Aplikasi Kriptografi Menggunakan Visual Basic 6

Aplikasi Kriptografi Menggunakan Menggunakan Visual Basic 6.0

Kode Listing Program : Sub dekrip() On Error Resume Next Text1.Text = "" a = Len(chiper.Text) c=1 For i = 1 To a b = Asc(Mid(UCase(hasil.Tex Asc(Mid(UCase(hasil.Text), t), i, 1)) If b > 64 And b < 123 Then If c > Len(kunci.Text) Len(kunci.Text) Then Do c=c-1 Loop Until c = 1

Else End If  d = Asc(Mid(UCase(kunci.Text), c, 1)) e = b - (d - 65) If e < 65 Then g = 91 - (65 - e) Else g=e End If  f = Chr(g) c=c+1 Else f = Chr(b) End If  Text1.Text = Text1.Text + f  If LCase(hasil.Text) = hasil.Text Then Text1.Text = LCase(Text1.Text) Else End If  Next i

End Sub Private Sub Command1_Click() On Error Resume Next hasil.Text = "" a = Len(chiper.Text) c=1 For i = 1 To a

b = Asc(Mid(UCase(chiper.Text), i, 1)) If b > 64 And b < 123 Then If c > Len(kunci.Text) Then Do c=c-1 Loop Until c = 1 Else End If  d = Asc(Mid(UCase(kunci.Text), c, 1)) e = b - (d - 65) If e < 65 Then g = 91 - (65 - e) Else g=e End If  f = Chr(g) c=c+1 Else f = Chr(b) End If  hasil.Text = hasil.Text + f  If LCase(chiper.Text) = chiper.Text Then Text1.Text = LCase(Text1.Text) Else End If  Next i End Sub

Private Sub Command2_Click() On Error Resume Next hasil.Text = "" a = Len(chiper.Text) c=1 For i = 1 To a b = Asc(Mid(UCase(chiper.Text), i, 1)) If b > 64 And b < 123 Then If c > Len(kunci.Text) Then Do c=c-1 Loop Until c = 1 Else End If  d = Asc(Mid(UCase(kunci.Text), c, 1)) e = b + (d - 65) If e > 90 Then g = 65 + (e - 91) Else g=e End If  f = Chr(g) c=c+1 Else f = Chr(b) End If  hasil.Text = hasil.Text + f  If LCase(chiper.Text) = chiper.Text Then

hasil.Text = LCase(hasil.Text) Else End If  Next i Call dekrip End Sub Private Sub Command3_Click() hasil.Text = "" kunci.Text = "" chiper.Text = "" End Sub

Private Sub Command4_Click() End End Sub

Textbox untuk PLAINTEXT namenya adalah txtplain Textbox untuk KUNCI namenya adalah txtkunci Textbox untuk CIPHER namenya adalah txtcipher  Tombol Enkrisi namenya adalah cmdEnkripsi Adodc1 namenya adalah Adovigenere Sedangkan untuk Source codenya adalah Private Sub cmdEnkripsi_Click() panjangplain = Len(Trim(txtplain.Text)) j=1 For I = 1 To panjangplain kar = Mid(txtplain.Text, I, 1) IndexAscii = Asc(kar) – 64 panjangkunci = Len(Trim(txtkunci.Text)) If kar = ” ” Then data= ” “ j=j–1 Else karkunci = Mid(txtkunci.Text, j, 1) Adovigenere.RecordSource = “select * from tblvigenere where kunci = ‘” + karkunci + “‘” Adovigenere.Refresh data = Adovigenere.Recordset.Fields(IndexAscii) End If  If j = panjangkunci Then

j=1 Else j=j+1 End If  sandi = sandi +data Next I txtcipher.Text = sandi End Sub Private Sub txtkunci_KeyPress(KeyAscii As Integer) KeyAscii = Asc(UCase(Chr(KeyAscii))) End Sub Private Sub txtplain_KeyPress(KeyAscii As Integer) KeyAscii = Asc(UCase(Chr(KeyAscii))) End Sub Sehingga jika dirun hasilnya seperti berikut :

1 # include 02 # include 03 # include 04 05 int main(){ 06 07

char keyword[100]; char msg[100];

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int crypted;

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int real_difference;

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int i, k, l;

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printf("Masukkan keyword : "); gets(keyword);

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printf("Masukkan message yang ingin di enkripsi : ");

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gets(msg);

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k = strlen(keyword); l = strlen(msg);

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while(k < l){ keyword = keyword + keyword; k = strlen(keyword); }

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printf("\n\n"); for ( i = 0; i <= strlen(msg); i++){ keyword[i] -= 'a' - 1; if ( (msg[i] + keyword[i]) > 'z'){

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crypted = 'a' + (keyword[i] + msg[i] - 'z') - 1;

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}

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else if(msg[i] == 32){ crypted = msg[i];

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}

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else {

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crypted = msg[i] + keyword[i];

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}

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printf("%c", crypted);

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if ( i >= strlen(msg))break;

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}

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return 0; getch();

44 }