''' <summary>Determines if a password is sufficiently complex.</summary> ''' <param name="pwd">Password to validate</param> ''' <param name="minLength">Minimum number of password characters.</param> ''' <param name="numUpper">Minimum number of uppercase characters.</param> ''' <param name="numLower">Minimum number of lowercase characters.</param> ''' <param name="numNumbers">Minimum number of numeric characters.</param> ''' <param name="numSpecial">Minimum number of special characters.</param> ''' <returns>True if the password is sufficiently complex.</returns> Function ValidatePassword(ByVal pwd As String, _ Optional ByVal minLength As Integer = 8, _ Optional ByVal numUpper As Integer = 2, _ Optional ByVal numLower As Integer = 2, _ Optional ByVal numNumbers As Integer = 2, _ Optional ByVal numSpecial As Integer = 2) _ As Boolean ' Replace [A-Z] with \p{Lu}, to allow for Unicode uppercase letters. Dim upper As New System.Text.RegularExpressions.Regex("[A-Z]") Dim lower As New System.Text.RegularExpressions.Regex("[a-z]") Dim number As New System.Text.RegularExpressions.Regex("[0-9]") ' Special is "none of the above". Dim special As New System.Text.RegularExpressions.Regex("[^a-zA-Z0-9]") ' Check the length. If Len(pwd) < minLength Then Return False ' Check for minimum number of occurrences. If upper.Matches(pwd).Count < numUpper Then Return False If lower.Matches(pwd).Count < numLower Then Return False If number.Matches(pwd).Count < numNumbers Then Return False If special.Matches(pwd).Count < numSpecial Then Return False ' Passed all checks. Return True End Function Sub TestValidatePassword() Dim password As String = "Password" ' Demonstrate that "Password" is not complex. MsgBox(password & " is complex: " & ValidatePassword(password)) password = "Z9f%a>2kQ" ' Demonstrate that "Z9f%a>2kQ" is not complex. MsgBox(password & " is complex: " & ValidatePassword(password)) End Sub