blob: 1e82b0ebd9e86e11df2668184c29f0b4ab427ad1 (
plain)
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
|
package otp;
public class LinReg {
private int config;
private int status;
public static final int bitMask = 0xff;
public static final int bitLength = 8;
public LinReg (int config, int init)
{
this.config = 0;
this.status = 0;
this.config = config & bitMask;
this.status = init & bitMask;
//printOut();
}
public int getNextKeyBit()
{
return this.getNextBit();
}
public int getNextKey()
{
int ret=0;
int newBit;
for (int i=7;i>=0;i--)
{
newBit = getNextBit();
//System.out.println(i+". key bit is: "+Integer.toBinaryString(newBit));
ret += ( newBit << i);
//System.out.println("act key is: "+LinReg.to8BitString(ret));
}
//System.out.println("New key is: "+LinReg.to8BitString(ret));
return ret & bitMask;
}
private int getNextBit()
{
//printOut();
int ret=0;
//boolean tmp=false;
int cnt=0;
// left shift status to get next bit at bitLength + 1;
this.status = this.status << 1;
//System.out.println("Left shifted status: "+Integer.toBinaryString(this.status));
// get bit at bitLength + 1;
ret = this.status & (~bitMask);
//System.out.println("key bit unshifted is: "+Integer.toBinaryString(ret));
ret >>= bitLength;
//System.out.println("New key bit is: "+Integer.toBinaryString(ret));
// calculate next bit from status and config
for (int i = 7; i >= 0; i--)
{
// test if actual status and config bit are
// set at position i
//if ( (this.status & i) && (this.config & i) )
int statusBit = ((this.status & (1<<i) ) >> i);
int configBit = ((this.config & (1<<i) ) >> i);
//System.out.println("Bit in Status: "+Integer.toBinaryString(statusBit));
//System.out.println("Bit in Config: "+Integer.toBinaryString(configBit));
if ( (statusBit & configBit) == 1 )
{
//System.out.println("Bit "+i+" is set in C and S");
//tmp=!tmp;
cnt++;
}
}
if ( (cnt%2) == 1 )
{
this.status |= 1;
//System.out.println("Appending 1 to status");
}
else
{
//System.out.println("Appending 0 to status");
}
this.status &= bitMask;
//printOut();
return ret;
}
public void printOut()
{
System.out.println("Config is: "+to8BitString(this.config));
System.out.println("Status is: "+to8BitString(this.status));
}
public static final String to8BitString(int input)
{
String res = Integer.toBinaryString(input);
for (int i = res.length();i<bitLength;i++)
{
res="0"+res;
}
return res;
}
}
|
