sign

Documentation

Overview

Package sign provides Ed25519 sign/verify primitives for zonegit commits and tags.

The commit object reserves a "signature" header (see pkg/object/commit.go). A signature is computed over the canonical commit bytes with the "signature" line stripped — exactly the way Git computes GPG signatures over commits. Re-encoding the commit with the new header lands an identical canonical payload byte-for-byte for any future verifier.

Scope of v3 (per roadmap):

• file-backed Ed25519 keypairs (no KMS yet)
• sign single commits via the CLI
• verify a single commit or the first-parent chain to the root

Out of scope here (later milestones): KMS integration, multi-sig, X.509 chains, server-side "refuse unsigned" policy.

Index

• Variables
• func GenerateKeypair(pubPath, privPath string) error
• func LoadPrivateKey(path string) (ed25519.PrivateKey, error)
• func LoadPublicKey(path string) (ed25519.PublicKey, error)
• func SignCommit(c object.Commit, priv ed25519.PrivateKey) (object.Commit, store.Hash, store.Object, error)
• func VerifyCommit(c object.Commit, pub ed25519.PublicKey) error

Variables

var (
	ErrUnsigned           = errors.New("commit has no signature")
	ErrBadSignatureFormat = errors.New("commit signature is not in ed25519:<base64> form")
	ErrSignatureMismatch  = errors.New("commit signature does not verify")
)

Sentinel errors.

Functions

func GenerateKeypair

func GenerateKeypair(pubPath, privPath string) error

GenerateKeypair generates a new Ed25519 keypair and writes the public and private keys (base64) to the given paths. The private file is chmod 0600.

func LoadPrivateKey

func LoadPrivateKey(path string) (ed25519.PrivateKey, error)

LoadPrivateKey reads a base64-encoded Ed25519 private key from path.

func LoadPublicKey

func LoadPublicKey(path string) (ed25519.PublicKey, error)

LoadPublicKey reads a base64-encoded Ed25519 public key from path.

func SignCommit

func SignCommit(c object.Commit, priv ed25519.PrivateKey) (object.Commit, store.Hash, store.Object, error)

SignCommit returns a copy of c with Signature populated. The signature covers the canonical commit bytes with the "signature" header stripped (i.e. exactly the bytes that an unsigned re-encode would produce).

The returned commit hashes differently from the unsigned version; the caller is responsible for writing the new commit object and moving the branch ref (analogous to `git commit --amend -S`).

func VerifyCommit

func VerifyCommit(c object.Commit, pub ed25519.PublicKey) error

VerifyCommit reports whether c's Signature is a valid Ed25519 signature by pub over the unsigned canonical bytes of c.

Returns:

• nil if the signature verifies
• ErrUnsigned if c.Signature is empty
• ErrBadSignatureFormat if the header does not parse
• ErrSignatureMismatch if the signature does not verify