There is a big difference between wanting to see someone else's messages and calls and having the right to do so. This guide addresses the latter: what Brazilian law actually allows, what records can be legitimately obtained, and through what means—including when the goal is to use them as evidence.
The starting point: secrecy is a constitutional rule.
O Article 5, XII, of the Constitution It protects the confidentiality of correspondence, telephone communications, and data. Breach of confidentiality is an exception, permitted by court order and, in the case of telephone communications, only for criminal investigation or criminal procedural instruction, in accordance with the law. Law 9.296/96.
Outside of this framework, unauthorized access to another person's device falls under... Article 154-A of the Penal Code — unauthorized access to a computer system — punishable by imprisonment from 1 to 4 years and a fine, which is aggravated if the content of private communications is obtained or if the material is disclosed.
What can you legitimately obtain?
Your own call logs
The operator provides the line holder with a call log for the plan, including numbers, date, time, and duration. This can be accessed through the operator's app or by request. It is your data; it does not depend on anyone's authorization.
Important: the statement shows who Who did he talk to and for how long? He doesn't save the content — the operator doesn't record the audio of the calls.
Records from your own device
Your call history, messages, and WhatsApp backup on your phone are yours. If the goal is to preserve something for future use, then... notarial deed In a notary's office, this is the appropriate instrument: the notary certifies what is on the screen, and this has much greater probative value than a loose printout.
A conversation you participated in.
You can record and present a conversation in which you are one of the participants. The Brazilian Supreme Court has ruled that a recording by one participant, without the other's knowledge, is admissible as evidence, except in situations protected by specific legal confidentiality. This applies to your own phone call and conversation—it does not authorize recording someone else's conversation.
Corporate device and minor child
The company can monitor the device it provides, with a written and informed policy. Parents and guardians can supervise their minor child, preferably in a declared manner and using an official tool.
The legal route, when the case is serious.
If the information is truly necessary—criminal investigation, custody dispute, asset investigation—there is a formal procedure. The lawyer can request the court to break telephone or telematic secrecy, and it is up to the judge to decide with justification. Once the measure is granted, the data arrives via the operator or platform, with the chain of custody preserved.
It's slower than installing a program, and it's the difference between a piece of evidence that counts and one that undermines the case itself.
Why evidence obtained through intrusion is often inadmissible.
Illegally obtained evidence is inadmissible in legal proceedings and contaminates any evidence derived from it. In practice, three consequences accumulate for the person who invaded the property:
- The material tends to be disregarded and is not taken into consideration by the judge.
- The conduct constitutes a separate crime, regardless of what the message revealed.
- This opens the door to claims for compensation for moral damages in civil proceedings.
It is not uncommon for someone to enter a process as an interested party and leave as a defendant — the message confirming the suspicion does not change that outcome.
Legitimate oversight: the official tools
For younger children, Google Family Link on Android and Usage Time On iPhones, they control screen time, approve installations, and show location, with the app visible on the device. Neither displays the content of conversations, and this boundary is intentional: usage patterns are tracked, not the intimacy of each message.
Google Family Link
AndroidFrequently Asked Questions
Can I request someone else's call log from my service provider?
No. The operator only provides it to the line holder. Third parties require a court order.
Is it legal to record my own phone call?
Yes, when you are one of the participants. Established legal precedent allows such recordings as evidence, except in cases of specific confidentiality requirements. Recording a conversation between two other people is considered wiretapping and requires judicial authorization.
Is a screenshot of a conversation valid as evidence?
It's worth more when authenticated. A notarized statement at a notary's office certifies the content displayed on the screen and better withstands allegations of manipulation than an isolated screenshot.
Does WhatsApp deliver the content of messages in transit?
It does not hand over the content because end-to-end encryption technically prevents it from doing so. It can provide, by court order, registration data and connection logs.
How long are the records kept?
The Brazilian Internet Bill of Rights establishes a minimum retention period of one year for connection logs and six months for application access logs. Therefore, when a case goes to court, acting early is important.
In summary
You have a right to what is yours: your call logs, your device, the conversations you participated in. For what belongs to another person, the path is through the courts—and that exists precisely for serious cases. The shortcut through surveillance software delivers evidence that is not valid and a criminal trial that is.
What to do, in order.
- Enable installation approval. It prevents new apps from appearing without your knowledge, which is half the problem.
- Combine before configuring. With a teenage child, an agreement on what will be monitored is worth more than any restriction—and survives discovery better.
- Set a limit per application, not just a total limit. Allowing free study time and restricting short video time works better than a single limit.
- Review the agreement every few months. Limits that don't match age become a source of conflict and challenges.
Where most people slip
- Don't believe promises of monitoring based solely on a phone number; it doesn't exist.
- Expecting to read WhatsApp conversations: end-to-end encryption prevents this, for any tool.
- Installing hidden software on an adult's cell phone is a crime under article 154-A, punishable by 1 to 4 years imprisonment.
- Disabling Play Protect to install files from outside sources is the most common vector for banking trojans.
Before installing: what's already on the device
To find a lost device, Find My Device and Find My iPhone are free and come standard: they sound an alarm even when the device is on silent, show it on a map, and remotely lock and erase it. It's worth checking today if they are activated — once lost, you can't configure them anymore.
Metadata and content: the law separates the two.
Much of the confusion surrounding this topic stems from mixing two different things. There is the content communication includes the text of the message, the audio, the photo, and what was said during the call. And there is also... metadata, which is the surrounding record: which number spoke to which number, on what day, at what time, for how long, from which antenna.
These are distinct regimes. The content has stronger legal protection and can only be accessed by court order in a criminal investigation. The record can be obtained in broader situations, and sometimes by the line holder themselves, directly from the operator.
In practice, this changes what makes sense to ask for. A detailed bill shows that there was a twenty-minute call at three in the morning. It doesn't show a single word of what was said. Anyone expecting to receive a transcript of a conversation when requesting a bill will be disappointed.
What appears on a detailed invoice
- Numbers called and received, with date, time, and duration.
- SMS messages sent, with destination and time — without the text.
- Volume of data consumed during the period, in blocks, without specifying which application.
WhatsApp, Telegram, Instagram, or any other app conversations don't appear on your bill. For the carrier, it's all just encrypted data traffic.
Retention periods: the clock ticking against you.
The Brazilian Internet Bill of Rights (Marco Civil da Internet) establishes a timeframe for how long records are kept, and this period is short. Internet service providers keep connection logs for one year. Application providers keep access logs for six months. After that, the data may simply no longer exist.
Those who discover a problem, spend months deciding what to do, and only then seek legal counsel often arrive too late. The registration that would resolve the issue has already been discarded as part of the company's normal routine, without anyone having acted in bad faith.
There is a way to hold back the clock: request the preservation of records. The interested party, the police authority, or the Public Prosecutor's Office can request that the provider keep that set of data for a longer period while access is being discussed. The request for storage is one thing; authorization to view the content is another, and comes later.
The practical approach is simple: if the matter is serious, the time to seek guidance is now, not in six months.
Cryptography limits even what the justice system can achieve.
Messaging apps with end-to-end encryption scramble the content on the sender's device and only unscramble it on the receiver's device. The company operating the service transports a packet that it itself cannot read.
This has a consequence that surprises many people: even with a court order, the platform cannot hand over the text of past conversations. It simply doesn't have it. What can be provided is account registration information, connection addresses, and profile information—metadata, again.
Therefore, the conversations that become evidence in legal proceedings almost always originate from a device, not from a request to the company. Someone had legitimate access to the cell phone and presented what was on it.
Where cryptography fails.
- Cloud backup. The backup may fall outside of end-to-end protection if the user has not enabled backup encryption.
- Notifications. The text that appears on the lock screen is not encrypted at the time it is displayed.
- Screenshots. After the message was read and photographed, it became a common image.
How to preserve what's on your own device.
If the conversation is on your phone, with you as a participant, you can record it. The common mistake is relying solely on screenshots, which are easy to dispute because anyone can create a similar image.
- Export the entire conversation directly from the app., with the function of exporting history. The continuous file is worth more than loose clippings.
- Don't delete anything., Neither the parts that don't favor you, nor the edited transcripts. An edited transcript loses credibility and can be used against the person who submitted it.
- Consider the notarial deed. In a notary's office, the notary navigates the device and describes what they see in a public document. This format tends to withstand challenges best.
- Put the device away. Switching phones and restoring backups in the middle of a legal dispute weakens the evidence.
The person who owns the phone line doesn't own the conversation.
Paying the bill does not create rights over the content. The person who signs up for a family plan is the contract holder with the operator, and this allows them to view the line's bill and manage the plan. It does not allow them to read the messages of the person using the device.
The same reasoning applies to a cell phone given as a gift and to a device paid for by one of the spouses. Ownership of the object and confidentiality of the communication are separate things, and the latter belongs to the people who conversed, including the person on the other end, who never participated in any domestic agreement.
The known exception is the supervision of a minor child, which exists because there is a legal duty of care — and even then it works best when it is declared, with an official tool, and not hidden.
