Comments on: Java RSA Encryption: An example

By: Mostrapotski

Mostrapotski — Mon, 30 Nov 2009 10:41:21 +0000

CSStudent: by sending a pigeon ! Or by using symmetric key, to exchange the asymmetric key… It roughly depends of the network structure you re dealing with.

Thx for the small tuto, very useful !

By: CSStudent

CSStudent — Tue, 06 Oct 2009 02:57:49 +0000

thats nice, except where do we magically get KeyPair to appear on the other computer?

By: Jihad

Jihad — Mon, 05 Oct 2009 18:10:25 +0000

i think there is still something missing in your code
i’ve tried to apply it but no matter what i do it get this
“java.security.InvalidKeyException: No installed provider supports this key: (null)”
i’ve tried to use the The Bouncy Castle Crypto APIs to get a provider
but still it did not work !
any ideas ?

By: rajeshkannan

rajeshkannan — Sat, 04 Apr 2009 07:14:52 +0000

Hai Andreas,
how to encrypt huge number of text using RSA with keypair generator?
can i get source code for this?

By: Frederic

Frederic — Thu, 08 Jan 2009 17:29:46 +0000

Thk for the example. I did not know about the US Cryptographic Export Laws.

2 notes :

1- There’s no mistake as Andreas explained, only some code portion missing (that was not needed).

2- String message = (String) myEncyptedMessage.getObject(dec); (without r) – or refactor the object.

By: Renato Back

Renato Back — Thu, 04 Dec 2008 04:41:21 +0000

I believe there’s a mistake and the following line

String message = (String)test.getObject(myEncyptedMessage);

Should actually be

String message = (String) myEncryptedMessage.getObject(dec);

Thanks for the tutorial, it really helps out.

Cheers!

By: Mic

Mic — Thu, 01 May 2008 10:19:39 +0000

I used this approach for encrypting files:
http://www-users.york.ac.uk/~mal503/lore/pkencryption.htm

It uses RSA to encrypt an AES shared key which is then used to encrypt the files. Not sure if it’s the best way of doing things, but it works

By: cp

cp — Wed, 30 Apr 2008 19:38:28 +0000

File, mpravo sigxaritira oti kalutero gia to mellon…

By: Andreas Louca

Andreas Louca — Tue, 08 Apr 2008 21:42:04 +0000

Well, SealedObject is not designed to be used in encrypting files. It can be used to encrypt a String with the contents of a file, but bear in mind that the RSA Encryption has the size limitation you mentioned. You can always use a symmetric Cipher to encrypt objects longer than that. If you want to encrypt a file however, Java provides CipherOutputStream for writing and CipherInputStream for reading encrypted data from Streams that can be either File or network streams. CipherOutputStream class takes as parameters an OutputStream (with the destination file) and Cipher (like the above) and encrypts the output before writing to the file. CipherInputStream can be used to read that file, providing that the same Cipher algorithm and key is used.

By: soul_krasty

soul_krasty — Tue, 08 Apr 2008 08:53:12 +0000

how about is i want to encrypt a file..i have read some article saying that RSA can’t encrypt file that are more than 117 bytes. can you explain more on sealobject being used with encrypting small file.