Hello.

I've got a system where a client requests some data. To protect the data,
they're encrypted with a symmetric session key (of length let's say 186
bit). The session key itself has to be encrypted with several different
public RSA keys, because the client has to prove that (s)he possesses all
corresponding private keys.
The problem is that javax.crypto.Cipher (together with BouncyCastle RSA)
produces a byte [] with length 128 (RSA key length is 1024 bit). So
_sometimes_ the subsequent intents to encrypt this byte [] fail with:

org.bouncycastle.crypto.DataLengthException: input too large for RSA cipher.
       at
org.bouncycastle.crypto.engines.RSAEngine.processBlock(RSAEngine.java:96)

But this is not always the case -- how can it be so undeterministic?

Even with the "NoPadding" option the problem remains:
Cipher.getInstance("RSA/ECB/NoPadding", new  
org.bouncycastle.jce.provider.BouncyCastleProvider());

With what does the RSA algorithm fill the byte []?
Is there a possibility not to produce a 128 byte output during the first
encryption steps and create the 128 byte output only in the last step?

Any help will be appreciated
 Lena