1 Imports System.Collections.Generic
2 Imports System.Text
3 Imports System.IO
4 Imports System.Security.Cryptography
5 Public Class Encryption
6 Public Shared Function InverseByBase(st As String, MoveBase As Integer) As String
7 Dim SB As New StringBuilder()
8 'st = ConvertToLetterDigit(st);
9 Dim c As Integer
10 Dim i As Integer = 0
11 While i < st.Length
12 If i + MoveBase > st.Length - 1 Then
13 c = st.Length - i
14 Else
15 c = MoveBase
16 End If
17 SB.Append(InverseString(st.Substring(i, c)))
18 i += MoveBase
19 End While
20 Return SB.ToString()
21 End Function
22
23 Public Shared Function InverseString(st As String) As String
24 Dim SB As New StringBuilder()
25 For i As Integer = st.Length - 1 To 0 Step -1
26 SB.Append(st(i))
27 Next
28 Return SB.ToString()
29 End Function
30
31 Public Shared Function ConvertToLetterDigit(st As String) As String
32 Dim SB As New StringBuilder()
33 For Each ch As Char In st
34 If Char.IsLetterOrDigit(ch) = False Then
35 SB.Append(Convert.ToInt16(ch).ToString())
36 Else
37 SB.Append(ch)
38 End If
39 Next
40 Return SB.ToString()
41 End Function
42
43 ''' <summary>
44 ''' moving all characters in string insert then into new index
45 ''' </summary>
46 ''' <param name="st">string to moving characters</param>
47 ''' <returns>moved characters string</returns>
48 Public Shared Function Boring(st As String) As String
49 Dim NewPlace As Integer
50 Dim ch As Char
51 For i As Integer = 0 To st.Length - 1
52 NewPlace = i * Convert.ToUInt16(st(i))
53 NewPlace = NewPlace Mod st.Length
54 ch = st(i)
55 st = st.Remove(i, 1)
56 st = st.Insert(NewPlace, ch.ToString())
57 Next
58 Return st
59 End Function
60
61 Public Shared Function MakePassword(st As String, Identifier As String) As String
62 If Identifier.Length <> 3 Then
63 Throw New ArgumentException("Identifier must be 3 character length")
64 End If
65
66 Dim num As Integer() = New Integer(2) {}
67 num(0) = Convert.ToInt32(Identifier(0).ToString(), 10)
68 num(1) = Convert.ToInt32(Identifier(1).ToString(), 10)
69 num(2) = Convert.ToInt32(Identifier(2).ToString(), 10)
70 st = Boring(st)
71 st = InverseByBase(st, num(0))
72 st = InverseByBase(st, num(1))
73 st = InverseByBase(st, num(2))
74
75 Dim SB As New StringBuilder()
76 For Each ch As Char In st
77 SB.Append(ChangeChar(ch, num))
78 Next
79 Return SB.ToString()
80 End Function
81
82 Private Shared Function ChangeChar(ch As Char, EnCode As Integer()) As Char
83 ch = Char.ToUpper(ch)
84 If ch >= "A"c AndAlso ch <= "H"c Then
85 Return Convert.ToChar(Convert.ToInt32(ch) + 2 * EnCode(0))
86 ElseIf ch >= "I"c AndAlso ch <= "P"c Then
87 Return Convert.ToChar(Convert.ToInt32(ch) - EnCode(2))
88 ElseIf ch >= "Q"c AndAlso ch <= "Z"c Then
89 Return Convert.ToChar(Convert.ToInt32(ch) - EnCode(1))
90 ElseIf ch >= "0"c AndAlso ch <= "4"c Then
91 Return Convert.ToChar(Convert.ToInt32(ch) + 5)
92 ElseIf ch >= "5"c AndAlso ch <= "9"c Then
93 Return Convert.ToChar(Convert.ToInt32(ch) - 5)
94 Else
95 Return "0"c
96 End If
97 End Function
98 End Class
