The TraceCrypt Protocol is an intentionally flawed protocol 🦠 which used to track close contacts securely, it uses privacy and security measures through cryptographic techniques 🔒. Despite its imperfections, this protocol shows a little bit tech skills lol.
The protocol unfolds through these key steps:
- ECC (Elliptic Curve Cryptography): Each participant generates a unique identifier using ECC's public key 🔑.
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Shamir's Secret Sharing: The identifier is split into multiple shares using the k-out-of-n Shamir's Secret Sharing scheme. This clever method ensures the ID can only be reconstructed when a minimum number of shares are combined, adding a touch of extra security 🛡️.
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Broadcasting Shares via UDP: These shares are broadcasted over the network using UDP, ensuring efficient and lightweight dissemination 📡.
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ID Reconstruction: Devices gather incoming shares and reconstruct the original ID when they collect the required number of shares. This step ensures that only those in close proximity and for a sufficient duration can obtain the ID, representing true close contact scenarios 🏷️.
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Generate Shared Key: Once the ID is reconstructed, devices perform the key exchange part to derive a shared secret key 🔑.
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Storing IDs in Bloom Filters (BFs): IDs are encoded and stored in BFs, which are efficient data structures and somehow privacy. Each BF holds records for a short period before being periodically sent to a backend server via TCP for cross-referencing with reported cases. The server then responds with infected status based on these matches 📊.
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Reporting Infected Diagnosis: If a diagnosis is infected, a client can upload its Bloom Filter (BF) to the backend server. This process helps notify others who may have been infected.
- Man-in-the-Middle (MiTM): An attacker capturing sufficient UDP broadcast shares could broadcast them widely, leading to potential false notifications
⚠️ .