Ciao,<\/p>\n
di seguito il codice C# per l’estensione del componente TextBox al fine di mitigare il problema dei “keyLogger”.<\/p>\n
Il codice \u00e8 funzionante anche se sicuramente prototipale.<\/p>\n
Spero possa esservi utile.<\/p>\n
(Codice presso GitHub: https:\/\/github.com\/waltzie\/CSharp-PasswordTextBox<\/a>)<\/p>\n using System; \/\/\/ \/\/ Problema con i caratteri [] gestiti da sendkey public class PasswordTextBox : System.Windows.Forms.TextBox private string junk = “”; private static readonly Random random = new Random(); public PasswordTextBox() { protected override void OnMouseDown(MouseEventArgs e) \/\/\/ \/\/\/ The AllowedChars gets\/sets the value of the string field, _allowedchars. \/\/\/ \/\/\/ The Obfuscate gets\/sets the value of the bool field, _obfuscate. \/\/\/ \/\/\/ The ClearText gets the value of the de-obfuscated string field, Text. private bool IsAllowedChar(char c) private string Randomchar() private string junkGenerator() private char obfuscate(char s) { Ciao, di seguito il codice C# per l’estensione del componente TextBox al fine di mitigare il problema dei “keyLogger”. Il codice \u00e8 funzionante anche se sicuramente prototipale. Spero possa esservi utile. (Codice presso GitHub: https:\/\/github.com\/waltzie\/CSharp-PasswordTextBox) using System; using System.ComponentModel; using System.Linq; using System.Windows.Forms; namespace WaltZie.Windows.Forms { \/\/\/ \/\/\/ Estensione della casella TextBox per gestire le … Continua la lettura di C# Password TextBox<\/span>
\nusing System.ComponentModel;
\nusing System.Linq;
\nusing System.Windows.Forms;
\nnamespace WaltZie.Windows.Forms
\n{<\/p>\n
\n\/\/\/ Estensione della casella TextBox per gestire le password in modo che non possano essere intercettate dai keylkoggers
\n\/\/\/<\/p>\n
\n\/\/ Problema con digitazione caratteri in contemporanea. Occorre reindirizzare OnKeyPress a thread sequenziali.<\/p>\n
\n{
\npublic static PasswordTextBox Instance = new PasswordTextBox();<\/p>\n
\nprivate uint _junkMax = 4;
\nprivate uint _junkMin = 2;
\nprivate byte _minchar = 32;
\nprivate byte _maxchar = 126;
\nprivate string _allowedchars=””;
\nprivate string _scramble;
\nprivate bool _obfuscate = false;<\/p>\n
\nprivate static readonly object syncLock = new object();
\nprivate delegate string del(string s);<\/p>\n
\n}<\/p>\n
\n{
\nif (String.IsNullOrEmpty(this.Text))
\n{
\nsendJunkChars();
\n}
\nbase.OnMouseDown(e);
\n}<\/p>\n
\n\/\/\/
\nThe AllowedChars represents characters allowed.<\/p>\n
\n\/\/\/
\n[Category(“Extensions”), Browsable(true), Description(“String containig allowed chars”)]
\npublic string AllowedChars
\n{
\nset
\n{
\nif ((value.Length) < 256) { this._allowedchars = value; this._scramble = new string(_allowedchars.ToCharArray().OrderBy(x => Guid.NewGuid()).ToArray());
\n}
\n}
\nget
\n{
\nreturn this._allowedchars;
\n}
\n}<\/p>\n
\n\/\/\/
\nThe Obfuscate define if typed text must be obfuscate with shuffled allowd chars.<\/p>\n
\n\/\/\/
\n[Category(“Extensions”), Browsable(true), Description(“Obfuscate input data”)]
\npublic bool Obfuscate
\n{
\nset
\n{
\nthis._obfuscate = value;
\nif (this._obfuscate && _allowedchars == “”) this.AllowedChars = ” !\\”#$%&'()*+-.\/0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\\\]^_`abcdefghijklmnopqrstuvwxyz{|}~”;
\n}
\nget
\n{
\nreturn this._obfuscate;
\n}
\n}<\/p>\n
\n\/\/\/
\nThe ClearText represents real typed test.<\/p>\n
\n\/\/\/ Returns original de-obfuscated typed text.
\n\/\/\/
\n[Category(“Extensions”), Browsable(true), Description(“Clear text”)]
\npublic string ClearText
\n{
\nget
\n{
\nreturn deobfuscate(this.Text);
\n}
\n}<\/p>\n
\n{
\nif (char.IsControl(c)) return false;
\nif (this._allowedchars.Length > 0)
\n{
\nif (this._allowedchars.Contains(c.ToString())) return true;
\nelse return false;
\n}
\nelse return true;
\n}<\/p>\n
\n{
\nreturn Convert.ToChar(random.Next(this._minchar, this._maxchar)).ToString();
\n}<\/p>\n
\n{
\nstring randomString = “”;
\nfor (int i = 0; i < random.Next((int)this._junkMin, (int)this._junkMax); i++)
\nrandomString += Randomchar();
\nreturn randomString;
\n}
\nprivate void sendJunkChars()
\n{
\nstring outchar = “”;
\nlock (syncLock)
\n{
\nthis.junk += junkGenerator();
\nfor (int i = 0; i < this.junk.Length; i++)
\nif (“+^%~(){}”.Contains(this.junk[i])) outchar += “{” + this.junk[i] + “}”;
\nelse outchar += this.junk[i].ToString();
\nthis.Focus();
\nSendKeys.Send(outchar);
\n}
\n}<\/p>\n
\nlock (syncLock)
\n{
\nif (this._obfuscate) return this._scramble[this._allowedchars.IndexOf(s)];
\nelse return s;
\n}
\n}
\nprivate string deobfuscate(string s) {
\nif (!this._obfuscate) return s;
\nstring outstr = “”;
\nfor (int i=0; i<this.Text.Length;i++) { outstr += this._allowedchars[this._scramble.IndexOf(this.Text[i])].ToString(); } return outstr; } protected override bool ProcessCmdKey(ref Message msg, Keys keyData) { if (this.junk.Length == 0) { if (keyData == Keys.Delete) OnKeyPress(new KeyPressEventArgs((Char)Keys.Back)); } return base.ProcessCmdKey(ref msg, keyData); } protected override void OnKeyPress(KeyPressEventArgs e) { \/\/ Controllare this.SelectedText base.OnKeyPress(e); string keyInput = e.KeyChar.ToString(); if (this.junk.Length > 0)
\n{
\n\/\/this char is junk
\ne.Handled = true;
\nlock(syncLock) this.junk = this.junk.Remove(this.junk.Length – 1);
\n}
\nelse if (IsAllowedChar(e.KeyChar))
\n{
\ne.KeyChar = obfuscate(e.KeyChar);
\nsendJunkChars();
\n}
\nelse if (e.KeyChar == ‘\\b’)
\n{
\ntry
\n{
\n\/\/ Backspace key is OK
\nsendJunkChars();
\n}
\ncatch { e.Handled = true; }
\n}
\nelse
\n{
\n\/\/ Consume this invalid key and beep
\ne.Handled = true;
\nSystem.Media.SystemSounds.Exclamation.Play();
\n}
\n}
\n}
\n}<\/p>\n","protected":false},"excerpt":{"rendered":"