> For the complete documentation index, see [llms.txt](https://blockgram.gitbook.io/blockgram-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://blockgram.gitbook.io/blockgram-docs/about-blockgram/core-features/share-encrypted-files-with-blockchain-proof.md). # Share Encrypted Files with Blockchain Proof BlockGram allows users to share sensitive files, media, and documents directly in Telegram chats with end-to-end encryption, while anchoring cryptographic proofs on-chain. This approach combines privacy, decentralization, and verifiability into a seamless file-sharing experience. #### Secure and Seamless File Sharing Traditional messaging apps offer limited security and verifiability for file sharing. BlockGram solves these challenges by providing: * Fully encrypted, peer-to-peer file transfers * On-chain anchoring of file metadata and hash signatures * Verifiable proof of authorship, timestamp, and authenticity * Optional permanent storage on decentralized networks All of this happens directly in Telegram without requiring extra apps, wallets, or complex setups. #### File Encryption and Access Control **Encryption Workflow** * Files are encrypted on the client device using AES-256 symmetric encryption * A unique key is generated per file and wrapped with the recipient’s public key using RSA or elliptic curve encryption * File chunks are transmitted via Telegram servers or optionally stored on decentralized networks like IPFS, Arweave, or Filecoin * Recipients decrypt files locally using their private key **Access Control** * Only the intended recipient can access the file * Optional expiration or revocation rights can be enforced via smart contracts **Storage Options** * Temporary in-chat delivery with encrypted payloads * Long-term decentralized storage with on-chain hash anchoring #### Blockchain-Verified Integrity Every file shared generates a cryptographic hash that is recorded on-chain. This creates a decentralized certificate of authenticity, ensuring the file has not been tampered with and can be independently verified. #### Advanced Use Cases * **Legal Documents:** Contracts and agreements can be shared with immutable timestamping and verified recipients * **Enterprise Workflows:** Encrypted reports with proof of delivery for compliance audits * **NFT-Backed Media:** Restrict file access to NFT holders, proving ownership or usage rights * **Time-Locked Sharing:** Smart contracts delay access or enforce download conditions #### Technical Stack * Client-side AES-256 encryption for files * RSA or ECC encryption for key wrapping * Decentralized storage via IPFS, Arweave, Filecoin * On-chain hash anchoring for integrity verification * Optional zk-SNARKs for future zero-knowledge access control #### Security and Privacy Features * End-to-end encryption ensures no intermediary can read files * On-chain hash anchors detect tampering or replay attacks * Metadata remains private, even with centralized storage * Planned zero-knowledge proofs will allow verification without revealing file content or user identity #### Benefits * Eliminates dependence on cloud drives or third-party sharing tools * Guarantees verifiable authenticity and authorship * Preserves privacy while enabling trustless, auditable exchanges * Enhances Telegram’s file-sharing with blockchain-level securityza --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://blockgram.gitbook.io/blockgram-docs/about-blockgram/core-features/share-encrypted-files-with-blockchain-proof.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.