# Glossary

Reference of terms, acronyms, and technical concepts used in the FluxiQ PIX documentation.

## A-C

| Term | Definition |
|------|------------|
| **ACCC** | Accepted -- transaction accepted by creditor's institution |
| **ACSP** | Accepted for Settlement Processing -- transaction being processed |
| **ANS** | Acordo de Nivel de Servico (Service Level Agreement) -- BCB requires PIX settlement within 1.6 seconds |
| **BACEN** | Banco Central do Brasil (Central Bank of Brazil) |
| **BCB** | Same as BACEN -- Banco Central do Brasil |
| **COSIF** | Plano Contabil das Instituicoes do Sistema Financeiro Nacional -- standardized chart of accounts for Brazilian financial institutions (BCB Circular 4010) |
| **CPIC** | Certificado de Participante de Integracao Comunicacao -- ICP-Brasil certificate for mTLS authentication with BACEN |
| **CPIA** | Certificado de Participante de Integracao Assinatura -- ICP-Brasil certificate for XMLDSig message signing |
| **CPM** | Canal Primario de Mensagens -- primary BACEN message channel (port 16522) |
| **CSM** | Canal Secundario de Mensagens -- secondary BACEN message channel (port 17522) |
| **CSRF** | Cross-Site Request Forgery -- attack vector mitigated by double-submit cookie pattern |

## D-I

| Term | Definition |
|------|------------|
| **DICT** | Diretorio de Identificadores de Contas Transacionais -- PIX key directory managed by BCB |
| **DLQ** | Dead Letter Queue -- NATS stream for messages that exceed max retries |
| **E2E ID** | End-to-End Identifier -- 32-character unique transaction identifier |
| **EVP** | Endereco Virtual de Pagamento -- random UUID v4 PIX key type |
| **ICP-Brasil** | Infraestrutura de Chaves Publicas Brasileira -- Brazilian public key infrastructure |
| **ICOM** | Interoperabilidade de Comunicacao -- BACEN communication interoperability standard |
| **ISPB** | Identificador do Sistema de Pagamentos Brasileiro -- 8-digit institution identifier assigned by BCB |
| **ISO 20022** | International standard for financial messaging (XML-based) |

## J-P

| Term | Definition |
|------|------------|
| **JetStream** | NATS persistent messaging layer providing at-least-once delivery |
| **JWT** | JSON Web Token -- used for authentication (HS256, HttpOnly cookie) |
| **MED 2.0** | Mecanismo Especial de Devolucao -- BCB framework for PIX fraud recovery |
| **MFA** | Multi-Factor Authentication -- TOTP-based second factor |
| **mTLS** | Mutual TLS -- client and server certificate authentication (used with BACEN) |
| **NATS** | Neural Autonomic Transport System -- messaging middleware |
| **Netting** | Process of offsetting bilateral positions to reduce settlement amounts |
| **pacs.002** | ISO 20022 Payment Status Report |
| **pacs.004** | ISO 20022 Payment Return |
| **pacs.008** | ISO 20022 Credit Transfer (PIX payment) |
| **pacs.028** | ISO 20022 Status Inquiry |
| **PDNG** | Pending -- initial transaction status |
| **PIX** | Brazilian instant payment system (24/7/365, < 10 seconds) |
| **PSP** | Prestador de Servicos de Pagamento -- Payment Service Provider |

## Q-Z

| Term | Definition |
|------|------------|
| **RBAC** | Role-Based Access Control -- permissions checked via RequirePermission plug |
| **RFC 7807** | Problem Details for HTTP APIs -- standard error response format |
| **RJCT** | Rejected -- transaction rejected by creditor or BCB |
| **RSFN** | Rede do Sistema Financeiro Nacional -- BCB's financial system network |
| **RTRN** | Returned -- transaction returned via pacs.004 |
| **SPI** | Sistema de Pagamentos Instantaneos -- BCB instant payment system |
| **STLD** | Settled -- transaction fully settled (final state) |
| **TOTP** | Time-based One-Time Password -- MFA algorithm (RFC 6238) |
| **TPS** | Transactions Per Second -- FluxiQ PIX targets 5,000 sustained |
| **XMLDSig** | XML Digital Signature -- RSA-SHA256 signing for BACEN messages |
| **XSD** | XML Schema Definition -- used for BACEN message validation |

## Expected Outcome

This glossary provides quick reference for all technical terms and acronyms used throughout the FluxiQ PIX documentation.