A free open source data encryption program for steemit users

Hello, everyone this is my first software sharing for Steemit Community. I developed a software (programmed in Visual Basic 8) for encrypting any text data. It’ll play a vital role on Steemit Community, because, on Steemit Platform we need a very long passphrase to be saved. It’s impossible to memorize this passphrase. And, it’s also very dangerous to write down this passphrase in the notepad. There are too many free password keepers & encryption programs, but, maximum are not open-source. My main objective is to provide such type open-source program.

I use AES Rijndael Block Cipher Encryption Algorithm to encrypt text data.

Step by Step Development :

• Open a new project in Visual Basic 8. Select “Standard EXE”. 

•  Create two text boxes & two command buttons on the form. Text1 textbox, Text2 textbox, Command1 commandbutton & Command2 commandbutton.
   

•  Change the caption of the command buttons from “Command1” to “Encrypt data” & “Command2” to “Decrypt data”.
   

•  Add a class module “CRijndael” to the project
   

•  Add this following codes to the class module “CRijndael” :
   

 ' Credits : Phil Fresle

Option Explicit
Private m_lOnBits(30) As Long
Private m_l2Power(30) As Long
Private m_bytOnBits(7) As Byte
Private m_byt2Power(7) As Byte
Private m_InCo(3) As Byte
Private m_fbsub(255) As Byte
Private m_rbsub(255) As Byte
Private m_ptab(255) As Byte
Private m_ltab(255) As Byte
Private m_ftable(255) As Long
Private m_rtable(255) As Long
Private m_rco(29) As Long
Private m_Nk As Long
Private m_Nb As Long
Private m_Nr As Long
Private m_fi(23) As Byte
Private m_ri(23) As Byte
Private m_fkey(119) As Long
Private m_rkey(119) As Long
Private Declare Sub CopyMemory Lib “kernel32” Alias “RtlMoveMemory” (ByVal Destination As Any, ByVal Source As Any, ByVal Length As Long)
Private Sub Class_Initialize()
m_InCo(0) = &HB: m_InCo(1) = &HD
m_InCo(2) = &H9: m_InCo(3) = &HE
m_bytOnBits(0) = 1 ’ 00000001
m_bytOnBits(1) = 3 ’ 00000011
m_bytOnBits(2) = 7 ’ 00000111
m_bytOnBits(3) = 15 ’ 00001111
m_bytOnBits(4) = 31 ’ 00011111
m_bytOnBits(5) = 63 ’ 00111111
m_bytOnBits(6) = 127 ’ 01111111
m_bytOnBits(7) = 255 ’ 11111111
m_byt2Power(0) = 1 ’ 00000001
m_byt2Power(1) = 2 ’ 00000010
m_byt2Power(2) = 4 ’ 00000100
m_byt2Power(3) = 8 ’ 00001000
m_byt2Power(4) = 16 ’ 00010000
m_byt2Power(5) = 32 ’ 00100000
m_byt2Power(6) = 64 ’ 01000000
m_byt2Power(7) = 128 ’ 10000000
m_lOnBits(0) = 1 ’ 00000000000000000000000000000001
m_lOnBits(1) = 3 ’ 00000000000000000000000000000011
m_lOnBits(2) = 7 ’ 00000000000000000000000000000111
m_lOnBits(3) = 15 ’ 00000000000000000000000000001111
m_lOnBits(4) = 31 ’ 00000000000000000000000000011111
m_lOnBits(5) = 63 ’ 00000000000000000000000000111111
m_lOnBits(6) = 127 ’ 00000000000000000000000001111111
m_lOnBits(7) = 255 ’ 00000000000000000000000011111111
m_lOnBits(8) = 511 ’ 00000000000000000000000111111111
m_lOnBits(9) = 1023 ’ 00000000000000000000001111111111
m_lOnBits(10) = 2047 ’ 00000000000000000000011111111111
m_lOnBits(11) = 4095 ’ 00000000000000000000111111111111
m_lOnBits(12) = 8191 ’ 00000000000000000001111111111111
m_lOnBits(13) = 16383 ’ 00000000000000000011111111111111
m_lOnBits(14) = 32767 ’ 00000000000000000111111111111111
m_lOnBits(15) = 65535 ’ 00000000000000001111111111111111
m_lOnBits(16) = 131071 ’ 00000000000000011111111111111111
m_lOnBits(17) = 262143 ’ 00000000000000111111111111111111
m_lOnBits(18) = 524287 ’ 00000000000001111111111111111111
m_lOnBits(19) = 1048575 ’ 00000000000011111111111111111111
m_lOnBits(20) = 2097151 ’ 00000000000111111111111111111111
m_lOnBits(21) = 4194303 ’ 00000000001111111111111111111111
m_lOnBits(22) = 8388607 ’ 00000000011111111111111111111111
m_lOnBits(23) = 16777215 ’ 00000000111111111111111111111111
m_lOnBits(24) = 33554431 ’ 00000001111111111111111111111111
m_lOnBits(25) = 67108863 ’ 00000011111111111111111111111111
m_lOnBits(26) = 134217727 ’ 00000111111111111111111111111111
m_lOnBits(27) = 268435455 ’ 00001111111111111111111111111111
m_lOnBits(28) = 536870911 ’ 00011111111111111111111111111111
m_lOnBits(29) = 1073741823 ’ 00111111111111111111111111111111
m_lOnBits(30) = 2147483647 ’ 01111111111111111111111111111111
m_l2Power(0) = 1 ’ 00000000000000000000000000000001
m_l2Power(1) = 2 ’ 00000000000000000000000000000010
m_l2Power(2) = 4 ’ 00000000000000000000000000000100
m_l2Power(3) = 8 ’ 00000000000000000000000000001000
m_l2Power(4) = 16 ’ 00000000000000000000000000010000
m_l2Power(5) = 32 ’ 00000000000000000000000000100000
m_l2Power(6) = 64 ’ 00000000000000000000000001000000
m_l2Power(7) = 128 ’ 00000000000000000000000010000000
m_l2Power(8) = 256 ’ 00000000000000000000000100000000
m_l2Power(9) = 512 ’ 00000000000000000000001000000000
m_l2Power(10) = 1024 ’ 00000000000000000000010000000000
m_l2Power(11) = 2048 ’ 00000000000000000000100000000000
m_l2Power(12) = 4096 ’ 00000000000000000001000000000000
m_l2Power(13) = 8192 ’ 00000000000000000010000000000000
m_l2Power(14) = 16384 ’ 00000000000000000100000000000000
m_l2Power(15) = 32768 ’ 00000000000000001000000000000000
m_l2Power(16) = 65536 ’ 00000000000000010000000000000000
m_l2Power(17) = 131072 ’ 00000000000000100000000000000000
m_l2Power(18) = 262144 ’ 00000000000001000000000000000000
m_l2Power(19) = 524288 ’ 00000000000010000000000000000000
m_l2Power(20) = 1048576 ’ 00000000000100000000000000000000
m_l2Power(21) = 2097152 ’ 00000000001000000000000000000000
m_l2Power(22) = 4194304 ’ 00000000010000000000000000000000
m_l2Power(23) = 8388608 ’ 00000000100000000000000000000000
m_l2Power(24) = 16777216 ’ 00000001000000000000000000000000
m_l2Power(25) = 33554432 ’ 00000010000000000000000000000000
m_l2Power(26) = 67108864 ’ 00000100000000000000000000000000
m_l2Power(27) = 134217728 ’ 00001000000000000000000000000000
m_l2Power(28) = 268435456 ’ 00010000000000000000000000000000
m_l2Power(29) = 536870912 ’ 00100000000000000000000000000000
m_l2Power(30) = 1073741824 ’ 01000000000000000000000000000000
End Sub
Private Function LShift(ByVal lValue As Long, ByVal iShiftBits As Integer) As Long
If iShiftBits = 0 Then
LShift = lValue: Exit Function
ElseIf iShiftBits = 31 Then
LShift = IIf(lValue And 1, &H80000000, 0)
Exit Function
ElseIf iShiftBits < 0 Or iShiftBits > 31 Then
Err.Raise 6
End If
If (lValue And m_l2Power(31 - iShiftBits)) Then
LShift = ((lValue And m_lOnBits(31 - (iShiftBits + 1))) * m_l2Power(iShiftBits)) Or &H80000000
Else
LShift = ((lValue And m_lOnBits(31 - iShiftBits)) * m_l2Power(iShiftBits))
End If
End Function
Private Function RShift(ByVal lValue As Long, ByVal iShiftBits As Integer) As Long
If iShiftBits = 0 Then
RShift = lValue: Exit Function
ElseIf iShiftBits = 31 Then
RShift = IIf(lValue And &H80000000, 1, 0)
Exit Function
ElseIf iShiftBits < 0 Or iShiftBits > 31 Then
Err.Raise 6
End If
RShift = (lValue And &H7FFFFFFE) \ m_l2Power(iShiftBits)
If (lValue And &H80000000) Then RShift = (RShift Or (&H40000000 \ m_l2Power(iShiftBits - 1)))
End Function
Private Function LShiftByte(ByVal bytValue As Byte, ByVal bytShiftBits As Byte) As Byte
If bytShiftBits = 0 Then
LShiftByte = bytValue: Exit Function
ElseIf bytShiftBits = 7 Then
LShiftByte = IIf(bytValue And 1, &H80, 0)
Exit Function
ElseIf bytShiftBits < 0 Or bytShiftBits > 7 Then
Err.Raise 6
End If
LShiftByte = ((bytValue And m_bytOnBits(7 - bytShiftBits)) * m_byt2Power(bytShiftBits))
End Function
Private Function RShiftByte(ByVal bytValue As Byte, ByVal bytShiftBits As Byte) As Byte
If bytShiftBits = 0 Then
RShiftByte = bytValue: Exit Function
ElseIf bytShiftBits = 7 Then
RShiftByte = IIf(bytValue And &H80, 1, 0)
Exit Function
ElseIf bytShiftBits < 0 Or bytShiftBits > 7 Then
Err.Raise 6
End If
RShiftByte = bytValue \ m_byt2Power(bytShiftBits)
End Function
Private Function RotateLeft(ByVal lValue As Long, ByVal iShiftBits As Integer) As Long
RotateLeft = LShift(lValue, iShiftBits) Or RShift(lValue, (32 - iShiftBits))
End Function
Private Function RotateLeftByte(ByVal bytValue As Byte, ByVal bytShiftBits As Byte) As Byte
RotateLeftByte = LShiftByte(bytValue, bytShiftBits) Or RShiftByte(bytValue, (8 - bytShiftBits))
End Function
Private Function Pack(b() As Byte) As Long
Dim lCount As Long, lTemp As Long
For lCount = 0 To 3
lTemp = b(lCount): Pack = Pack Or LShift(lTemp, (lCount * 8))
Next lCount
End Function
Private Function PackFrom(b() As Byte, ByVal k As Long) As Long
Dim lCount As Long, lTemp As Long
For lCount = 0 To 3
lTemp = b(lCount + k): PackFrom = PackFrom Or LShift(lTemp, (lCount * 8))
Next lCount
End Function
Private Sub Unpack(ByVal a As Long, b() As Byte)
b(0) = a And m_lOnBits(7)
b(1) = RShift(a, 8) And m_lOnBits(7)
b(2) = RShift(a, 16) And m_lOnBits(7)
b(3) = RShift(a, 24) And m_lOnBits(7)
End Sub
Private Sub UnpackFrom(ByVal a As Long, b() As Byte, ByVal k As Long)
b(0 + k) = a And m_lOnBits(7)
b(1 + k) = RShift(a, 8) And m_lOnBits(7)
b(2 + k) = RShift(a, 16) And m_lOnBits(7)
b(3 + k) = RShift(a, 24) And m_lOnBits(7)
End Sub
Private Function Xtime(ByVal a As Byte) As Byte
Dim b As Byte: b = IIf(a And &H80, &H1B, 0)
a = LShiftByte(a, 1): a = a Xor b: Xtime = a
End Function
Private Function Bmul(ByVal x As Byte, y As Byte) As Byte
If x <> 0 And y <> 0 Then
Bmul = m_ptab((CLng(m_ltab(x)) + CLng(m_ltab(y))) Mod 255)
Else
Bmul = 0
End If
End Function
Private Function SubByte(ByVal a As Long) As Long
Dim b(3) As Byte
Unpack a, b
b(0) = m_fbsub(b(0)): b(1) = m_fbsub(b(1))
b(2) = m_fbsub(b(2)): b(3) = m_fbsub(b(3))
SubByte = Pack(b)
End Function
Private Function Product(ByVal x As Long, ByVal y As Long) As Long
Dim xb(3) As Byte, yb(3) As Byte
Unpack x, xb: Unpack y, yb
Product = Bmul(xb(0), yb(0)) Xor Bmul(xb(1), yb(1)) Xor Bmul(xb(2), yb(2)) Xor Bmul(xb(3), yb(3))
End Function
Private Function InvMixCol(ByVal x As Long) As Long
Dim y As Long, m As Long, b(3) As Byte
m = Pack(m_InCo)
b(3) = Product(m, x): m = RotateLeft(m, 24)
b(2) = Product(m, x): m = RotateLeft(m, 24)
b(1) = Product(m, x): m = RotateLeft(m, 24)
b(0) = Product(m, x): y = Pack(b)
InvMixCol = y
End Function
Private Function ByteSub(ByVal x As Byte) As Byte
Dim y As Byte
y = m_ptab(255 - m_ltab(x)): x = y
x = RotateLeftByte(x, 1): y = y Xor x
x = RotateLeftByte(x, 1): y = y Xor x
x = RotateLeftByte(x, 1): y = y Xor x
x = RotateLeftByte(x, 1): y = y Xor x
y = y Xor &H63: ByteSub = y
End Function
Private Sub gentables()
Dim i As Long, y As Byte
Dim b(3) As Byte, ib As Byte
m_ltab(0) = 0: m_ptab(0) = 1
m_ltab(1) = 0: m_ptab(1) = 3
m_ltab(3) = 1
For i = 2 To 255
m_ptab(i) = m_ptab(i - 1) Xor Xtime(m_ptab(i - 1))
m_ltab(m_ptab(i)) = i
Next i
m_fbsub(0) = &H63: m_rbsub(&H63) = 0
For i = 1 To 255
ib = i: y = ByteSub(ib)
m_fbsub(i) = y: m_rbsub(y) = i
Next i
y = 1
For i = 0 To 29
m_rco(i) = y: y = Xtime(y)
Next i
For i = 0 To 255
y = m_fbsub(i): b(3) = y Xor Xtime(y)
b(2) = y: b(1) = y
b(0) = Xtime(y): m_ftable(i) = Pack(b)
y = m_rbsub(i): b(3) = Bmul(m_InCo(0), y)
b(2) = Bmul(m_InCo(1), y): b(1) = Bmul(m_InCo(2), y)
b(0) = Bmul(m_InCo(3), y): m_rtable(i) = Pack(b)
Next i
End Sub
Private Sub gkey(ByVal nb As Long, ByVal nk As Long, Key() As Byte)
Dim i As Long, j As Long, k As Long, m As Long
Dim N As Long, C1 As Long, C2 As Long, C3 As Long
Dim CipherKey(7) As Long
m_Nb = nb: m_Nk = nk
If m_Nb >= m_Nk Then
m_Nr = 6 + m_Nb
Else
m_Nr = 6 + m_Nk
End If
C1 = 1
If m_Nb < 8 Then
C2 = 2: C3 = 3
Else
C2 = 3: C3 = 4
End If
For j = 0 To nb - 1
m = j * 3
m_fi(m) = (j + C1) Mod nb
m_fi(m + 1) = (j + C2) Mod nb
m_fi(m + 2) = (j + C3) Mod nb
m_ri(m) = (nb + j - C1) Mod nb
m_ri(m + 1) = (nb + j - C2) Mod nb
m_ri(m + 2) = (nb + j - C3) Mod nb
Next j
N = m_Nb * (m_Nr + 1)
For i = 0 To m_Nk - 1
j = i * 4: CipherKey(i) = PackFrom(Key, j)
Next i
For i = 0 To m_Nk - 1
m_fkey(i) = CipherKey(i)
Next i
j = m_Nk: k = 0
Do While j < N
m_fkey(j) = m_fkey(j - m_Nk) Xor SubByte(RotateLeft(m_fkey(j - 1), 24)) Xor m_rco(k)
If m_Nk <= 6 Then
i = 1
Do While i < m_Nk And (i + j) < N
m_fkey(i + j) = m_fkey(i + j - m_Nk) Xor m_fkey(i + j - 1): i = i + 1
Loop
Else
i = 1
Do While i < 4 And (i + j) < N
m_fkey(i + j) = m_fkey(i + j - m_Nk) Xor m_fkey(i + j - 1): i = i + 1
Loop
If j + 4 < N Then
m_fkey(j + 4) = m_fkey(j + 4 - m_Nk) Xor SubByte(m_fkey(j + 3))
End If
i = 5
Do While i < m_Nk And (i + j) < N
m_fkey(i + j) = m_fkey(i + j - m_Nk) Xor m_fkey(i + j - 1): i = i + 1
Loop
End If
j = j + m_Nk: k = k + 1
Loop
For j = 0 To m_Nb - 1
m_rkey(j + N - nb) = m_fkey(j)
Next j
i = m_Nb
Do While i < N - m_Nb
k = N - m_Nb - i
For j = 0 To m_Nb - 1
m_rkey(k + j) = InvMixCol(m_fkey(i + j))
Next j
i = i + m_Nb
Loop
j = N - m_Nb
Do While j < N
m_rkey(j - N + m_Nb) = m_fkey(j): j = j + 1
Loop
End Sub
Private Sub Encrypt(Buff() As Byte)
Dim i As Long, j As Long, k As Long, m As Long
Dim a(7) As Long, b(7) As Long, x() As Long
Dim y() As Long, t() As Long
For i = 0 To m_Nb - 1
j = i * 4: a(i) = PackFrom(Buff, j): a(i) = a(i) Xor m_fkey(i)
Next i
k = m_Nb: x = a: y = b
For i = 1 To m_Nr - 1
For j = 0 To m_Nb - 1
m = j * 3
y(j) = m_fkey(k) Xor m_ftable(x(j) And m_lOnBits(7)) Xor RotateLeft(m_ftable(RShift(x(m_fi(m)), 8) And m_lOnBits(7)), 8) Xor RotateLeft(m_ftable(RShift(x(m_fi(m + 1)), 16) And m_lOnBits(7)), 16) Xor RotateLeft(m_ftable(RShift(x(m_fi(m + 2)), 24) And m_lOnBits(7)), 24)
k = k + 1
Next j
t = x: x = y: y = t
Next i
For j = 0 To m_Nb - 1
m = j * 3
y(j) = m_fkey(k) Xor m_fbsub(x(j) And m_lOnBits(7)) Xor RotateLeft(m_fbsub(RShift(x(m_fi(m)), 8) And m_lOnBits(7)), 8) Xor RotateLeft(m_fbsub(RShift(x(m_fi(m + 1)), 16) And m_lOnBits(7)), 16) Xor RotateLeft(m_fbsub(RShift(x(m_fi(m + 2)), 24) And m_lOnBits(7)), 24)
k = k + 1
Next j
For i = 0 To m_Nb - 1
j = i * 4: UnpackFrom y(i), Buff, j: x(i) = 0: y(i) = 0
Next i
End Sub
Private Sub Decrypt(Buff() As Byte)
Dim i As Long, j As Long, k As Long, m As Long
Dim a(7) As Long, b(7) As Long, x() As Long
Dim y() As Long, t() As Long
For i = 0 To m_Nb - 1
j = i * 4: a(i) = PackFrom(Buff, j): a(i) = a(i) Xor m_rkey(i)
Next i
k = m_Nb: x = a: y = b
For i = 1 To m_Nr - 1
For j = 0 To m_Nb - 1
m = j * 3
y(j) = m_rkey(k) Xor m_rtable(x(j) And m_lOnBits(7)) Xor RotateLeft(m_rtable(RShift(x(m_ri(m)), 8) And m_lOnBits(7)), 8) Xor RotateLeft(m_rtable(RShift(x(m_ri(m + 1)), 16) And m_lOnBits(7)), 16) Xor RotateLeft(m_rtable(RShift(x(m_ri(m + 2)), 24) And m_lOnBits(7)), 24)
k = k + 1
Next j
t = x: x = y: y = t
Next i
For j = 0 To m_Nb - 1
m = j * 3
y(j) = m_rkey(k) Xor m_rbsub(x(j) And m_lOnBits(7)) Xor RotateLeft(m_rbsub(RShift(x(m_ri(m)), 8) And m_lOnBits(7)), 8) Xor RotateLeft(m_rbsub(RShift(x(m_ri(m + 1)), 16) And m_lOnBits(7)), 16) Xor RotateLeft(m_rbsub(RShift(x(m_ri(m + 2)), 24) And m_lOnBits(7)), 24)
k = k + 1
Next j
For i = 0 To m_Nb - 1
j = i * 4: UnpackFrom y(i), Buff, j: x(i) = 0: y(i) = 0
Next i
End Sub
Private Function IsInitialized(ByRef vArray As Variant) As Boolean
On Local Error Resume Next
IsInitialized = IsNumeric(UBound(vArray))
End Function
Public Function EncryptData(bytMessage() As Byte, bytPassword() As Byte) As Byte()
Dim bytKey(31) As Byte, bytIn() As Byte, bytOut() As Byte
Dim bytTemp(31) As Byte, lCount As Long, lLength As Long
Dim lEncodedLength As Long, bytLen(3) As Byte, lPosition As Long
If Not IsInitialized(bytMessage) Then Exit Function
If Not IsInitialized(bytPassword) Then Exit Function
For lCount = 0 To UBound(bytPassword)
bytKey(lCount) = bytPassword(lCount): If lCount = 31 Then Exit For
Next lCount
gentables
gkey 8, 8, bytKey
lLength = UBound(bytMessage) + 1: lEncodedLength = lLength + 4
If lEncodedLength Mod 32 <> 0 Then lEncodedLength = lEncodedLength + 32 - (lEncodedLength Mod 32)
ReDim bytIn(lEncodedLength - 1): ReDim bytOut(lEncodedLength - 1)
CopyMemory VarPtr(bytIn(0)), VarPtr(lLength), 4
CopyMemory VarPtr(bytIn(4)), VarPtr(bytMessage(0)), lLength
For lCount = 0 To lEncodedLength - 1 Step 32
CopyMemory VarPtr(bytTemp(0)), VarPtr(bytIn(lCount)), 32
Encrypt bytTemp
CopyMemory VarPtr(bytOut(lCount)), VarPtr(bytTemp(0)), 32
Next lCount
EncryptData = bytOut
End Function
Public Function DecryptData(bytIn() As Byte, bytPassword() As Byte) As Byte()
Dim bytMessage() As Byte, bytKey(31) As Byte, bytOut() As Byte
Dim bytTemp(31) As Byte, lCount As Long, lLength As Long
Dim lEncodedLength As Long, bytLen(3) As Byte, lPosition As Long
If Not IsInitialized(bytIn) Then Exit Function
If Not IsInitialized(bytPassword) Then Exit Function
lEncodedLength = UBound(bytIn) + 1
If lEncodedLength Mod 32 <> 0 Then Exit Function
For lCount = 0 To UBound(bytPassword)
bytKey(lCount) = bytPassword(lCount): If lCount = 31 Then Exit For
Next lCount
gentables
gkey 8, 8, bytKey
ReDim bytOut(lEncodedLength - 1)
For lCount = 0 To lEncodedLength - 1 Step 32
CopyMemory VarPtr(bytTemp(0)), VarPtr(bytIn(lCount)), 32
Decrypt bytTemp
CopyMemory VarPtr(bytOut(lCount)), VarPtr(bytTemp(0)), 32
Next lCount
CopyMemory VarPtr(lLength), VarPtr(bytOut(0)), 4
If lLength > lEncodedLength - 4 Then Exit Function
ReDim bytMessage(lLength - 1)
CopyMemory VarPtr(bytMessage(0)), VarPtr(bytOut(4)), lLength
DecryptData = bytMessage
End Function 

•  Add a module “Module 1” to the project
   

•  Add this following codes to the module “Module 1” :
   

 Option Explicit '   I use AES Rijndael Block Cipher Encryption Algorithm 

Private AES_alog  As CRijndael   

Public encryption_key As String 'hexadeimal to String Conversion function
Public Function hexa_to_str(ByVal textData As String)
Dim i As Long, CryptString As String, tmpChar As String
On Local Error Resume Next
For i = 1 To Len(textData) Step 2
CryptString = CryptString & Chr$(Val("&H" & Mid$(textData, i, 2)))
Next i
hexa_to_str = CryptString
End Function 'String to hexadecimal Convertion function
Public Function str_to_hexa(ByVal textData As String)
Dim i As Long, CryptString As String, tmpAppend As String
On Local Error Resume Next
For i = 1 To Len(textData)
tmpAppend = Hex$(Asc(Mid$(textData, i, 1)))
If Len(tmpAppend) = 1 Then tmpAppend = Trim$(Str$(0)) & tmpAppend
CryptString = CryptString & tmpAppend: DoEvents
Next i
str_to_hexa = CryptString
End Function 'Encryption function with AES encryption algorithm
Public Function Encrypt_it(ByVal strMsg As String,
ByVal pKey As String) As String
Dim ByteArray() As Byte, byteKey() As Byte, CryptText() As Byte
On Local Error Resume Next
Set AES_alog = New CRijndael
ByteArray() = StrConv(strMsg, vbFromUnicode)
byteKey() = StrConv(pKey, vbFromUnicode)
CryptText() = AES_alog.EncryptData(ByteArray(), byteKey())
Set AES_alog = Nothing
Encrypt_it = StrConv(CryptText(), vbUnicode)
End Function 'Decryption function with AES encryption algorithm
Public Function Decrypt_it(ByVal strMsg As String,
ByVal pKey As String) As String
Dim ByteArray() As Byte, byteKey() As Byte, CryptText() As Byte
On Local Error Resume Next
Set AES_alog = New CRijndael
ByteArray() = StrConv(strMsg, vbFromUnicode)
byteKey() = StrConv(pKey, vbFromUnicode)
CryptText() = AES_alog.DecryptData(ByteArray(), byteKey())
Set AES_alog = Nothing
Decrypt_it = StrConv(CryptText(), vbUnicode)
End Function
 

•  Input this following code to Form1 :
   

 Private Sub Form_Load() 'don't reveal this key 

 encryption_key = "37979fa464f002d8a9bcf743f786863bc090b16864f93a5d1f4b83f9d05" ' you may set your own key End Sub 

 'Encrypt data 

Private Sub Command1_Click() 

Dim sData As String

sData = Text1.Text

sData = Encrypt_it(sData, encryption_key)

Text2.Text = str_to_hexa(sData)

End Sub

Decrypt Data

Private Sub Command2_Click()

Dim sData As String

sData = Trim$(Text1.Text)

sData = hexa_to_str(sData)

Text2.Text = Decrypt_it(sData, encryption_key)

End Sub

•  Make the exe file :
   

 Completed ! Now run the exe file :In this tutorial I’ll encrypt my steemit posting public key STM6ipnKtY59NESmg7Km5HjUuYzzRHKd8VYdLNXMyHAGUX7MnDWMh  

 After encryption I got this encrypted data 873B6CC83B0CBDC2CAC0FA1D94D4A7B9C092A6734EEC85480466DFBADCE7B8F179202D1E25AEA7FE354631E0193860ED2FB4226B162504D258A5E80FE0F5CF9D 

 You can save this data anywhere without any risk.

Now, I’ll decrypt it again – 

 Look that I successfully decrypt it by getting the text again STM6ipnKtY59NESmg7Km5HjUuYzzRHKd8VYdLNXMyHAGUX7MnDWMh 

 WARNING !!! I use an encryption key in the code.

 ‘don’t reveal this key
encryption_key = “37979fa464f002d8a9bcf743f786863bc090b16864f93a5d1f4b83f9d05” ’ you may set your own key 

 This code must be different when you make your own software. And you don’t reveal this key. If anyone gets this encryption key then your encrypted data shall be at risk. 

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