We will never sell your data. We will never send you spam. Registering a number to stop marketing should not create a new marketing audience. That is the starting point for 0TXT's design. We do not use the consumer register for promotional texts or upload registered numbers to advertising platforms.
We only text you when you request a verification code. After registration, there’s nothing else you need to do. The code confirms that you control the number. You do not need to maintain a consumer account, renew a subscription or keep returning to check lists. The preference remains active until it is removed.
Your number is processed before it is protected
When you submit the registration form over HTTPS, the application receives the full number so that it can validate it and send the requested code. It converts the number to a consistent international format. This lets the Australian local version and the international version match correctly without maintaining two unrelated identities.
The number is therefore present in application memory during that work. It would be misleading to say that 0TXT never sees it. The SMS provider also needs the destination to deliver your requested code. Our current provider is TouchSMS, which handles its records under its own privacy policy.
The register stores a keyed fingerprint
The dedicated global registry record contains a keyed fingerprint produced with HMAC-SHA256, together with information such as the preference and verification time. It does not store a plain full phone number in that registry field. Each record has a separate identifier, rather than using the phone number as its primary key.
A useful way to understand a fingerprint is as a repeatable comparison value. The application can process a business's submitted number in the same way and check whether the values match. It does not need to give the business the original register entry.
The secret key matters. Phone numbers have a limited range of possible values, so a simple unkeyed hash could be tested against lists of candidate numbers. The keyed process adds a secret that is held outside the database. A person with only the registry table does not also obtain that key from the table.
Temporary and retained numbers use encryption
While verification is pending, the destination is encrypted and the code is stored as a separate keyed value. Successful use, cancellation or expiry clears the verification secrets; scheduled cleanup removes remaining request metadata under the published retention process.
A business can choose to retain its own contact mappings for continuing matching. Where a full number is retained for that purpose, it is encrypted using Fernet with an encryption key separate from the fingerprint key. Fernet's documentation explains that this is authenticated symmetric encryption and that keeping the key secret is essential.
On the HAL installation, the application keys are held in private configuration outside the database and public web directory. Copying the protected database fields alone therefore does not also provide the key needed to decrypt retained numbers. Protecting and backing up the keys remains an operator responsibility.
A database copy can still contain personal information
These protections are specific, not absolute anonymity. Timestamps, relationships, external references and masked last digits can still be informative. The register and related records must still be treated as personal information.
The claim also applies to dedicated phone fields, not arbitrary text entered by people. Businesses and operators should not copy full phone numbers into names, notes or external-ID fields. Those fields have different purposes and are not a substitute for the protected phone fields.
If an attacker obtains the running server and its keys as well as the database, the risk is different from a database-only copy. An authorised application can decrypt retained mappings to perform permitted work. No responsible explanation should turn encryption into a promise that a complete server compromise is harmless.
Businesses check the contacts they already hold
A participating business submits its own contacts and receives suppression decisions about those rows. It cannot download a master list of registered people, obtain the global fingerprint key or browse another business's contacts. The result lets it remove marketing recipients; it is not a source of new prospects.
This is why registration is not a newsletter signup. There is no email address required for the consumer register, no promotional subscription hidden in the verification step and no need to keep doing tasks after registration.
Removal has a clear scope
You can verify your number to leave the voluntary register. An authorised super-admin can also remove a global entry and its verification requests. An old code cannot recreate that entry, although you can request a new code and register again later.
Earlier company-specific opt-outs remain. Historical backups and TouchSMS's own records are also separate from the active registry; removal is not a claim of instant erasure from every system. Read the privacy notice for scope and contact details, or the methodology page for the process before choosing to register your number.