RSA Encryption

RSA Encryption

• jmckown

  Hello

  Let's open my query...Does ANYONE use ANY KIND of .net encryption on the pda Is this possible

  Please help

  
  

• antnyuk

  bump...

  Any advice

  
  

• Carl Perkins

  That would be yes and yes.

  I've a question of my own: does your code work as expected on the desktop using RSA class from System.Security.Cryptography

  
  
  

• Anton V. Tolkachev

  Hi,

  Why don't you use the binarywriter class to writer your encrypted data to the file and then decrypt it later using the binaryreader. See a sample (although this is a V1 application) here but the author uses a binaryreader and binarywriter to store the encrypted data to a file.

  http://www.eggheadcafe.com/articles/compactframeworkencryption.asp

  Thanks.

  
  

• Bob M

  do you have a specific question you would ask if there were

  
  
  

• Sanjay sagar

  Mark, Thank you for the advice. I'll try it to see if I can get it working withoug converting it to a string, but eventually I will need to get a string out of it.

  
  

• Ian Donald

  Yes, it works on the pc. I had to fiddle with some stuff because of differences in the framework. Here's my code for the pc:

  Thank you for any help!!

  public string EncryptDataString(string strInput)
  {
  string xmlString;

  xmlString = pvtstr_JustPublicKey;

  if (strInput.Length <=0)
  return null;

  //try
  //{
  xmlString = xmlString.Substring( xmlString.IndexOf( str_CreateString +"!!!" ) + 13);
  RSACryptoServiceProvider RSAProvider = new System.Security.Cryptography.RSACryptoServiceProvider();
  // RSAParameters parameters = new System.Security.Cryptography.RSAParameters();
  
  RSAProvider.FromXmlString( xmlString );
  System.Int32 numberOfBlocks =( strInput.Length / 32 ) + 1;

  System.Char[] charArray = strInput.ToCharArray();
  System.Byte[][] byteBlockArray = new byte[ numberOfBlocks ][];
  System.Int32 incrementer = 0;
  for( System.Int32 i = 1; i <= numberOfBlocks; i++ )
  {
  if( i == numberOfBlocks )
  {
  byteBlockArray[ i - 1 ] = System.Text.ASCIIEncoding.ASCII.GetBytes( charArray, incrementer, charArray.Length - incrementer );
  }
  else
  {
  byteBlockArray[ i - 1 ] = System.Text.ASCIIEncoding.ASCII.GetBytes( charArray, incrementer, 32 );
  incrementer += 32;
  }
  }
  System.String tempStorage = strInput;
  strInput = "";
  for( System.Int32 j = 0; j < byteBlockArray.Length; j++ )
  {
  strInput = strInput + System.Convert.ToBase64String( RSAProvider.Encrypt( byteBlockArray[ j ], true ) ) ;
  }
  
  return strInput;

  }

  public string DecryptDataString(string strInput)
  {
  string xmlString = pvtstr_PublicAndPrivateKey;

  InitObject();

  xmlString = xmlString.Substring( strInput.IndexOf( "</KeySize>" ) + 12 );
  
  RSACryptoServiceProvider RSAProvider = new RSACryptoServiceProvider();
  RSAParameters parameters = new RSAParameters();
  RSAProvider.FromXmlString( xmlString );
  System.String encryptedBlock = "";
  System.Collections.Queue encryptedBlocks = new System.Collections.Queue();
  
  while( strInput.Length != 0 )
  {
  encryptedBlock = strInput.Substring( 0, strInput.IndexOf( "==" ) + 2 );
  encryptedBlocks.Enqueue( encryptedBlock );
  strInput = strInput.Remove( 0, encryptedBlock.Length );

  }
  encryptedBlocks.TrimToSize();
  System.Int32 numberOfBlocks = encryptedBlocks.Count;
  for( System.Int32 i = 1; i <= numberOfBlocks; i++ )
  {
  encryptedBlock =( System.String )encryptedBlocks.Dequeue();
  strInput = strInput + System.Text.ASCIIEncoding.ASCII.GetString( RSAProvider.Decrypt( System.Convert.FromBase64String( encryptedBlock ), true ) ) ;
  }

  return strInput;
  }
  

  
  

• fastdev

  Yes. I'm trying to get it to work using the openCFNet objects and I'm having problems. I've never had any luck getting answers on their forum, so that's why I asked if anyone here had done it.

  I can encrypt data without any problems, but when I try to decrypt it I get a 'bad data' error. For proof of concept purposes, both keys are hardcoded in the project.

  Here is my code. I don't know how to format it nicely for the forum, sorry...

  Thanks!

  public string EncryptDataString(string strInput)

  {

  string xmlString;

  InitObject();

  xmlString = pvtstr_JustPublicKey;

  if (strInput.Length <=0)

  return null;

  try

  {

  xmlString = xmlString.Substring( 0);

  RSACryptoServiceProvider RSAProvider = new OpenNETCF.Security.Cryptography.RSACryptoServiceProvider();

  RSAProvider.FromXmlString( xmlString );

  System.Int32 numberOfBlocks =( strInput.Length / 32 ) + 1;

  System.Char[] charArray = strInput.ToCharArray();

  System.Byte[][] byteBlockArray = new byte[ numberOfBlocks ][];

  System.Int32 incrementer = 0;

  for( System.Int32 i = 1; i <= numberOfBlocks; i++ )

  {

  if( i == numberOfBlocks )

  {

  byteBlockArray[ i - 1 ] = System.Text.ASCIIEncoding.ASCII.GetBytes( charArray, incrementer, charArray.Length - incrementer );

  }

  else

  {

  byteBlockArray[ i - 1 ] = System.Text.ASCIIEncoding.ASCII.GetBytes( charArray, incrementer, 32 );

  incrementer += 32;

  }

  }

  System.String tempStorage = strInput;

  strInput = "";

  for( System.Int32 j = 0; j < byteBlockArray.Length; j++ )

  {

  strInput = strInput + System.Convert.ToBase64String( RSAProvider.EncryptValue( byteBlockArray[ j ]),0,byteBlockArray.Length ) ;

  }

  }

  catch(Exception ex)

  {

  string s = ex.Message;

  }

  return strInput;

  }

  public string DecryptDataString(string strInput)

  {

  string xmlString = pvtstr_PublicAndPrivateKey;

  InitObject();

  xmlString = xmlString.Substring( 0 );

  RSACryptoServiceProvider RSAProvider = new RSACryptoServiceProvider(KeySpec.KEYEXCHANGE,true);

  RSAParameters parameters = new RSAParameters();

  RSAProvider.FromXmlString( xmlString );

  System.String encryptedBlock = "";

  System.Collections.Queue encryptedBlocks = new System.Collections.Queue();

  while( strInput.Length != 0 )

  {

  encryptedBlock = strInput.Substring( 0, strInput.IndexOf( "==" ) + 2 );

  encryptedBlocks.Enqueue( encryptedBlock );

  strInput = strInput.Remove( 0, encryptedBlock.Length );

  }

  encryptedBlocks.TrimToSize();

  System.Int32 numberOfBlocks = encryptedBlocks.Count;

  for( System.Int32 i = 1; i <= numberOfBlocks; i++ )

  {

  try

  {

  encryptedBlock =( System.String )encryptedBlocks.Dequeue();

  strInput = strInput + System.Text.ASCIIEncoding.ASCII.GetString( RSAProvider.DecryptValue( System.Convert.FromBase64String( encryptedBlock )),0,encryptedBlock.Length ) ;

  }

  catch(Exception e)

  {

  MessageBox.Show(e.Message);

  }

  }

  return strInput;

  }

  
  

• PrashG

  Try keeping the encrypted data as a byte[], don't turn it into a string and back.

  
  

• Malleswar

  Mark, that was dead on. Thank you! I feel like I'm closer to a solution now.

  I can encrypt the string and convert it to a byte array. I can then decrypt the byte array. However, I must be able to decrypt a string...it's unavoidable. I have to store the string in a text file to be used later. I'm having troubles converting the encrypted string to a byte array and they byte array to a string. Do you know...or anyone...how to do this The following code does not seem to work...

  Thanks!

  Paula

  while( strInput.Length != 0 )

  {

  encryptedBlock = strInput.Substring( 0, strInput.IndexOf( "==" ) + 2 );

  encryptedBlocks.Enqueue( encryptedBlock );

  strInput = strInput.Remove( 0, encryptedBlock.Length );

  }

  encryptedBlocks.TrimToSize();

  System.Int32 numberOfBlocks = encryptedBlocks.Count;

  for( System.Int32 i = 1; i <= numberOfBlocks; i++ )

  {

  try

  {

  encryptedBlock =( System.String )encryptedBlocks.Dequeue();

  strInput = strInput + System.Text.ASCIIEncoding.ASCII.GetString( RSAProvider.DecryptValue( System.Convert.FromBase64String( encryptedBlock )),0,encryptedBlock.Length ) ;

  }

  catch(Exception e)

  {

  MessageBox.Show(e.Message);

  }

  }

  
  

• johoja

  public string EncryptDataString(string strInput)

  {

  string xmlString;

  InitObject();

  xmlString = pvtstr_JustPublicKey;

  if (strInput.Length <=0)

  return null;

  try

  {

  RSACryptoServiceProvider RSAProvider = new OpenNETCF.Security.Cryptography.RSACryptoServiceProvider();

  RSAProvider.FromXmlString( xmlString );

  System.Int32 numberOfBlocks =( strInput.Length / 32 ) + 1;

  System.Char[] charArray = strInput.ToCharArray();

  System.Byte[][] byteBlockArray = new byte[ numberOfBlocks ][];

  System.Int32 incrementer = 0;

  for( System.Int32 i = 1; i <= numberOfBlocks; i++ )

  {

  if( i == numberOfBlocks )

  {

  byteBlockArray[ i - 1 ] = System.Text.ASCIIEncoding.ASCII.GetBytes( charArray, incrementer, charArray.Length - incrementer );

  }

  else

  {

  byteBlockArray[ i - 1 ] = System.Text.ASCIIEncoding.ASCII.GetBytes( charArray, incrementer, 32 );

  incrementer += 32;

  }

  }

  System.String tempStorage = strInput;

  strInput = "";

  byte[] byte_EncryptedByte = null;

  for( System.Int32 j = 0; j < byteBlockArray.Length; j++ )

  {

  byte_EncryptedByte = RSAProvider.EncryptValue( byteBlockArray[ j ]);

  }

  //write the value to a file using binary writer

  BinaryWriter obj_Writer = new BinaryWriter(File.Open("Program Files\\PDAServAnywhere\\tmp.txt",FileMode.Create));

  obj_Writer.Write(byte_EncryptedByte);

  obj_Writer.Close();

  BinaryReader obj_Reader = new BinaryReader(File.Open("Program Files\\PDAServAnywhere\\tmp.txt",FileMode.Open,FileAccess.Read));

  obj_Reader.BaseStream.Position = 0;

  byte[] byte_ToDecryptByte = null;

  //should figure out the size later, but it works

  byte_ToDecryptByte = obj_Reader.ReadBytes(1000);

  string str_Return = DecryptDataString(byte_ToDecryptByte);

  }

  catch(Exception ex)

  {

  MessageBox.Show(ex.Message);

  }

  return str_Return;

  }

  public string DecryptDataString(byte[] strInput)

  {

  RSACryptoServiceProvider RSAProvider = new RSACryptoServiceProvider(KeySpec.KEYEXCHANGE,true);

  RSAParameters parameters = new RSAParameters();

  string xmlString = pvtstr_PublicAndPrivateKey;

  RSAProvider.FromXmlString( xmlString );

  byte[] byte_DecryptedByte = null;

  try

  {

  byte_DecryptedByte = RSAProvider.DecryptValue(strInput);

  }

  catch(Exception e)

  {

  MessageBox.Show(e.Message);

  }

  string str_Return = System.Text.ASCIIEncoding.ASCII.GetString(byte_DecryptedByte,0,byte_DecryptedByte.Length);

  return str_Return;

  }

  
  

• SWBgHz

  Mark, that worked great! It's all working.

  I'll clean up my code and post it here for anyone else who might need it.

  Thank you!!

  
  

• Studio Two

  This is not an answer...

  It should not be marked as an answer.

  
  
• RSA Encryption