Alternatives
Products that do what XSigi does
Blockchain-secured signatures and encryption made simple.
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TLDR, Let's Seal gives the finger to Adobe and every doc signing tool (docusign, google, etc) who pay to play with the Adobe Approved Trust List and then charge you for something that should be free. Currently even the person checking if a document/contract is sealed or code is authentic has to also be inside the same Adobe walled garden too. Verification, the part that should be free is the part everyone charges for. Thats the shape Let's Encrypt fixed for TLS, and I wanted the same thing for documents and files. The core idea therefore needed to go a bit beyond e signatures and i…
Jul 2026 · github.com
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2014 · blocksignit.com
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Free & OpenSource software for managing cold storage wallets
Apr 2026 · bitcoin-safe.org
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2023 · caches.xyz
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An OSS KMP crypto + PKI library with a comprehensive ASN.1 engine. Android and iOS targets come with hardware-backed crypto + key storage, and native biometric auth.
2025 · github.com
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2015 · stampd.io
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Hey HN, I’m Ilias, 19, from Paris. I built Ellipticc Drive, an open-source cloud drive with true end-to-end encryption and post-quantum security, designed to be Dropbox-like in UX but with zero access to your data, even by the host. What’s unique: Free 10GB for every user, forever. Open-source frontend (audit or self-host if you want) Tech stack: Frontend: Next.js Crypto: WebCrypto (hashing) + Noble (core primitives) Encryption: XChaCha20-Poly1305 (file chunks) Key wrapping: Kyber (ML-KEM768) Signing: Ed25519 + Dilithium2 (ML-DSA65) Key derivation: Argon2id → Master Key → encrypts all…
Oct 2025 · ellipticc.com
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Hi HN, we are the developers from Tuta (formerly Tutanota), the German end-to-end encrypted email provider, and we recently released the world's first post-quantum encryption for email. We have included a full technical write-up of the cryptography involved in these changes and we have released it for open public review. This document specifies TutaCrypt, a protocol designed for hybrid email encryption in Tuta Mail. The protocol combines a classical Elliptic-Curve-Diffie-Hellman key exchange with a post-quantum KEM. The goal is to replace the usage of RSA in Tuta Mail. In the remainder of…
2024 · tuta.com
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SasaSavic.ca recently launched a public cryptographic timestamping service designed to remain verifiable even in a post-quantum world. The platform uses SasaSavic Quantum Shield™, a dual-signature protocol combining classical and post-quantum security. Each submitted SHA-256 hash is: • Dual-signed with ECDSA P-256 and ML-DSA-65 (per NIST FIPS 204) • Anchored to the Bitcoin blockchain via OpenTimestamps • Recorded in a public, verifiable daily ledger API (beta, no auth required): https://sasasavic.ca/beta-api/ Example curl request: curl -X POST…
Nov 2025
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