first commit

core/core.go

@@ -0,0 +1,79 @@
+package core
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"encoding/base64"
+	"encoding/hex"
+	"fmt"
+	"net/url"
+	"regexp"
+	"strings"
+	"unicode"
+)
+
+func DecryptURLs(jk string, crypted string) ([]string, error) {
+	key, err := convertJKToKey(jk)
+	if err != nil {
+		return []string{}, err
+	}
+
+	ciphertext, err := base64.StdEncoding.DecodeString(crypted)
+	if err != nil {
+		return []string{}, err
+	}
+
+	block, err := aes.NewCipher([]byte(key))
+	if err != nil {
+		return []string{}, err
+	}
+
+	if len(ciphertext)%aes.BlockSize != 0 {
+		return []string{}, fmt.Errorf("ciphertext has invalid length")
+	}
+
+	mode := cipher.NewCBCDecrypter(block, []byte(key))
+	mode.CryptBlocks(ciphertext, ciphertext)
+
+	return ExtractURLsFromString(fmt.Sprintf("%s", ciphertext)), nil
+}
+
+func ExtractURLsFromString(s string) []string {
+	URLs := []string{}
+
+	for _, line := range strings.Split(s, "\n") {
+		line = strings.TrimSpace(line)
+
+		line = strings.Map(func(r rune) rune {
+			if unicode.IsPrint(r) {
+				return r
+			}
+			return -1
+		}, line)
+
+		parsedURL, err := url.Parse(line)
+		if err != nil || parsedURL.Scheme == "" || parsedURL.Host == "" {
+			continue
+		}
+
+		URLs = append(URLs, line)
+	}
+
+	return URLs
+}
+
+func convertJKToKey(jk string) (string, error) {
+	re := regexp.MustCompile(`return '(\d{32})'`)
+	matches := re.FindStringSubmatch(jk)
+
+	if len(matches) < 2 {
+		return "", fmt.Errorf("no key found for jk: %s", jk)
+	}
+
+	base10key, err := hex.DecodeString(matches[1])
+	if err != nil {
+		return "", fmt.Errorf("jk is invalid: %s", jk)
+	}
+
+	return fmt.Sprintf("%s", base10key), nil
+}

core/core_test.go

@@ -0,0 +1,44 @@
+package core
+
+import "testing"
+
+func TestConvertJKToKey(t *testing.T) {
+	type args struct {
+		jk string
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    string
+		wantErr bool
+	}{
+		{
+			name: "36323334313036343130323934373732",
+			args: args{
+				jk: "function f(){ return '36323334313036343130323934373732';}",
+			},
+			want:    "6234106410294772",
+			wantErr: false,
+		},
+		{
+			name: "36373434353538393131373730353833",
+			args: args{
+				jk: "function f(){ return '36373434353538393131373730353833';}",
+			},
+			want:    "6744558911770583",
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := convertJKToKey(tt.args.jk)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("convertJKToKey() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if got != tt.want {
+				t.Errorf("convertJKToKey() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}