These nine are the projects I'm immersed in today. Before them came many others that are now part of the chain's past. They all share one premise: the proof is written where no one can erase it.
Active · 2026
Earlier blocks: many other projects, now in the history · genesis 0xea0d76…8cad
01
Block #01 / 09ActiveCertification
Ciertis
Your document, sealed on the blockchain.
Register the SHA-256 fingerprint of any file on Polygon or Ethereum without the file ever leaving your device. You get a PDF certificate with a verifiable QR code: timestamped proof of existence and integrity.
Blockchain development studio with 13 services: NFT contracts, custom tokens, DAOs and real-world asset tokenization. Live demo, multichain deployment and an audit before mainnet.
End-to-end encrypted messages or files for someone to open on a set date. Only the cryptographic fingerprint goes on Polygon: a tamper-proof timestamp and complete privacy.
White-label SaaS joining physical columbaria in the stadium with a digital legacy: memorials, matches attended, QR/NFC-authenticated memorabilia and private messages. All certified on-chain.
A place at the Spotify Camp Nou where members and fans record their stadium experiences on the blockchain: matches, visits and memories beside the pitch, timestamped and tamper-proof.
Spain's first tokenized debt issuance under the new Securities Market Law: a €5M security token backed by diamonds, supervised by the CNMV and traceable security by security on-chain.
A 3D neural network of Bitcoin nodes where transactions leap from node to node like lightning. Rotate it, change its density and fire your own discharges with a click.
A crypto wallet with nothing but your email address: no apps, no extensions and no seed phrases. Sign in with your email and start receiving, holding and sending crypto.
Half of my work is looking at the chain from the other side: following the money, finding the bug before the attacker does and designing systems that don't keep what they shouldn't.
01 · OSINT
On-chain investigation
Tracing funds across wallets, exchanges and mixers. Address attribution and flow maps ready for a report.
02 · FORENSICS
Crypto forensics
Reconstructing incidents, scams and thefts with verifiable on-chain evidence. Our own scam database.
03 · AUDIT
Smart contract audits
Manual and automated review before mainnet: reentrancy, access control, oracles, economic logic.
04 · ZERO-CUSTODY
Privacy by design
End-to-end encryption and architectures where sensitive data never touches a server. Only the fingerprint goes on-chain.
Console — felixle@sede
Illustrative simulation · fictitious data
Chapter III · Your block
Don't trust me.Seal something yourself.
Type some text or drop a file. Your browser computes its SHA-256 fingerprint and mines a real proof-of-work block. Nothing leaves your device.