From 293706c42d00c80888955485ee4d784c7a913011 Mon Sep 17 00:00:00 2001 From: KJ Date: Sun, 26 Feb 2023 10:41:53 +0800 Subject: [PATCH] update with pubkey_prefix tag --- N.md | 33 ++++++++++++++++++++++++++++----- 1 file changed, 28 insertions(+), 5 deletions(-) diff --git a/N.md b/N.md index a5f46f36..7b8d3bdd 100644 --- a/N.md +++ b/N.md @@ -12,13 +12,36 @@ It is useful to work with the ETH-compatible NFT, DID, and token ecosystem. ## Private key and Public key Each user has a private(secret)/public key pair. -Nostr uses the curve `secp256k1`, and the private and public keys are 32 bytes (64 chars in the hex). +Nostr uses the curve `secp256k1`, and the private key is 32 bytes (64 chars in the hex), same as BTC and ETH. +The nostr `pubkey` is 32 bytes, removed 02/03 prefix of a compressed 33 bytes public key. -The ETH address uses the same curve, but `pubkey` is 64 bytes (128 in hex). +The ETH address uses the same `secp256k1` curve, but public key is 64 bytes (128 in hex, or 65 bytes by insert 04 before the key). The address is from the SHA3 of the 64 bytes of public key with "0x" prefix and 20 bytes truncated of the hash result. +The 33 bytes public key can be converted to 64/65 bytes uncompressed public key, then to the ETH address, however, the 32 bytes nostr `pubkey` does not have enough information to derive the ETH address. -However, we can derive the 32 bytes public key to the uncompressed 64 bytes public key. -The following code shows we can get the correct ETH address: +We propose a optional `pubkey_prefix` field in the `tags`: + +```json +{ + "id": <32-bytes lowercase hex-encoded sha256 of the the serialized event data> + "pubkey": <32-bytes lowercase hex-encoded public key of the event creator>, + "created_at": , + "kind": , + "tags": [ + ["e", <32-bytes hex of the id of another event>, ], + ["p", <32-bytes hex of the key>, ], + ["pubkey_prefix": <1-bytes hex-encoded 02 or 03 prefix of the 33 bytes compressed public key>], + ... // other kinds of tags may be included later + ], + "content": , + "sig": <64-bytes hex of the signature of the sha256 hash of the serialized event data, which is the same as the "id" field> +} +``` + +Similiarly, when generating the `event.id`, we `sha256` the serialized event. +It increases less than 30 bytes but keeps the compatible with existing protocol. + +The following code shows we can get the correct ETH address with 33 bytes of public key: ```python import secp256k1 @@ -36,5 +59,5 @@ eth_pk.to_address() # the address from Nostr 32 bytes public key assert eth_sk.public_key.to_address() == eth_pk.to_address() # get the same address ``` -It demos that we can get the ETH address from the existing `pubkey`. +It demos that we can get the ETH address from the existing `pubkey` and `pubkey_prefix`. It should work with any other language with a suitable library.