nip-44: remove author names and arbitrary line-breaks.

44.md

@@ -2,7 +2,7 @@
 
 ## Encrypted Payloads (Versioned)
 
-`optional` `author:paulmillr` `author:staab`
+`optional`
 
 The NIP introduces a new data format for keypair-based encryption. This NIP is versioned
 to allow multiple algorithm choices to exist simultaneously.
@@ -22,12 +22,11 @@ The scheme has a number of important shortcomings:
 - Limited message size leak: padding only partially obscures true message length
 - No attachments: they are not supported
 
-Lack of forward secrecy is partially mitigated: 1) the messages
+Lack of forward secrecy is partially mitigated by these two factors:
-should only be stored on relays, specified by the user, instead of a set of
+  1. the messages should only be stored on relays, specified by the user, instead of a set of all public relays.
-all public relays 2) the relays are supposed to regularly delete older messages.
+  2. the relays are supposed to regularly delete older messages.
 
-For risky situations, users should chat in specialized E2EE messaging software and limit use
+For risky situations, users should chat in specialized E2EE messaging software and limit use of nostr to exchanging contacts.
-of nostr to exchanging contacts.
 
 ## Dependence on NIP-01
 
@@ -35,14 +34,9 @@ It's not enough to use NIP-44 for encryption: the output must also be signed.
 
 In nostr case, the payload is serialized and signed as per NIP-01 rules.
 
-The same event can be serialized in two different ways,
+The same event can be serialized in two different ways, resulting in two distinct signatures. So, it's important to ensure serialization rules, which are defined in NIP-01, are the same across different NIP-44 implementations.
-resulting in two distinct signatures. So, it's important
-to ensure serialization rules, which are defined in NIP-01,
-are the same across different NIP-44 implementations.
 
-After serialization, the event is signed by Schnorr signature over secp256k1,
+After serialization, the event is signed by Schnorr signature over secp256k1, defined in BIP340. It's important to ensure the key and signature validity as per BIP340 rules.
-defined in BIP340. It's important to ensure the key and signature validity as
-per BIP340 rules.
 
 ## Versions
 
@@ -56,18 +50,12 @@ Currently defined encryption algorithms:
 
 The algorithm choices are justified in a following way:
 
-- Encrypt-then-mac-then-sign instead of encrypt-then-sign-then-mac:
+- Encrypt-then-mac-then-sign instead of encrypt-then-sign-then-mac: only events wrapped in NIP-01 signed envelope are currently accepted by nostr.
-  only events wrapped in NIP-01 signed envelope are currently accepted by nostr.
+- ChaCha instead of AES: it's faster and has [better security against multi-key attacks](https://datatracker.ietf.org/doc/draft-irtf-cfrg-aead-limits/)
-- ChaCha instead of AES: it's faster and has
+- ChaCha instead of XChaCha: XChaCha has not been standardized. Also, we don't need xchacha's improved collision resistance of nonces: every message has a new (key, nonce) pair.
-  [better security against multi-key attacks](https://datatracker.ietf.org/doc/draft-irtf-cfrg-aead-limits/)
+- HMAC-SHA256 instead of Poly1305: polynomial MACs are much easier to forge SHA256 instead of SHA3 or BLAKE: it is already used in nostr. Also blake's
-- ChaCha instead of XChaCha: XChaCha has not been standardized. Also, we don't need xchacha's improved
+  speed advantage is smaller in non-parallel environments - Custom padding instead of padmé: better leakage reduction for small messages
-  collision resistance of nonces: every message has a new (key, nonce) pair.
+- Base64 encoding instead of an other compression algorithm: it is widely available, and is already used in nostr
-- HMAC-SHA256 instead of Poly1305: polynomial MACs are much easier to forge
-- SHA256 instead of SHA3 or BLAKE: it is already used in nostr. Also blake's
-  speed advantage is smaller in non-parallel environments
-- Custom padding instead of padmé: better leakage reduction for small messages
-- Base64 encoding instead of an other compression algorithm: it is widely available,
-  and is already used in nostr
 
 ### Functions and operations
 
@@ -77,12 +65,7 @@ The algorithm choices are justified in a following way:
     comprised of methods `hkdf_extract(IKM, salt)` and `hkdf_expand(OKM, info, L)`
   - `chacha20(key, nonce, data)` is ChaCha20 [(RFC 8439)](https://datatracker.ietf.org/doc/html/rfc8439), with starting counter set to 0
   - `hmac_sha256(key, message)` is HMAC [(RFC 2104)](https://datatracker.ietf.org/doc/html/rfc2104)
-  - `secp256k1_ecdh(priv_a, pub_b)` is multiplication of point B by
+  - `secp256k1_ecdh(priv_a, pub_b)` is multiplication of point B by scalar a (`a ⋅ B`), defined in [BIP340](https://github.com/bitcoin/bips/blob/e918b50731397872ad2922a1b08a5a4cd1d6d546/bip-0340.mediawiki). The operation produces shared point, and we encode the shared point's 32-byte x coordinate, using method `bytes(P)` from BIP340. Private and public keys must be validated as per BIP340: pubkey must be a valid, on-curve point, and private key must be a scalar in range `[1, secp256k1_order - 1]`
-    scalar a (`a ⋅ B`), defined in
-    [BIP340](https://github.com/bitcoin/bips/blob/e918b50731397872ad2922a1b08a5a4cd1d6d546/bip-0340.mediawiki).
-    The operation produces shared point, and we encode the shared point's 32-byte x coordinate,
-    using method `bytes(P)` from BIP340. Private and public keys must be validated
-    as per BIP340: pubkey must be a valid, on-curve point, and private key must be a scalar in range `[1, secp256k1_order - 1]`
 - Operators
   - `x[i:j]`, where `x` is a byte array and `i, j <= 0`,
     returns a `(j - i)`-byte array with a copy of the `i`-th byte (inclusive) to the `j`-th byte (exclusive) of `x`
@@ -225,15 +208,11 @@ def decrypt(payload, conversation_key):
    - Validate that AAD (nonce) is 32 bytes
 7. Base64-encode (with padding) params: `concat(version, nonce, ciphertext, mac)`
 
-After encryption, it's necessary to sign it. Use NIP-01 to serialize the event,
+After encryption, it's necessary to sign it. Use NIP-01 to serialize the event, with result base64 assigned to event's `content`. Then, use NIP-01 to sign the event using schnorr signature scheme over secp256k1.
-with result base64 assigned to event's `content`. Then, use NIP-01 to sign
-the event using schnorr signature scheme over secp256k1.
 
 #### Decryption
 
-Before decryption, it's necessary to validate the message's pubkey and signature.
+Before decryption, it's necessary to validate the message's pubkey and signature. The public key must be a valid non-zero secp256k1 curve point, and signature must be valid secp256k1 schnorr signature. For exact validation rules, refer to BIP-340.
-The public key must be a valid non-zero secp256k1 curve point, and signature must be valid
-secp256k1 schnorr signature. For exact validation rules, refer to BIP-340.
 
 1. Check if first payload's character is `#`
    - `#` is an optional future-proof flag that means non-base64 encoding is used
@@ -260,11 +239,9 @@ secp256k1 schnorr signature. For exact validation rules, refer to BIP-340.
 
 ## Tests and code
 
-A collection of implementations in different languages is
+A collection of implementations in different languages is available at https://github.com/paulmillr/nip44.
-available [on GitHub](https://github.com/paulmillr/nip44).
 
-We publish extensive test vectors. Instead of having it in the
+We publish extensive test vectors. Instead of having it in the document directly, a sha256 checksum of vectors is provided:
-document directly, a sha256 checksum of vectors is provided:
 
     269ed0f69e4c192512cc779e78c555090cebc7c785b609e338a62afc3ce25040  nip44.vectors.json
 
@@ -286,11 +263,8 @@ The file also contains intermediate values. A quick guidance with regards to its
 - `valid.get_conversation_key`: calculate conversation_key from secret key sec1 and public key pub2
 - `valid.get_message_keys`: calculate chacha_key, chacha_nocne, hmac_key from conversation_key and nonce
 - `valid.calc_padded_len`: take unpadded length (first value), calculate padded length (second value)
-- `valid.encrypt_decrypt`: emulate real conversation. Calculate
+- `valid.encrypt_decrypt`: emulate real conversation. Calculate pub2 from sec2, verify conversation_key from (sec1, pub2), encrypt, verify payload, then calculate pub1 from sec1, verify conversation_key from (sec2, pub1), decrypt, verify plaintext.
-  pub2 from sec2, verify conversation_key from (sec1, pub2), encrypt, verify payload,
+- `valid.encrypt_decrypt_long_msg`: same as previous step, but instead of a full plaintext and payload, their checksum is provided.
-  then calculate pub1 from sec1, verify conversation_key from (sec2, pub1), decrypt, verify plaintext.
-- `valid.encrypt_decrypt_long_msg`: same as previous step, but instead of a full plaintext and payload,
-  their checksum is provided.
 - `invalid.encrypt_msg_lengths`
 - `invalid.get_conversation_key`: calculating converastion_key must throw an error
 - `invalid.decrypt`: decrypting message content must throw an error