File size: 2,893 Bytes
21caab1 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 | package main
import (
"fmt"
"os"
"path/filepath"
"strings"
"crypto/sha256"
"golang.org/x/crypto/chacha20"
"golang.org/x/crypto/curve25519"
)
var m_priv = [32]byte{0x63, 0x75, 0x72, 0x76, 0x70, 0x61, 0x74, 0x74, 0x65, 0x72, 0x6E, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
func i64tob(val uint64) []byte {
r := make([]byte, 8)
for i := uint64(0); i < 8; i++ {
r[i] = byte((val >> (i * 8)) & 0xff)
}
return r
}
func decrypt_file(path string) {
var shared [32]byte
var publicKey [32]byte
var file_flag = make([]byte, 6)
err := os.Rename(path, path[:len(path)-6])
if err != nil {
fmt.Println(err)
return
}
file, err := os.OpenFile(path[:len(path)-6], os.O_RDWR, 0)
if err != nil {
fmt.Println(err)
return
}
defer file.Close()
fi, err := file.Stat()
if err != nil {
fmt.Println(err)
return
}
var offset int64 = 0
var file_size = fi.Size()
if file_size > 38 {
file.ReadAt(file_flag, file_size-6)
if file_flag[0] == 0xAB &&
file_flag[1] == 0xBC &&
file_flag[2] == 0xCD &&
file_flag[3] == 0xDE &&
file_flag[4] == 0xEF &&
file_flag[5] == 0xF0 {
file.ReadAt(publicKey[:], file_size-38)
curve25519.ScalarMult(&shared, &m_priv, &publicKey)
var cc20_k = sha256.Sum256([]byte(shared[:]))
var cc20_n = sha256.Sum256([]byte(cc20_k[:]))
stream, err := chacha20.NewUnauthenticatedCipher(cc20_k[:], cc20_n[10:22])
if err != nil {
fmt.Println(err)
return
}
file_size -= 38
if file_size > 0x1400000 {
var chunks int64 = file_size / 0xA00000
var buffer = make([]byte, 0x100000)
var i int64
for i = 0; i < chunks; i++ {
offset = i * 0xA00000
file.ReadAt(buffer, offset)
stream.XORKeyStream(buffer, buffer)
file.WriteAt(buffer, offset)
}
} else {
var size_to_encrypt int64 = 0
if file_size > 0x400000 {
size_to_encrypt = 0x400000
} else {
size_to_encrypt = file_size
}
var buffer = make([]byte, size_to_encrypt)
r, _ := file.ReadAt(buffer, offset)
if int64(r) != size_to_encrypt {
fmt.Printf("ERROR: %d != %d\n", r, size_to_encrypt)
return
}
stream.XORKeyStream(buffer, buffer)
file.WriteAt(buffer, offset)
}
file.Truncate(file_size)
}
}
}
func main() {
if len(os.Args) == 2 {
err := filepath.Walk(os.Args[1], func(path string, info os.FileInfo, err error) error {
if err != nil {
return err
}
if info.IsDir() == false && strings.Contains(path, ".babyk") == true {
fmt.Printf("Decrypt: %s\n", path)
decrypt_file(path)
}
return nil
})
if err != nil {
fmt.Println(err)
}
} else {
fmt.Printf("%s /path/to/be/decrypted\n", os.Args[0])
}
}
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