// SECURE.H - SecureString class definition

// Algorithm taken from Michiel de Bruijn, "Keep Your Data
// Under Lock and Key", in Visual Basic Programmers Journal,
// Sept. 1995.

#include <assert.h>
#include <iostream.h>
#include <string.h>

class SecureString {
public:
  SecureString(){ key[0] = '\0'; }
  // Default constructor.

  SecureString( const char * plain, const char * keyV );
  // Construct a secure string from an existing string and a key.

  void Decode( char * buffer );
  // Fill a pre-allocated buffer with the decoded string.

  void Encode( const char * plain, const char * keyV );
  // Initialize key and encode a string.

  friend ostream & operator <<( ostream & os, const SecureString & S );
  // Stream output operator.

private:
  enum { keyMax = 50, stringMax = 1000 };
  char key[keyMax+1];      // encryption key
  char data[stringMax+1];  // encrypted string
  unsigned int length;     // length of string

  void Translate( const char * inputStr,
                        char * outStr ) const;
};