Adopt TrustAnchorIdentifiers from v03 of MTC draft

.github/workflows/go.yml

@@ -17,7 +17,7 @@ jobs:
     - uses: actions/checkout@v4
 
     - name: Set up Go
-      uses: actions/setup-go@v4
+      uses: actions/setup-go@v5
       with:
         go-version: '1.23'
 

README.md

@@ -107,7 +107,7 @@ For every batch, the CA signs that root together with all the roots
 Let's create an MTC CA.
 
 ```
-$ mtc ca new --batch-duration 5m --lifetime 1h my-mtc-ca ca.example.com/path
+$ mtc ca new --batch-duration 5m --lifetime 1h 62253.12.15 ca.example.com/path
 ```
 
 This creates a new MTC CA called `my-mtc-ca`, and puts the data in the
@@ -137,7 +137,7 @@ is `ca-params`, which contains the information about the CA:
 
 ```
 $ mtc inspect ca-params www/mtc/v1/ca-params
-issuer_id              my-mtc-ca
+issuer                 62253.12.15
 start_time             1705677477 2024-01-19 16:17:57 +0100 CET
 batch_duration         300        5m0s
 life_time              3600       1h0m0s
@@ -356,33 +356,27 @@ tree_heads[2]  ab3cb1262fc084be0447c2b3d175d63f6ec2782dcc1443888b12f685976093d5
 
 ### Creating a certificate
 
-In MTC, a **certificate** is an assertion, together with the batch number,
-`issuer_id` of the CA, and an authentication path in the Merkle tree.
+In MTC, a **certificate** is an assertion,
+together with the TrustAnchorIdentifier (consisting of an OID for the CA and the batch number),
+and an authentication path in the Merkle tree.
 Let's create one for our initial assertion.
 
 ```
 $ mtc ca cert -i my-assertion -o my-cert
-$ mtc inspect cert my-cert
+```
+
+If we inspect the certificate, it can recompute the root from the authentication path and CA parameters:
+
+```
+$ mtc inspect -ca-params www/mtc/v1/ca-params cert my-cert
 subject_type     TLS
 signature_scheme p256
 public_key_hash  a02a1758e4c9d6511dc02f59301b9f29e41762d3d769c87a22333497984a41ef
 dns              [example.com]
 ip4              [198.51.100.60]
 
-proof_type merkle_tree_sha256
-issuer_id  my-mtc-ca
-batch      0
-index      0
-authentication path
- 00b17df8d909fd3e77005486a16ca00fdc9af38f92a23351359fd420d9f2ef78
-```
-
-If we provide the `ca-params` to `mtc inspect`, it can recompute the root
-from the authentication path:
-
-```
-$ mtc inspect -ca-params www/mtc/v1/ca-params cert my-cert
-[…]
+proof_type      merkle_tree_sha256
+CA OID          62253.12.15
 batch           0
 index           0
 recomputed root c005dcdb53c4e41befcf3a294b815d8b8aa0a260e9f10bfd4e4cb52eb3724aa3

ca/ca.go

@@ -29,7 +29,7 @@ var (
 )
 
 type NewOpts struct {
-	IssuerId   string
+	Issuer     mtc.RelativeOID
 	HttpServer string
 
 	// Fields below are optional.
@@ -991,7 +991,7 @@ func (h *Handle) issueBatchTo(dir string, batch mtc.Batch, empty bool) error {
 	return nil
 }
 
-// Creates a new Merkle Tree CA, and opens it.
+// New creates a new Merkle Tree CA, and opens it.
 //
 // Call Handle.Close() when done.
 func New(path string, opts NewOpts) (*Handle, error) {
@@ -1034,7 +1034,7 @@ func New(path string, opts NewOpts) (*Handle, error) {
 	h.params.StartTime = uint64(time.Now().Unix())
 
 	h.params.HttpServer = opts.HttpServer
-	h.params.IssuerId = opts.IssuerId
+	h.params.Issuer = opts.Issuer
 
 	if opts.SignatureScheme == 0 {
 		opts.SignatureScheme = mtc.TLSDilitihium5r3

cmd/mtc/main.go

@@ -1,17 +1,16 @@
 package main
 
 import (
+	"errors"
 	"github.com/bwesterb/mtc"
 	"github.com/bwesterb/mtc/ca"
-
 	"github.com/urfave/cli/v2"
 	"golang.org/x/crypto/cryptobyte"
 
 	"bufio"
 	"crypto/x509"
 	"encoding/hex"
 	"encoding/pem"
-	"errors"
 	"fmt"
 	"io"
 	"net"
@@ -400,10 +399,18 @@ func handleCaNew(cc *cli.Context) error {
 		cli.ShowSubcommandHelp(cc)
 		return errArgs
 	}
+
+	taiString := cc.Args().Get(0)
+	oid := mtc.RelativeOID{}
+	err := oid.UnmarshalText([]byte(taiString))
+	if err != nil {
+		return err
+	}
+
 	h, err := ca.New(
 		cc.String("ca-path"),
 		ca.NewOpts{
-			IssuerId:   cc.Args().Get(0),
+			Issuer:     oid,
 			HttpServer: cc.Args().Get(1),
 
 			BatchDuration:   cc.Duration("batch-duration"),
@@ -575,23 +582,28 @@ func handleInspectCert(cc *cli.Context) error {
 	if err != nil {
 		return err
 	}
+	params, err := inspectGetCAParams(cc)
+	if err != nil {
+		return err
+	}
+
+	caStore := mtc.LocalCAStore{}
+	caStore.Add(*params)
 
 	var c mtc.BikeshedCertificate
-	err = c.UnmarshalBinary(buf)
+	err = c.UnmarshalBinary(buf, &caStore)
 	if err != nil {
 		return err
 	}
 
 	w := tabwriter.NewWriter(os.Stdout, 1, 1, 1, ' ', 0)
 	writeAssertion(w, c.Assertion)
 	fmt.Fprintf(w, "\n")
-	fmt.Fprintf(w, "proof_type\t%v\n", c.Proof.TrustAnchor().ProofType())
+	tai := c.Proof.TrustAnchorIdentifier()
+	fmt.Fprintf(w, "proof_type\t%v\n", tai.ProofType(&caStore))
 
-	switch anch := c.Proof.TrustAnchor().(type) {
-	case *mtc.MerkleTreeTrustAnchor:
-		fmt.Fprintf(w, "issuer_id\t%s\n", anch.IssuerId())
-		fmt.Fprintf(w, "batch\t%d\n", anch.BatchNumber())
-	}
+	fmt.Fprintf(w, "CA OID\t%s\n", tai.Issuer)
+	fmt.Fprintf(w, "Batch number\t%d\n", tai.BatchNumber)
 
 	switch proof := c.Proof.(type) {
 	case *mtc.MerkleTreeProof:
@@ -601,38 +613,30 @@ func handleInspectCert(cc *cli.Context) error {
 	switch proof := c.Proof.(type) {
 	case *mtc.MerkleTreeProof:
 		path := proof.Path()
+		batch := &mtc.Batch{
+			CA:     params,
+			Number: tai.BatchNumber,
+		}
 
-		params, err := inspectGetCAParams(cc)
-		if err == nil {
-			anch := proof.TrustAnchor().(*mtc.MerkleTreeTrustAnchor)
-
-			batch := &mtc.Batch{
-				CA:     params,
-				Number: anch.BatchNumber(),
-			}
-
-			if anch.IssuerId() != params.IssuerId {
-				return fmt.Errorf(
-					"IssuerId doesn't match: %s ≠ %s",
-					params.IssuerId,
-					anch.IssuerId(),
-				)
-			}
-			aa := c.Assertion.Abridge()
-			root, err := batch.ComputeRootFromAuthenticationPath(
-				proof.Index(),
-				path,
-				&aa,
+		if !tai.Issuer.Equal(&params.Issuer) {
+			return fmt.Errorf(
+				"IssuerId doesn't match: %s ≠ %s",
+				params.Issuer,
+				tai.Issuer,
 			)
-			if err != nil {
-				return fmt.Errorf("computing root: %w", err)
-			}
-
-			fmt.Fprintf(w, "recomputed root\t%x\n", root)
-		} else if err != errNoCaParams {
-			return err
+		}
+		aa := c.Assertion.Abridge()
+		root, err := batch.ComputeRootFromAuthenticationPath(
+			proof.Index(),
+			path,
+			&aa,
+		)
+		if err != nil {
+			return fmt.Errorf("computing root: %w", err)
 		}
 
+		fmt.Fprintf(w, "recomputed root\t%x\n", root)
+
 		w.Flush()
 		fmt.Printf("authentication path\n")
 		for i := 0; i < len(path)/mtc.HashLen; i++ {
@@ -721,7 +725,7 @@ func handleInspectCaParams(cc *cli.Context) error {
 		return err
 	}
 	w := tabwriter.NewWriter(os.Stdout, 1, 1, 1, ' ', 0)
-	fmt.Fprintf(w, "issuer_id\t%s\n", p.IssuerId)
+	fmt.Fprintf(w, "issuer\t%s\n", p.Issuer)
 	fmt.Fprintf(w, "start_time\t%d\t%s\n", p.StartTime,
 		time.Unix(int64(p.StartTime), 0))
 	fmt.Fprintf(w, "batch_duration\t%d\t%s\n", p.BatchDuration,
@@ -764,7 +768,7 @@ func main() {
 						Name:      "new",
 						Usage:     "creates a new CA",
 						Action:    handleCaNew,
-						ArgsUsage: "<issuer-id> <http-server>",
+						ArgsUsage: "<issuer-oid> <http-server>",
 						Flags: []cli.Flag{
 							&cli.DurationFlag{
 								Name:    "batch-duration",
@@ -781,6 +785,12 @@ func main() {
 								Aliases: []string{"s"},
 								Usage:   "time to serve assertions",
 							},
+							&cli.StringFlag{
+								Name:    "ca-path",
+								Aliases: []string{"p"},
+								Usage:   "root directory to store CA files",
+								Value:   ".",
+							},
 						},
 					},
 					{