Encryption decryption using PKCS#7 - cryptography

Question

I want to encrypt decrypt data using PKCS #7.
While exploring i found a book Beginning Cryptography With Java
In ch 9 of the book is having a example code is below
import java.security.KeyStore;
import java.security.PrivateKey;
import java.security.cert.*;
import java.util.Arrays;
import org.bouncycastle.cms.CMSProcessable;
import org.bouncycastle.cms.CMSProcessableByteArray;
import org.bouncycastle.cms.CMSSignedData;
import org.bouncycastle.cms.CMSSignedDataGenerator;
/**
* Example of generating a detached signature.
*/
public class SignedDataExample
extends SignedDataProcessor
{
public static void main(String[] args) throws Exception
{
KeyStore credentials = Utils.createCredentials();
PrivateKey key = (PrivateKey)credentials.getKey(
Utils.END_ENTITY_ALIAS, Utils.KEY_PASSWD);
Certificate[] chain = credentials.getCertificateChain(
Utils.END_ENTITY_ALIAS);
CertStore certsAndCRLs = CertStore.getInstance(
"Collection", new CollectionCertStoreParameters(
Arrays.asList(chain)), "BC");
X509Certificate cert = (X509Certificate)chain[0];
// set up the generator
CMSSignedDataGenerator gen = new CMSSignedDataGenerator();
gen.addSigner(key, cert, CMSSignedDataGenerator.DIGEST_SHA224);
gen.addCertificatesAndCRLs(certsAndCRLs);
// create the signed-data object
CMSProcessable data = new CMSProcessableByteArray(
"Hello World!".getBytes());
CMSSignedData signed = gen.generate(data, "BC");
// re-create
signed = new CMSSignedData(data, signed.getEncoded());
// verification step
X509Certificate rootCert = (X509Certificate)credentials.getCertificate(
Utils.ROOT_ALIAS);
if (isValid(signed, rootCert))
{
System.out.println("verification succeeded");
}
else
{
System.out.println("verification failed");
}
}
}
I have couple of question
Where is encrypted data and how do i write it to file
How do i recover back original data from encrypted data
Do i need to send key store to the person who is decrypting the encrypted data.
In what format should i send encrypted data
Thanks A Lot