feature/1114 implement account interface (#1167)

- **refactor: move session-related code to middleware package**
- **refactor: update PKL build process and adjust related
configurations**
- **feat: integrate base.cosmos.v1 Genesis module**
- **refactor: pass session context to modal rendering functions**
- **refactor: move nebula package to app directory and update templ
version**
- **refactor: Move home section video view to dedicated directory**
- **refactor: remove unused views file**
- **refactor: move styles and UI components to global scope**
- **refactor: Rename images.go to cdn.go**
- **feat: Add Empty State Illustrations**
- **refactor: Consolidate Vault Index Logic**
- **fix: References to App.wasm and remove Vault Directory embedded CDN
files**
- **refactor: Move CDN types to Models**
- **fix: Correct line numbers in templ error messages for
arch_templ.go**
- **refactor: use common types for peer roles**
- **refactor: move common types and ORM to a shared package**
- **fix: Config import dwn**
- **refactor: move nebula directory to app**
- **feat: Rebuild nebula**
- **fix: correct file paths in panels templates**
- **feat: Remove duplicate types**
- **refactor: Move dwn to pkg/core**
- **refactor: Binary Structure**
- **feat: Introduce Crypto Pkg**
- **fix: Broken Process Start**
- **feat: Update pkg/* structure**
- **feat: Refactor PKL Structure**
- **build: update pkl build process**
- **chore: Remove Empty Files**
- **refactor: remove unused macaroon package**
- **feat: Add WebAwesome Components**
- **refactor: consolidate build and generation tasks into a single
taskfile, remove redundant makefile targets**
- **refactor: refactor server and move components to pkg/core/dwn**
- **build: update go modules**
- **refactor: move gateway logic into dedicated hway command**
- **feat: Add KSS (Krawczyk-Song-Song) MPC cryptography module**
- **feat: Implement MPC-based JWT signing and UCAN token generation**
- **feat: add support for MPC-based JWT signing**
- **feat: Implement MPC-based UCAN capabilities for smart accounts**
- **feat: add address field to keyshareSource**
- **feat: Add comprehensive MPC test suite for keyshares, UCAN tokens,
and token attenuations**
- **refactor: improve MPC keyshare management and signing process**
- **feat: enhance MPC capability hierarchy documentation**
- **refactor: rename GenerateKeyshares function to NewKeyshareSource for
clarity**
- **refactor: remove unused Ethereum address computation**
- **feat: Add HasHandle and IsAuthenticated methods to HTTPContext**
- **refactor: Add context.Context support to session HTTPContext**
- **refactor: Resolve context interface conflicts in HTTPContext**
- **feat: Add session ID context key and helper functions**
- **feat: Update WebApp Page Rendering**
- **refactor: Simplify context management by using single HTTPContext
key**
- **refactor: Simplify HTTPContext creation and context management in
session middleware**
- **refactor: refactor session middleware to use a single data
structure**
- **refactor: Simplify HTTPContext implementation and session data
handling**
- **refactor: Improve session context handling and prevent nil pointer
errors**
- **refactor: Improve session context handling with nil safety and type
support**
- **refactor: improve session data injection**
- **feat: add full-screen modal component and update registration flow**
- **chore: add .air.toml to .gitignore**
- **feat: add Air to devbox and update dependencies**

pkg/crypto/mpc/jwt.go

@@ -0,0 +1,97 @@
+package mpc
+
+import (
+	"crypto/sha256"
+	"encoding/base64"
+	"fmt"
+
+	"github.com/golang-jwt/jwt"
+)
+
+// MPCSigningMethod implements the SigningMethod interface for MPC-based signing
+type MPCSigningMethod struct {
+	Name string
+	ks   keyshareSource
+}
+
+// newMPCSigningMethod creates a new MPC signing method with the given keyshare source
+func newMPCSigningMethod(name string, ks keyshareSource) *MPCSigningMethod {
+	return &MPCSigningMethod{
+		Name: name,
+		ks:   ks,
+	}
+}
+
+// Alg returns the signing method's name
+func (m *MPCSigningMethod) Alg() string {
+	return m.Name
+}
+
+// Verify verifies the signature using the MPC public key
+func (m *MPCSigningMethod) Verify(signingString, signature string, key interface{}) error {
+	// Decode the signature
+	sig, err := base64.RawURLEncoding.DecodeString(signature)
+	if err != nil {
+		return err
+	}
+
+	// Hash the signing string
+	hasher := sha256.New()
+	hasher.Write([]byte(signingString))
+	digest := hasher.Sum(nil)
+
+	// Verify using the keyshare's public key
+	valid, err := VerifySignature(m.ks.valShare.PublicKey, digest, sig)
+	if err != nil {
+		return fmt.Errorf("failed to verify signature: %w", err)
+	}
+	if !valid {
+		return fmt.Errorf("invalid signature")
+	}
+
+	return nil
+}
+
+// Sign signs the data using MPC
+func (m *MPCSigningMethod) Sign(signingString string, key interface{}) (string, error) {
+	// Hash the signing string
+	hasher := sha256.New()
+	hasher.Write([]byte(signingString))
+	digest := hasher.Sum(nil)
+
+	// Create signing functions
+	signFunc, err := m.ks.userShare.SignFunc(digest)
+	if err != nil {
+		return "", fmt.Errorf("failed to create sign function: %w", err)
+	}
+
+	valSignFunc, err := m.ks.valShare.SignFunc(digest)
+	if err != nil {
+		return "", fmt.Errorf("failed to create validator sign function: %w", err)
+	}
+
+	// Run the signing protocol
+	sig, err := RunSignProtocol(valSignFunc, signFunc)
+	if err != nil {
+		return "", fmt.Errorf("failed to run sign protocol: %w", err)
+	}
+
+	// Serialize the signature
+	sigBytes, err := SerializeSignature(sig)
+	if err != nil {
+		return "", fmt.Errorf("failed to serialize signature: %w", err)
+	}
+
+	// Encode the signature
+	encoded := base64.RawURLEncoding.EncodeToString(sigBytes)
+	return encoded, nil
+}
+
+func init() {
+	// Register the MPC signing method
+	jwt.RegisterSigningMethod("MPC256", func() jwt.SigningMethod {
+		return &MPCSigningMethod{
+			Name: "MPC256",
+		}
+	})
+}