func edit(ct []byte, offset int, text []byte) {
block, err := aes.NewCipher(key)
if err != nil {
fmt.Println(err)
}
t := make([]byte, len(ct))
util.CTREncrypt(block, nonce, t, ct)
for i := offset; i < offset+len(text) && i < len(t); i++ {
t[i] = text[i-offset]
}
util.CTREncrypt(block, nonce, ct, t)
}
func main() {
encoded := util.ReadFile("25.txt")
bytes, err := base64.StdEncoding.DecodeString(string(encoded))
if err != nil {
log.Fatal(err)
}
oldAes, err := aes.NewCipher([]byte("YELLOW SUBMARINE"))
if err != nil {
log.Fatal(err)
}
util.ECBDecrypt(oldAes, bytes, bytes)
// we have plaintext in bytes
// encrypt it in CTR mode
block, err := aes.NewCipher(key)
if err != nil {
log.Fatal(err)
}
util.CTREncrypt(block, nonce, bytes, bytes)
// save the copy
ct := make([]byte, len(bytes))
copy(ct, bytes)
// let's prepare sequence of 0 bytes and replace the text with it
zeroes := make([]byte, len(bytes))
edit(bytes, 0, zeroes)
// result in bytes contains the key
// let's recover the original plain text:
for i := 0; i < len(ct); i++ {
bytes[i] = ct[i] ^ bytes[i]
}
fmt.Println(string(bytes))
}
func isAdmin(ct []byte) bool {
block, _ := aes.NewCipher(key)
res := make([]byte, len(ct))
copy(res, ct)
util.CTREncrypt(block, nonce, res, res)
fmt.Println("isAdmin peek:", string(res))
return bytes.Count(res, []byte(";admin=true;")) > 0
}
func init() {
scan := bufio.NewScanner(os.Stdin)
block, _ := aes.NewCipher(key)
for scan.Scan() {
t, _ := base64.StdEncoding.DecodeString(scan.Text())
util.CTREncrypt(block, nonce, t, t)
fmt.Println(len(t), hex.EncodeToString(t))
cts = append(cts, t)
}
fmt.Println("ciphertexts:", len(cts))
}
func crypt(userdata []byte) []byte {
res := bytes.Replace(userdata, []byte("="), []byte("%3D"), -1)
res = bytes.Replace(res, []byte(";"), []byte("%3B"), -1)
res = append(prefix, res...)
res = append(res, postfix...)
block, _ := aes.NewCipher(key)
res = util.PadTo(res, 16)
fmt.Println("crypt peek:", string(res))
util.CTREncrypt(block, nonce, res, res)
return res
}
func init() {
scan := bufio.NewScanner(os.Stdin)
block, _ := aes.NewCipher(key)
minLen = 999999
for scan.Scan() {
t, _ := base64.StdEncoding.DecodeString(scan.Text())
util.CTREncrypt(block, nonce, t, t)
if len(t) < minLen {
minLen = len(t)
}
cts = append(cts, t)
}
}
func main() {
s, _ := base64.StdEncoding.DecodeString("L77na/nrFsKvynd6HzOoG7GHTLXsTVu9qvY/2syLXzhPweyyMTJULu/6/kXX0KSvoOLSFQ==")
block, _ := aes.NewCipher([]byte("YELLOW SUBMARINE"))
util.CTREncrypt(block, make([]byte, 16), s, s)
fmt.Println(string(s))
}
