Program Encryption Decryption Java' title='Program Encryption Decryption Java' />PGP Encryption using Bouncy Castle. It cant be that hard. So given a couple hours of hacking with the library, heres a fully illustrated example that shows how to encrypt a file using the Bouncy Castle Cryptography API and PGP. First, giving credit where credit is due, the example comes mostly from the Key. Based. File. Processor example that ships with the Bouncy Castle PGP libraries. You can find it in the srcorgbouncycastleopenpgpexamples directory if you download the source. Ive simply unpacked the example a little, providing some pretty pictures and explanation of what the various pieces are. As in any example, you need to have downloaded a couple libraries in this case you need to visit http www. Add those to your project, as in this example, simply make sure to add them to the classpath when running the example from the command line. Program Encryption Decryption Java' title='Program Encryption Decryption Java' />Next, while you dont need to have PGP installed, you do need to have a at least one public keyring file available on your system. Im using PGP 6. 5. Windows which automatically saves my public keyring for me. You can find the location of the keyring file by Edit Options Files from within the PGP Keys window. You should see something like this Note the location of the Public Keyring File. Second, youll need to generate a keypair if you dont already have one. I wont go into the how or why I assume you know the how and why but you do need to make sure that you create what the Bouncy Castle folks call a RSA key or El Gamal key source rather than a DSA key. If you try to use a DSA keypair which Im assuming is synonomous with Diffie HellmanDSS, that I ran into org. PGPException Cant use DSA for encryption, which again is explained by the link above. Now that you downloaded the appropriate libraries, created an RSA keypair and located your public keyring file, were ready to start. Open up your favorite Java IDE Im using Eclipse and start by importing the appropriate libraries import java. I took a shortcut above and didnt specify exactly what classes I wanted to import for clarity, if youre using Eclipse you can easily clean that up by selecting Source Organize Imports or by downloading the source code at the end of this example. Ive recently been asked to write some code to decrypt some data using C which was originally encrypted in Java. While I managed to get this to work, I had to. Types Symmetric key Private key. In symmetrickey schemes, the encryption and decryption keys are the same. Communicating parties must have the same key before they. Related Resources. The Royal Institution UK and Microsoft Research together have produced activities in encryption, cryptography, and zero knowledge protocols for the. LN4jJ_U/maxresdefault.jpg' alt='Program Encryption Decryption Java' title='Program Encryption Decryption Java' />Next the class declaration and the standard public static void main etc. The Key. Based. File. Processor example on the Bouncy. Castle website lets you pass in the location of the public keyring and the file you want to encrypt, Im hardcoding it in my code so that its crystal clear what everything is the keyring that holds the public key were encrypting with. String public. Key. File. Path C pgp. Provider method of the java. Security class Security. Providernew Bouncy. Castle. Provider Next I chose to create a temporary file to hold the message that I want to encrypt File outputfile File. Temp. Filepgp, null File. Writer writer new File. Writeroutputfile writer. I want to encrypt. Char. Array writer. Read the public keyring file into a File. Advanced java interview questions Can we compare String using equality operator operatorWhat is intern method in JavaWhen is class garbage collectedWhat. Freeware Files. com Download free Encryption and Decryption software programs. This section provides a tutorial example on how to use SHA1 message digest algorithm in Java. The JDK JCE package offers the SHA1 algorithm through a generic message. ImmediateCrypt.png' alt='Program Encryption Decryption Java' title='Program Encryption Decryption Java' />Input. Stream and then call the read. Public. Key method that was provided for us by the Key. Based. File. Processor File. Input. Streamin new File. Input. Streampublic. Key. File. Path PGPPublic. Key key read. Public. Keyin At this point its important to note that the PGPPublic. Key. Ring class at least in the version I was using appears to have a bug where it only recognizes the first key in the keyring. If you use the get. User. Ids method of the object returned youll only see one key for java. Iterator iterator key. User. IDs iterator. Next System. Stringiterator. This could cause you problems if you have multiple keys in your keyring and if the first key is not an RSA or El Gamal key. Finally, create an armored ASCII text file and call the encrypt. File method again provided us by the Key. Based. File. Processor example File. Output. Stream out new File. Output. Streamoutputfile. Absolute. Path. Fileoutputfile. Absolute. Path, out, key The rest of the example is almost verbatim from the Key. Base. File. Processor example, Ill paste the code here, but I didnt do much to it out new Armored. Output. Streamout Byte. Array. Output. Stream b. Out new Byte. Array. Output. Stream PGPCompressed. Data. Generator com. Data new PGPCompressed. Data. GeneratorPGPCompressed. Data. Generator. ZIP PGPUtil. File. To. Literal. Datacom. Data. openb. Rise Of The Reds 1.04 on this page. Out, PGPLiteral. Data. BINARY, new Filefile. Poweriso 3.8 on this page. Name com. Data. PGPEncrypted. Data. Generator c. Pk new PGPEncrypted. Data. GeneratorPGPEncrypted. Data. Generator. CAST5, new Secure. Random, BC c. Pk. Methodenc. Key byte bytes b. Out. to. Byte. Array Output. Stream c. Out c. Pk. Out. writebytes c. Pk. close out. One last thing that I gleamed from their web based forum was that one of the exceptions thrown by the above code is a PGPException, which itself doesnt tell you much in my case it was simply saying exception encrypting session key. PGPException can be a wrapper for an underlying exception though, and you should use the get. Underlying. Exception method to determine what the real cause of the problem is which lead me to the Cant use DSA for encryption message that I mentioned above. You can download the source code and batch file for the example above here bouncycastlepgpexample. Updated 0. 40. 72. David Hook wrote to let me know that there is a bug in the examples, I updated both the sample code above and the zip file that contains the full source code. Look at the beta versions for the updated examples.