/
read.go
68 lines (54 loc) · 1.13 KB
/
read.go
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
package main
import (
"crypto/rc4"
"github.com/andrewburian/stegoimg"
"io"
)
func read_stego(img io.Reader, secret string, out io.Writer) {
// see if encryption is used or not
var encrypt bool = false
var crypt *rc4.Cipher
if secret != "" {
encrypt = true
var err error
crypt, err = rc4.NewCipher([]byte(secret))
if err != nil {
panic(err)
}
// when the function is finished, zero the keyspace
defer crypt.Reset()
}
// get a buffer to read data from the image
buf := make([]byte, 128)
// create the stego img reader to read the data
stegoReader, err := stegoimg.NewStegoImgReader(img)
if err != nil {
panic(err)
}
// read and decrypt the data
for {
// read the new data block
n, err := stegoReader.Read(buf)
if err != nil && err != io.EOF {
panic(err)
}
// break if no data was read
if n == 0 {
break
}
// optionally decrypt
if encrypt {
crypt.XORKeyStream(buf[:n], buf[:n])
}
// write to the stego writer
_, writeErr := out.Write(buf[:n])
if writeErr != nil {
panic(writeErr)
}
// break if that's the end of the data
if err == io.EOF {
break
}
}
return
}