# Cashu

> Electronic cash for payments online, in person, and around the world.

Cashu is a free and open-source Chaumian ecash protocol built for Bitcoin, enabling private, secure, and instant digital payments.

Cashu is a digital bearer token system that functions like physical cash but for online payments. It uses blind signatures to preserve user privacy while ensuring secure transactions. The protocol allows anyone to run their own mint and build wallets or voucher systems with near-instant, low-cost payments integrated with Bitcoin.

- Type: Project
- Sector: Privacy & Confidentiality
- Status: Active
- Founded: 2022-09-01
- Profile: https://thegrid.id/profiles/cashu

## Products

- [Cashu Protocol](https://thegrid.id/profiles/cashu): Cashu implements Chaumian blind signatures to create a digital bearer token system that preserves user privacy. The protocol enables instant peer-to-peer transactions and integrates with Bitcoin through mints where users can deposit and withdraw funds. (Payments Infrastructure & Orchestration, Live, Main Product)
- [Nutshell](https://thegrid.id/profiles/cashu): Nutshell serves as both a reference implementation of a Cashu mint and wallet. It allows users to run their own Cashu mint while providing wallet functionality for storing, sending, and receiving ecash tokens. (Wallet, Live)

## Links

- [Main](https://cashu.space)
- [Blog](https://blog.cashu.space)
- [Documentation](https://docs.cashu.space)
- [Twitter / X](https://x.com/CashuBTC)
- [Telegram](https://t.me/CashuBTC)
- [GitHub](https://github.com/cashubtc)

## Legal

This data is provided under two licensing models.

Model 1 - open data. The open data core is licensed under the Open Database License (ODbL) — a copyleft/share-alike license allowing free use, modification, and sharing for any purpose. Attribution is required: include "Powered by The Grid" linking to https://thegrid.id wherever the data is used. Derivative databases must be shared under ODbL terms. Trademarks, logos, and brand names (marked "Special TPIP") are not covered by the ODbL. For ML/AI use: training datasets that substantially extract ODbL data are Derivative Databases and must be shared under ODbL if publicly used; models must be attributed in documentation.

Model 2 - commercial licenses. The Grid Data Service (TGDS) is also available as a commercial license. See [Web Services Terms](https://about.thegrid.id/legal/web-services-terms) for commercial use that is not covered by the open data service.

The following applies to both licensing models.
- All data is provided AS IS with no guarantees of accuracy.
- The Grid does not provide investment, legal, or tax advice, and
- a project's presence in The Grid's data does not imply endorsement.


- [Data Licensing & Disclaimers](https://about.thegrid.id/legal/data-licensing-and-disclaimers): Licensing models and disclaimers
- [Open Data (ODbL)](https://about.thegrid.id/legal/open-data): Open Database License terms and scope for The Grid's open data service.
- [Attribution Guidelines](https://about.thegrid.id/legal/open-data-attribution-guidelines): How to attribute The Grid's data when using the open data service.
- [Web Services Terms](https://about.thegrid.id/legal/web-services-terms): commercial Terms for using data services.
- [All Legal Documents](https://about.thegrid.id/legal): Full index of terms, policies, and disclosures

## Optional

- [TGS Field Descriptions](https://github.com/The-Grid-Data/workspace-public/blob/main/references/tgs-field-descriptions.md): Schema field definitions for The Grid's data model
- [TGS JSON Structure](https://github.com/The-Grid-Data/workspace-public/blob/main/references/tgs-json-structure.md): Data model structure and relationships
- [Product Type Definitions](https://github.com/The-Grid-Data/workspace-public/blob/main/references/product-type-definitions.md): Definitions for each product type
- [Product Type Classification](https://github.com/The-Grid-Data/workspace-public/blob/main/references/product-type-classification.md): Guide for classifying products into types
- [Grid MCP Guide](https://github.com/The-Grid-Data/workspace-public/blob/main/grid-search/skills/grid-query/references/grid-mcp-guide.md): How to query The Grid programmatically via MCP