Encode accented letters as well

did_x509/did_x509.go

@@ -5,13 +5,11 @@ import (
 	"encoding/base64"
 	"errors"
 	"fmt"
+	"github.com/nuts-foundation/go-did/did"
+	"github.com/nuts-foundation/uzi-did-x509-issuer/x509_cert"
 	"net/url"
 	"regexp"
 	"strings"
-	"unicode"
-
-	"github.com/nuts-foundation/go-did/did"
-	"github.com/nuts-foundation/uzi-did-x509-issuer/x509_cert"
 )
 
 type X509Did struct {
@@ -60,8 +58,15 @@ func CreateDid(signingCert, caCert *x509.Certificate, subjectAttributes []x509_c
 // See https://github.com/golang/go/issues/27559#issuecomment-449652574
 func PercentEncode(input string) string {
 	var encoded strings.Builder
-	for _, r := range input {
-		if unicode.IsLetter(r) || unicode.IsDigit(r) || r == '-' || r == '_' || r == '.' {
+	// Unicode characters might consist of multiple bytes, so first we encode the string using url.PathEscape (which supports multi-byte characters),
+	// then we encode the characters that weren't encoded by url.PathEscape, but need to be encoded according to the DID specification.
+	preEscaped := url.PathEscape(input)
+	encoded.Grow(len(preEscaped))
+	for _, r := range preEscaped {
+		if r == '%' ||
+			(r >= 'A' && r <= 'Z') || (r >= 'a' && r <= 'z') ||
+			(r >= '0' && r <= '9') ||
+			r == '-' || r == '.' || r == '_' {
 			encoded.WriteRune(r)
 		} else {
 			encoded.WriteString(fmt.Sprintf("%%%02X", r))

did_x509/did_x509_test.go

@@ -21,13 +21,16 @@ func TestPercentEncode(t *testing.T) {
 		{"a+b=c", "a%2Bb%3Dc"},
 		{"~!@#$%^&*()_+", "%7E%21%40%23%24%25%5E%26%2A%28%29_%2B"},
 		{"FauxCare & Co", "FauxCare%20%26%20Co"},
+		{"FåúxCaré & Có", "F%C3%A5%C3%BAxCar%C3%A9%20%26%20C%C3%B3"},
 	}
 
 	for _, test := range tests {
-		result := PercentEncode(test.input)
-		if result != test.expected {
-			t.Errorf("PercentEncode(%q) = %q; want %q", test.input, result, test.expected)
-		}
+		t.Run(test.input, func(t *testing.T) {
+			result := PercentEncode(test.input)
+			if result != test.expected {
+				t.Errorf("PercentEncode(%q) = %q; want %q", test.input, result, test.expected)
+			}
+		})
 	}
 }