A Witness That Can’t Be Silenced: How Hyperledger Fabric Protects Women’s Violence Reports in Brazil

In Brazil, four women are murdered every day because of their gender. In 2025, the country recorded a record 1,518 victims, the highest number since femicide became a distinct crime under Brazilian law in 2015. Behind each statistic is a woman who might, at some point, have called for help.

Many did call. Ligue 180—Dial 180—is Brazil’s national hotline for women experiencing violence. Launched in 2005 by the Special Secretariat for Women’s Policies, the service predated and later became a cornerstone of the broader protection framework established by the Maria da Penha Law in 2006. Originally an information line, it expanded in 2014 to receive and forward complaints to authorities. Today, it provides guidance, referrals, and a 24/7 channel for filing complaints. It is staffed by all-female, trained operators.

But the sheer scale of the operation creates risk. In 2024, the hotline handled over 750,000 interactions. With over 2,000 interactions per day flowing through multiple channels, including phone, WhatsApp, and email, and complaints routed to hundreds of organizations across Brazil’s protection network, the system depends on humans using a patchwork of legacy databases.

Documents can be misfiled. Records can be lost in handoffs between agencies. Data can degrade as it moves through systems that were never designed to talk to each other. And in systems handling evidence of serious crimes, there’s an additional risk that records could be deliberately altered or suppressed. For women considering whether to proceed with a report, the system’s integrity is as important as its existence.

Brazil’s Ministry of Women, the federal agency that oversees Ligue 180 and coordinates the national protection network for women, looked to its technology partners to see if an enterprise technology designed to make business transactions error- and tamper-proof could do the same for the records of women reporting crimes against them.

Recognizing the Need for Blockchain

Blockchain was originally associated with cryptocurrency and enterprises, but governments are increasingly finding it useful for a different reason: building verifiable trust into public services.

Brazil has been at the forefront of this shift. The SP156 platform of the city of São Paulo is the main digital services channel for the municipality, processing more than 150,000 immutable records per month to improve transparency and accountability in city services. The platform is operated by a consortium of two Brazilian companies: BrBPO, specialized in digital transformation of the public sector and in the implementation of blockchain networks, and Metasix Tecnologia (Metasix), which provides a citizen relationship management platform.

It was this same consortium that the Ministry of Women turned to for bringing immutability, auditability, and distributed trust to violence complaints. The Ministry needed a system in which:

• Recorded information could not be improperly modified,
• Reporting processes remained transparent,
• Highly sensitive data was protected,
• Every involved authority could be audited, and
• Risks of record loss, whether due to system failures, human error, or deliberate interference, were structurally reduced.

This called for a permissioned blockchain: controlled access, certificate-based authentication, fine-grained permissions, and a complete audit trail, all operating within the context of multiple existing systems and legacy databases.

Choosing a Platform: Hyperledger Fabric

BrBPO, in collaboration with Metasix, led the technical implementation. Together, they evaluated blockchain platforms against the specific requirements of a government system that handles sensitive victim data.

Hyperledger Fabric, an LF Decentralized Trust project, stood out for several reasons. Its permissioned network model provided the controlled access and governance this system required. Its support for private data collections meant sensitive information could be shared only among authorized participants. Certificate-based access ensured that organizations could join the network only with verified digital credentials. And Hyperledger Fabric’s support for smart contracts in JavaScript, Java, and Go gave the development team more flexibility with familiar languages.

Practical considerations mattered too. Hyperledger Fabric had strong existing adoption in Brazil, with a mature ecosystem and real production deployments. Its performance at scale exceeded what public blockchain alternatives like Ethereum could offer. And as an open source platform under LF Decentralized Trust, it provided something especially important for a public-sector client: vendor independence. No single private company controls the platform, its pricing, or its future direction, which is a critical consideration for government infrastructure designed to operate indefinitely.

Establishing Security, Privacy, and Governance

Given that the system handles victims' identities, information about accused individuals, and records involving institutional actors, security had to be built in from the start rather than bolted on later. Its Zero Trust architecture assumes no one is automatically trusted: every connection is verified, every transaction is digitally signed, and every piece of code is scanned for vulnerabilities before deployment.

The governance model is straightforward: the Ministry of Women controls who gets in. New organizations must request authorization to join the network, and the Ministry defines the rules for onboarding, approving business logic, and validating transactions. The network includes both public- and private-sector organizations, each with a defined role in the Ligue 180 ecosystem.

The system currently sustains one to two million transactions per month, with performance tracked in real time using industry-standard monitoring tools and stress-tested with Hyperledger Caliper, a benchmarking tool that simulates high transaction volumes to verify the network can handle peak demand.

Building the Solution

A team of seven professionals built the solution over eight months. The system had to do two things at once: connect to the existing patchwork of government databases and communication channels, and add an immutable blockchain layer on top to guarantee the integrity of every record passing through.

In practice, this meant building two interconnected stacks. The parts that users see and interact with — the interfaces for operators, the complaint forms, the connections to legacy government databases — run on conventional technologies including TypeScript, Node.js, React, PostgreSQL, and Java. The blockchain layer, built on Hyperledger Fabric, sits beneath all of this, doing the work that makes the system trustworthy: recording every complaint as an immutable entry that can be audited but never altered.

The architecture evolved as the project matured. Early on, the blockchain components ran inside containers on virtual machines. This architecture was functional, but difficult to maintain and monitor. The team gradually migrated everything to a cloud-native setup using Kubernetes, Terraform, and Ansible. The practical difference is that now, if something breaks, the system detects it and recovers on its own. Updates can be deployed continuously. And the team can monitor every layer of the system in real time, from blockchain transactions to server health.

The hardest technical challenge was getting all the pieces to work together securely. The system has many components, and every connection point between the blockchain and the conventional systems needed careful design and tight security.

Making the Invisible Visible

While there were technical challenges to overcome, the project’s most distinctive challenge was not technical; it was communicational. How do you demonstrate the value of a distributed ledger to citizens who may never have heard of blockchain or who think of it as Bitcoin?

The team’s answer was to make the technology’s guarantees visible. They developed user interfaces that exposed relevant blockchain data: blocks, digital signatures, and asset history. Rather than hiding the technology, they showed how complaints had been immutably recorded and could be independently verified. The blockchain wasn’t just working behind the scenes; it was proving itself to the people it was designed to protect, and to those tasked with protecting the victims.

Letting Trust Change Behavior

Following the implementation of blockchain on the Ligue 180 platform, the annual average of complaints rose from approximately 90,000 to 148,000 in just one year. While multiple factors likely contributed to this increase, including the August 2024 restructuring of Ligue 180 as an independent service and heightened public attention to femicide, the pattern suggests that system credibility played a role.

In many contexts, a 64% spike in violence complaints would signal a worsening crisis. Here, it signals growing trust. Women who might previously have stayed silent came forward because the system gave them confidence that their reports would be handled reliably. It wouldn’t be lost in a handoff, corrupted in a system migration, or buried in a backlog. The blockchain made the system’s integrity visible, and visibility changed behavior.

Across BrBPO's blockchain-enabled government platforms, the consortium has measured a 73% reduction in cost per interaction and an estimated return of R$27.10 for every R$1.00 invested in digital transformation.

What’s Next

Future versions will add decision-making algorithms using smart contracts for rule validation and integration with external data sources. The team plans to onboard new organizations from both the public and civil sectors, scaling through new Hyperledger Fabric channels and peers. With Brazil’s 27 states, future requirements may justify additional channels to keep data federated and secure.

The team's relationship with LF Decentralized Trust is a two-way street. In addition to building on Hyperledger Fabric, BrBPO has contributed directly to Hyperledger labs, including the Fabric Kubernetes Builder and the Fabric Galaxy Ansible Collection, tools essential for provisioning Fabric in cloud-native environments. Those contributions are ongoing, with planned development support for Hyperledger Fabric 3+, the next long-term support version, including updates to the Fabric Operator, Fabric Console, and Fabric Ansible Collection.

These technical plans are unfolding against a backdrop of significant political momentum. In November 2025, Ligue 180 celebrated its 20th anniversary. In February 2026, the Brazilian government launched the National Pact: Brazil Against Femicide, a coordinated effort across all three branches of government. A new decree formalized the hotline’s digital channels and required states to sign cooperation agreements to integrate into the network. Sixteen have already joined, with eight more in negotiation.

This expansion transforms Ligue 180 from a federal hotline into a connected national protection network, which is exactly the kind of scaling that blockchain was designed to support.