Release 2.0.0

vendor/github.com/muun/libwallet/emergencykit/emergencykit.go

@@ -2,8 +2,9 @@ package emergencykit
 
 import (
 	"bytes"
-	"crypto/rand"
+	"crypto/sha256"
 	"fmt"
+	"strconv"
 	"text/template"
 	"time"
 )
@@ -11,7 +12,9 @@ import (
 // Input struct to fill the PDF
 type Input struct {
 	FirstEncryptedKey  string
+	FirstFingerprint   string
 	SecondEncryptedKey string
+	SecondFingerprint  string
 }
 
 // Output with the html as string and the verification code
@@ -20,24 +23,57 @@ type Output struct {
 	VerificationCode string
 }
 
+var spanishMonthNames = []string{
+	"Enero",
+	"Febrero",
+	"Marzo",
+	"Abril",
+	"Mayo",
+	"Junio",
+	"Julio",
+	"Agosto",
+	"Septiembre",
+	"Octubre",
+	"Noviembre",
+	"Diciembre",
+}
+
 // GenerateHTML returns the translated emergency kit html as a string along with the verification code.
 func GenerateHTML(params *Input, lang string) (*Output, error) {
-	verificationCode := randomCode(6)
+	verificationCode := generateDeterministicCode(params)
 
+	// Render output descriptors:
+	var descriptors string
+
+	if params.hasFingerprints() {
+		descriptors = GetDescriptorsHTML(&DescriptorsData{
+			FirstFingerprint:  params.FirstFingerprint,
+			SecondFingerprint: params.SecondFingerprint,
+		})
+	}
+
+	// Render page body:
 	content, err := render("EmergencyKitContent", lang, &contentData{
+		// Externally provided:
 		FirstEncryptedKey:  params.FirstEncryptedKey,
 		SecondEncryptedKey: params.SecondEncryptedKey,
-		VerificationCode:   verificationCode,
-		// Careful: do not change these format values. See this doc for more info: https://golang.org/pkg/time/#pkg-constants
-		CurrentDate: time.Now().Format("2006/01/02"), // Format date to YYYY/MM/DD
+
+		// Computed by us:
+		VerificationCode: verificationCode,
+		CurrentDate:      formatDate(time.Now(), lang),
+		Descriptors:      descriptors,
+
+		// Template pieces separated for reuse:
+		IconHelp:    iconHelp,
+		IconPadlock: iconPadlock,
 	})
 	if err != nil {
 		return nil, fmt.Errorf("failed to render EmergencyKitContent template: %w", err)
 	}
 
+	// Render complete HTML page:
 	page, err := render("EmergencyKitPage", lang, &pageData{
 		Css:     css,
-		Logo:    logo,
 		Content: content,
 	})
 	if err != nil {
@@ -50,17 +86,40 @@ func GenerateHTML(params *Input, lang string) (*Output, error) {
 	}, nil
 }
 
-func randomCode(length int) string {
-	result := make([]byte, length)
-	_, err := rand.Read(result)
-	if err != nil {
-		panic(err)
+func formatDate(t time.Time, lang string) string {
+	if lang == "en" {
+		return t.Format("January 2, 2006")
+
+	} else {
+		// Golang has no i18n facilities, so we do our own formatting.
+		year, month, day := t.Date()
+		monthName := spanishMonthNames[month-1]
+
+		return fmt.Sprintf("%d de %s, %d", day, monthName, year)
 	}
-	charset := "0123456789"
-	for i := 0; i < length; i++ {
-		result[i] = charset[int(result[i])%len(charset)]
+}
+
+func generateDeterministicCode(params *Input) string {
+	// NOTE:
+	// This function creates a stable verification code given the inputs to render the Emergency Kit. For now, the
+	// implementation relies exclusively on the SecondEncryptedKey, which is the Muun key. This is obviously not ideal,
+	// since we're both dropping part of the input and introducing the assumption that the Muun key will always be
+	// rendered second -- but it compensates for a problem with one of our clients that causes the user key serialization
+	// to be recreated each time the kit is rendered (making this deterministic approach useless).
+
+	// Create a deterministic serialization of the input:
+	inputMaterial := params.SecondEncryptedKey
+
+	// Compute a cryptographically secure hash of the material (critical, these are keys):
+	inputHash := sha256.Sum256([]byte(inputMaterial))
+
+	// Extract a verification code from the hash (doesn't matter if we discard bytes):
+	var code string
+	for _, b := range inputHash[:6] {
+		code += strconv.Itoa(int(b) % 10)
 	}
-	return string(result)
+
+	return code
 }
 
 func render(name, language string, data interface{}) (string, error) {
@@ -80,12 +139,18 @@ func getContent(name string, language string) string {
 	switch name {
 	case "EmergencyKitPage":
 		return page
+
 	case "EmergencyKitContent":
 		if language == "es" {
 			return contentES
 		}
 		return contentEN
+
 	default:
 		panic("could not find template with name: " + name)
 	}
 }
+
+func (i *Input) hasFingerprints() bool {
+	return i.FirstFingerprint != "" && i.SecondFingerprint != ""
+}