1/21 Buckle up for some mind blowing cryptography updates by @dfinity! 🧵💥
Have you heard of Verifiably encrypted threshold key derivation (vetKD)?
If you missed the Community conversations with @gregoryneven and @aislingconn87 on the #IC.
2/21 Problems:
Managing user side encryption keys is hard, and easily/safely manage user side encryption keys limits cross-device syncing.
3/21 Solution:
Verifiably encrypted threshold key derivation (vetKD)
API Function:
derive_encrypted_key (master_key_id, transport_public_key, derviation_id) -> Encrypted Key
4/21 Verifiably encrypted threshold key derivation interface, allows any canister to call "derive _encrypted_key".
Transforming any string into an encrypted key through an API.
5/21 But How Is this Possible?
DKG to generate master key and shares.
Derived Keys are BLS signatures.
Generate your BLS Signature on a subnet.
Threshold signed.
Identity based decryption scheme for asymetric use cases.
6/21 Threshold BLS is a BLS digital signature aka Boneh–Lynn–Shacham (BLS) which allows a user to verify that a signer is authentic.
The scheme uses a bilinear pairing for verification, and signatures are elements of an elliptic curve.
7/21 Steps
Front end generates a transport key pair
Canister calls derivation interface
Derives key in Encrypted form
Only thing canister, nodes see is encrypted key
Basically combining transport public key+derivation key into single key. Then use derived key to encrypt/decrypt
8/21 Identity Based Encryption:
9/21
Canisters can store end-to-end encrypted user data (e.g., storage, messaging, social networks) without having to rely on browser storage for user-side secrets.
10/21 Applications this enables:
Canisters or individual users can encrypt messages under the public key of the subnet, so that they can be decrypted by calling the threshold key derivation interface which is secret-shared among the replicas.
internetcomputer.org/live-sessions#…
11/21 Encrypted file storage
Drop encrypted files onto a storage canister.
User generates a transport key pair, sends ingress message to storage canister, returns key derivation.
User can encrypt file, and store encrypted document in ENCRYPTED storage canister.
12/21 End to End Encrypted Messaging
Send encrypted message without first communicating with canister to derive key. Subnet derives encryption key, using asymmetrical decryption.
13/21 End to end Encrypted Social Networks.
Wow this one is pretty cool:
All posts are encrypted in order to enforce access policy defined by user who posts content. All content posted is fully encrypted and only visible to specified users.
14/21 Trading applications: Preventing front running on exchanges.
Miner Extracted Value (MEV) is a term you've probably heard recently.
It's resulted in over $683m in lost funds since 2020 on Ethereum Dex's.
With on-chain encrypted DEX's, you can encrypt transactions.
15/21 cont'd MEV:
Decrypt sequenced transaction, and execute only when order is filled. This also enables secret bid auctions, Time lock encryption, and Dead man switches.
16/21 Other use cases:
- BLS Signatures
- Untraceable transactions. No big deal.
17/21 Is this technology scaleable?
Threshold BLS is simpler then ECDSA, and can perform 1000's on encryptions per second depending on subnet size.
18/21 Encrypted Group chats are also possible depending on how derivation identities are chosen.
Encrypted email isn't really used frequently currently, but with this setup, it becomes much more feasible.
19/21 What are some limits to Threshold BLS?
BLS signatures are not quantum secure. Over the longer term—say, 2025–2030—STARK aggregation is expected to be a drop-in replacement for BLS aggregation.
20/21 What about Homomorphic encryption? The encryption techniques above are not fully homomorphic, but are big step.
Trusted hardware solutions are a good option, but are vulnerable to sidechannel attacks on SEV.
21/21 I hope you've found this thread helpful.
Follow me @WeekInDfinity for more.
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