Privacy notice

About this notice

This notice explains how Central Quants handles personal data when you visit centralquants.com, create an account, study, download materials, make a payment or contact us. It covers our website and the account-security administration described below. Payment providers and external websites have their own privacy notices.

Who runs this site

Central Quants is responsible for the personal data described in this notice.

Our team is based in Singapore.

For privacy questions, complaints, access, correction or withdrawal requests, contact the Data Protection Officer for Central Quants at contact@centralquants.com.

Contact: contact@centralquants.com. Use this company email for support and requests about your own records.

What is recorded when you have an account

We store your username, password hash, email address where supplied, device-binding identifier, account and access status, sessions and security settings. Self-registration also records your real name, your optional school-email declaration, registration time and the Terms version you accepted. We store a salted password hash, not your readable password. Device identifiers and account marks are pseudonymous identifiers, not anonymous data.

A username, real name, email address, password and acceptance of the Terms are required for self-registration; without them registration cannot be completed. The school-email checkbox is optional and is not currently used to make eligibility decisions. Your name is used to administer a personal account and is not displayed to other customers.

Before you verify the registration code, pending registration details remain in application memory for up to ten minutes. The outgoing verification email is separately queued. Session tokens are stored in your browser; the database stores their hashes. Authentication and device-change records help prevent unauthorized access.

Payments and referral codes

For membership and custom payments, we send Stripe your email address, order reference, purchase description, currency and quoted amount. When a referral discount is used, we also send its stable bank identifier, partner label, percentage and base amount. Stripe collects payment details on its hosted Checkout page. We do not receive or store your full card number or card security code.

We keep the account and order references, product or custom-payment category, original and charged amounts, discount attribution, payment-provider identifiers, payment/refund/dispute states and related times and event references. This supports fulfillment, accounting, fraud prevention, refunds and disputes. Authorized referral managers can see per-code aggregate paid-redemption counts and totals, not customer names, email addresses or individual orders. These aggregates can still be revealing where very few people use a code.

For monthly subscriptions, we also retain Stripe customer, subscription and invoice identifiers, subscription status, cancellation settings and paid access periods to manage renewals and access. The customer portal is hosted by Stripe.

Stripe may process transaction, device and network information for its own payment-security and legal purposes, and may send payment receipts. Its handling, international transfers and retention are described in its privacy policy.

Stripe privacy policy

Study activity and usage limits

To protect the question bank and members' work, the platform records which items each account opens, when, and from which device and network address. We use those records to limit bulk collection and sharing, to investigate account sharing, and to count new items in a rolling 24-hour window. A content version actually viewed before remains reopenable while access is current. We do not sell these records or show them to other customers. Authorized operators and service providers may process them as described in this notice; limited disclosure may also be necessary for legal obligations or a security investigation. Raw network and browser details are cleared after 90 days; a minimal history of opened items remains until one year after the account is closed. If an older closure date cannot be verified, the year starts when the old closure is first detected. An account may first open up to 40 new question bundles in a rolling 24-hour window (20 units each, 800 units total). Reopening a version actually viewed before costs no new disclosure units while access is current. A substantive new version counts as a new opening even when the older version was viewed. Historical views are credited against the content version actually published at the time, without a retroactive debit; uncertain history requires review and does not create a free reopen credit. Separate rolling 10-minute request allowances apply to networks, accounts and preview leases. A reopen may still be refused because of request throttling, expired access or a revoked grant. A request-allowance refusal gives a retry time; people sharing a network can affect one another.

Before a question body is served, the application records the account or preview identifier, time, session/device reference where available, IP address, browser information, question and publication version, included answer/explanation, prior-view status and watermark placement. If recording fails, the question is not served. Lists and counts do not create question-opening records. Authorized pack downloads are recorded as download activity and are treated separately from bulk question harvesting.

Requests admitted to application usage checks also record time, route category and cost for the network and, where relevant, the account or preview. These records do not contain question bodies or the full requested path. A refused over-budget debit does not add another debit record. Separate web-server logs may record the request path. Shared-network usage can affect your request allowance.

Security cases and appeals

Security monitoring records account-linked request and disclosure events, route categories, time-quality information, pseudonymous references and bounded indicators of prohibited automation or sharing. A case can retain a compact evidence summary, your appeal statement, notice/delivery status, eligible time and pauses, human decisions and an audit trail. We use verified account or identity mappings, where available, to administer restrictions across CQ-controlled services and communities; a shared IP address or uncertain identity match alone does not establish culpability.

Ordinary accounts currently receive monitoring without score-triggered sanctions. Live workflow exercises are restricted to designated test identities. Security cases and appeals are reviewed by authorized people; a watermark or risk indicator is evidence to evaluate, not a guarantee that someone broke the Terms. Where a separate community has no integrated enforcement connection, an authorized moderator must confirm the action manually.

If you look without an account

If you use the platform without an account, your preview lasts three minutes from the first question, firm, locked section of the library or learning path you open. Each question you open is recorded before it is shown — which question, when, your network address and your browser — under a number generated at random for that preview alone; the number is not derived from your address or your device, is linked to no account, and stops working when the preview ends.

A second cookie, whose value is the same for every visitor, remembers for one day that this browser has had a preview, so that another one costs a few seconds of computation.

A preview's three-minute lease lives only in server memory and a restart ends it. Even when you open no question, the application records your network address, route class and request cost for abuse limits; issuance of a new preview also counts against that network. A fresh preview lease is not linked to an earlier one.

Content identifiers and watermarks

Online questions carry visible account identifiers and coded marks, invisible characters in prose and, where published, account-specific content variants. These help trace unauthorized redistribution. A coded mark can be matched to an account by an authorized operator using the protected marking key; it is not anonymous. Authorized downloadable packs may use a common edition rather than an individual watermark.

The web server's access log

In front of the application sits a web server (Caddy) which writes one line per request: the time, the network address, the method and path, the status, the browser's user-agent and the page that linked here. Authorization, Proxy-Authorization, Cookie and Set-Cookie are deleted from that line before it is written, so no password and no cookie goes into the log. The files are rotated and deleted after 90 days, and the web server does that itself.

Cookies

The website uses the cookies below for login, security, registration, preview access and language preference. Blocking essential cookies may prevent these features from working.

We do not use advertising or third-party analytics cookies on this website. On Stripe-hosted Checkout or an external website, that provider may use its own cookies and collect device/network information under its own policy. External links do not give us control of those sites.

Purposes and legal grounds

We use personal data to create and secure accounts, deliver the service and authorized downloads, apply usage allowances, process payments and discounts, administer access, investigate abuse, review appeals, answer support/privacy requests and meet accounting or legal obligations. We do not sell personal data or use question-opening records for advertising.

We collect, use and disclose personal data for the notified purposes with consent, deemed consent or a permitted exception where applicable law allows it. Providing information to request registration or payment may authorize processing necessary for that request, within the limits of applicable law. We do not treat acceptance of the Terms as blanket consent to unrelated purposes. Where specific consent is required, we must obtain it before that activity. You may withdraw consent or raise an objection as described below.

Recipients and security

Personal data is accessible to authorized people who administer accounts, hosting, billing, support and security cases. Host administrators have technical access; that access is not exclusive to one person. Tencent Cloud provides hosting and email delivery, Stripe provides payment processing, and the operator keeps encrypted recovery copies. We limit access by role and use HTTPS, password hashing, restricted staff powers and encryption for backups. No system can guarantee absolute security.

We may disclose the minimum necessary information to professional advisers, payment/financial partners, competent authorities or CQ community moderators to meet legal obligations, handle disputes or enforce a reviewed account restriction. We do not publish case evidence or share it with other customers. Service-provider processing and disclosures remain subject to applicable privacy requirements.

Storage, backups and international processing

Application records are stored on our Tencent Cloud server. Operational recovery data is copied hourly and encrypted before off-server transfer. Encrypted copies are also transferred to the operator’s computer. The server backup policy keeps the newest 48 sets and daily sets from the last 14 days; off-server copies require manual retention review and have no automatic deletion schedule.

Our main application server is outside Singapore, while Tencent email delivery uses its Singapore service. Stripe processing and the operator’s recovery computer may be in other jurisdictions. Personal data can therefore be processed across borders, including encrypted backups. Transfers must meet applicable legal requirements, including comparable protection where the Singapore PDPA applies and requires it; encryption alone does not replace a required safeguard or transfer mechanism. Contact our privacy contact for information about transfers relevant to your data.

Email and support

Tencent Cloud email delivery receives your recipient address and message for registration/login codes, device-change notices and security notices. Security notices include a case reference and limited timing information, not your appeal statement or full evidence. Local delivery logs use shortened addresses; queued message files contain the actual recipient and message. Accepted files are removed, but failed or uncertain delivery may require manual reconciliation and cleanup.

When you contact us by email, we and the relevant mailbox provider process your address, correspondence and attachments to handle your request. Do not send passwords, verification codes or full card details. The website has no newsletter or advertising email programme. Transactional receipts may be sent by Stripe separately.

How long things are kept

Automatic schedules apply to the records below. Other categories require manual review as explained afterward.

• Automatic schedule The web server's access log: 90 days. The web server deletes the old files itself.
• Automatic schedule A preview lease: three minutes, and gone at a restart. It lives in memory and nothing writes it down.
• Automatic schedule What you type into the registration form: ten minutes, in the server's memory only, and gone at a restart. Once the code is entered it becomes your account, described above.
• Automatic schedule Application records: raw network, browser, device and session details in view records are cleared after 90 days; network-scoped request rows are deleted after 90 days. Detailed view, admission and device events are deleted after two years. Minimal opened-item history remains while an account exists and for one year after closure; anonymous preview item history is deleted after two years. For accounts closed before closure dates were recorded, when the old date cannot be verified, the one-year period starts when the old closure is first detected. A time-limited evidence hold with a recorded reason can delay the relevant deletion; the reason is deleted when the hold expires. The application removes overdue records before opening on startup and sweeps daily while running.
• Manual handling A message that could not be sent: kept on the server, as evidence of what went wrong, until the owner deletes it by hand. Nothing deletes these automatically.

Raw security events expire after 30 days. Account identity, payment/referral records, security cases, appeals, ban mappings, support correspondence and off-server backups do not currently have automatic deletion schedules. We review these manually and keep identifiable data only while necessary for the stated purpose or a legal obligation. Expired membership alone does not close an account or delete its records. Relevant evidence may be retained under a documented, time-limited hold. Contact us for review of a particular record; no claim of automatic deletion is made for these categories.

Your rights and requests

Contact either address above to request access or a copy of your personal data and information about how it was used or disclosed in the preceding 12 months, correction, account closure or deletion. Depending on the law that applies, you may also request restriction or portability, object to processing, or withdraw consent where consent is the basis. Withdrawal does not undo lawful earlier processing. You may complain to your competent privacy regulator or use any statutory remedy without contacting us first.

Include your username or registered email and what you want us to do. We may ask for proportionate verification of identity or authority; do not send identity documents unless we explain why they are needed. Requests are handled manually. We aim to acknowledge within seven days and respond within 30 days; a shorter statutory deadline takes priority. If the law permits more time, we will explain the reason and timetable within the applicable response period. Any lawful refusal or permitted fee will be explained.

Deletion is not unlimited: necessary accounting records, active claims, proportionate security evidence or legal obligations may require limited retention. We will explain material exceptions. Closing an account may end access and does not automatically refund a payment. Encrypted backups may retain earlier copies until replaced or manually removed; if recovery restores deleted data, the applicable deletion must be reapplied. Provider-held data may need a separate request to that provider.

Age eligibility

Accounts and purchases are intended for people aged 18 or older who can enter a contract. We do not collect dates of birth or perform routine age verification. If you believe a child has provided personal data or opened an account, contact us so we can review, close the account where appropriate and delete unnecessary data, subject to legal retention obligations.

Changes to this page

The date at the top identifies this notice version. Material changes will be highlighted on the website before taking effect where practicable, or sooner where the law requires. Any new purpose requiring consent will not be authorized merely by changing this notice. Existing personal data remains subject to applicable law.