initial addition of essential crypto, encoders, workflows and LLM instructions

pkg/interfaces/signer/signer.go

@@ -0,0 +1,42 @@
+// Package signer defines server for management of signatures, used to
+// abstract the signature algorithm from the usage.
+package signer
+
+// I is an interface for a key pair for signing, created to abstract between a CGO fast BIP-340
+// signature library and the slower btcec library.
+type I interface {
+	// Generate creates a fresh new key pair from system entropy, and ensures it is even (so
+	// ECDH works).
+	Generate() (err error)
+	// InitSec initialises the secret (signing) key from the raw bytes, and also
+	// derives the public key because it can.
+	InitSec(sec []byte) (err error)
+	// InitPub initializes the public (verification) key from raw bytes, this is
+	// expected to be an x-only 32 byte pubkey.
+	InitPub(pub []byte) (err error)
+	// Sec returns the secret key bytes.
+	Sec() []byte
+	// Pub returns the public key bytes (x-only schnorr pubkey).
+	Pub() []byte
+	// Sign creates a signature using the stored secret key.
+	Sign(msg []byte) (sig []byte, err error)
+	// Verify checks a message hash and signature match the stored public key.
+	Verify(msg, sig []byte) (valid bool, err error)
+	// Zero wipes the secret key to prevent memory leaks.
+	Zero()
+	// ECDH returns a shared secret derived using Elliptic Curve Diffie-Hellman on
+	// the I secret and provided pubkey.
+	ECDH(pub []byte) (secret []byte, err error)
+}
+
+// Gen is an interface for nostr BIP-340 key generation.
+type Gen interface {
+	// Generate gathers entropy and derives pubkey bytes for matching, this returns the 33 byte
+	// compressed form for checking the oddness of the Y coordinate.
+	Generate() (pubBytes []byte, err error)
+	// Negate flips the public key Y coordinate between odd and even.
+	Negate()
+	// KeyPairBytes returns the raw bytes of the secret and public key, this returns the 32 byte
+	// X-only pubkey.
+	KeyPairBytes() (secBytes, cmprPubBytes []byte)
+}