algorithm for encrypting MS word file

hi, can anybody tell me how can i encrypt Microsoft word file,i mean i should be able to obtain a cipher text of data and it should be visible to me as well, i need a algorithm for it

Using Microsoft Word, open the document that you want to Encrypt.

1. Click on the Tools menu, click the Options tab, and then click the Security tab.
   
2. Click the advanced button. From the Encryption Type menu, scroll down and chose RC4, Microsoft Enhanced RSA and AES Cryptographic Provider (Prototype). Leave the Key Length set to 128 and the Encrypt document properties check box, checked. Click OK,
   
3. Now type a password in the "Password to Open" field, click okay.
   
4. You will get another dialog box asking you to Re-Enter your password. Please re-enter your password and click ok.
   
5. Remember: It is difficult to recover a password protected or encrypted file once you have lost the password.

How to Encrypt a File

You can encrypt files only on volumes that are formatted with the NTFS file system. To encrypt a file:

1. Click Start, point to All Programs, point to Accessories, and then click Windows Explorer.
2. Locate the file that you want, right-click the file, and then click Properties.
3. On the General tab, click Advanced.
4. Under Compress or Encrypt attributes, select the Encrypt contents to secure data check box, and then click OK.
5. Click OK. If the file is located in an unencrypted folder, you receive an Encryption Warning dialog box. Use one of the following steps:
   
   • If you want to encrypt only the file, click Encrypt the file only, and then click OK.
   • If you want to encrypt the file and the folder in which it is located, click Encrypt the file and the parent folder, and then click OK.

First decide which type of encryption algorithm you want to perform -

• Symmetric or Private Key Encryption
• Assymmetric or Public Key Encryption

In Symmetric or Private Key Encryption, there is a single or a private key shared among the sender and the receiver. It is the low-level encryption since once the private key is leaked, it might affect the security of the document.

In Assymmetric or Public Key Encryption, there are two keys - one private and one public with both sender as well as receiver. The private key is private to each sender and the public key is open to all. It is the high-level encryption since with public key open to all, an unauthorised user cannot retreive or open an encrypted document.

if sone is using ms office 2007 ,how to do it then????????
by the way which public key algorithm can be used to do so??/

• Click on the Office button, select Prepare and click on Encrypt Document option.
• In the Encrypt Document dialog window type the password for your document and click OK.
• Type the password again for verification and click OK.
• When you want to open the document it will be automatically asked for the password.

Note: By default Microsoft Office Word 2007 will save your document with 128-bit encryption.

the can be done!!! but do any body know how its done using a standalone algorithm e.g private key or public key encryption algorithm like RSA