email [email protected] with enough detail for us to understand the request. If the request concerns a content report, include its report identifier if available, approximate submission time, report type, affected content, app version, and device model. Because reports do not contain an account or contact identifier, we may be unable to reliably locate a particular report or verify that it was submitted by you without this context. We may ask for information reasonably necessary to verify your authority without requesting more information than needed. We will not discriminate against you for exercising a privacy right. An authorized agent may submit a request where applicable law permits.
14. Security
We use reasonable technical and organizational measures appropriate to the Services, including app sandboxing; HTTPS for remote images, reports, and legal pages; strict report request validation and size limits; rate limiting; a dedicated report database; automated deletion; platform-verified billing flows; bounded image downloads; and Cloudflare Access plus server-side token verification for the report administration interface. No method of storage or transmission is completely secure. Protect your device, platform account, email, backups, shared images, and screen lock, and install operating-system and KyouStudy updates.
15. Children's Privacy
KyouStudy is an educational app but is not directed to children under 13, and we do not knowingly collect personal information from a child under 13 without legally sufficient authorization. Optional account or connected features may be restricted by age or require a parent or guardian. A parent or guardian who believes a child has sent personal information to us should email [email protected]; we will review the report and delete information where required.
When analytics or advertising is used, we apply age-appropriate treatment and any required parental-consent, under-age, contextual-ad, or restricted-data settings. We do not knowingly personalize ads to a child below the applicable age of consent.
16. International Processing
Apple, Google, Cloudflare, hosting providers, TTS providers, email providers, and analytics or advertising providers may process information in countries other than the one where you live. Those countries may have different data-protection laws. Where required, we rely on an adequacy decision, contractual protection, provider certification, consent, or another lawful transfer mechanism.
17. Changes to This Policy
We may update this Policy when KyouStudy's features, content-reporting system, data flows, providers, Analytics, AdMob banner advertising, purchases, AI-assisted media, platform requirements, or law change. We will post the revised Policy with a new effective or updated date and provide additional notice in the app or website when reasonably appropriate. If a change requires consent, we will request it separately before relying on that consent.
18. Contact
HungBok
KyouStudy privacy contact
Email: [email protected]
Website: https://www.kyoustudy.com/