org.bouncycastle.openpgp
Class PGPEncryptedDataGenerator

java.lang.Object
  |
  +--org.bouncycastle.openpgp.PGPEncryptedDataGenerator

All Implemented Interfaces:

org.bouncycastle.openpgp.StreamGenerator, SymmetricKeyAlgorithmTags

public class PGPEncryptedDataGenerator

extends java.lang.Object

implements SymmetricKeyAlgorithmTags, org.bouncycastle.openpgp.StreamGenerator

Generator for encrypted objects.

A PGPEncryptedDataGenerator is used by configuring one or more encryption methods, and then invoking one of the open functions to create an OutputStream that raw data can be supplied to for encryption:

If the length of the data to be written is known in advance, use open(OutputStream, long) to create a packet containing a single encrypted object. If the length of the data is unknown, use open(OutputStream, byte[]) to create an packet consisting of a series of encrypted objects (partials).

Raw data is not typically written directly to the OutputStream obtained from a PGPEncryptedDataGenerator. The OutputStream is usually wrapped by a PGPLiteralDataGenerator, and often with a PGPCompressedDataGenerator between.

Once plaintext data for encryption has been written to the constructed OutputStream, writing of the encrypted object stream is completed by closing the OutputStream obtained from the open() method, or equivalently invoking close() on this generator.

Field Summary

static int	S2K_SHA1 Specifier for SHA-1 S2K PBE generator.
static int	S2K_SHA224 Specifier for SHA-224 S2K PBE generator.
static int	S2K_SHA256 Specifier for SHA-256 S2K PBE generator.
static int	S2K_SHA384 Specifier for SHA-384 S2K PBE generator.
static int	S2K_SHA512 Specifier for SHA-512 S2K PBE generator.

Fields inherited from interface org.bouncycastle.bcpg.SymmetricKeyAlgorithmTags

AES_128, AES_192, AES_256, BLOWFISH, CAMELLIA_128, CAMELLIA_192, CAMELLIA_256, CAST5, DES, IDEA, NULL, SAFER, TRIPLE_DES, TWOFISH

Constructor Summary

PGPEncryptedDataGenerator(PGPDataEncryptorBuilder encryptorBuilder)
Base constructor.

PGPEncryptedDataGenerator(PGPDataEncryptorBuilder encryptorBuilder, boolean oldFormat)
Base constructor with the option to turn on formatting for PGP 2.6.x compatibility.

Method Summary

void	addMethod(PGPKeyEncryptionMethodGenerator method) Add a key encryption method to be used to encrypt the session data associated with this encrypted data.
void	close() Close off the encrypted object - this is equivalent to calling close on the stream returned by the open() methods.
java.io.OutputStream	open(java.io.OutputStream out, byte[] buffer) Create an OutputStream which will encrypt the data as it is written to it.
java.io.OutputStream	open(java.io.OutputStream out, long length) Create an OutputStream based on the configured methods to write a single encrypted object of known length.
void	setForceSessionKey(boolean forceSessionKey) Some versions of PGP always expect a session key, this will force use of a session key even if a single PBE encryptor is provided.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

S2K_SHA1

public static final int S2K_SHA1

Specifier for SHA-1 S2K PBE generator.

S2K_SHA224

public static final int S2K_SHA224

Specifier for SHA-224 S2K PBE generator.

S2K_SHA256

public static final int S2K_SHA256

Specifier for SHA-256 S2K PBE generator.

S2K_SHA384

public static final int S2K_SHA384

Specifier for SHA-384 S2K PBE generator.

S2K_SHA512

public static final int S2K_SHA512

Specifier for SHA-512 S2K PBE generator.

Constructor Detail

PGPEncryptedDataGenerator

public PGPEncryptedDataGenerator(PGPDataEncryptorBuilder encryptorBuilder)

Base constructor.

Parameters:

encryptorBuilder - builder to create actual data encryptor.

PGPEncryptedDataGenerator

public PGPEncryptedDataGenerator(PGPDataEncryptorBuilder encryptorBuilder,
                                 boolean oldFormat)

Base constructor with the option to turn on formatting for PGP 2.6.x compatibility.

Parameters:

encryptorBuilder - builder to create actual data encryptor.

oldFormat - PGP 2.6.x compatibility requested.

Method Detail

setForceSessionKey

public void setForceSessionKey(boolean forceSessionKey)

Some versions of PGP always expect a session key, this will force use of a session key even if a single PBE encryptor is provided.

Parameters:

forceSessionKey - true if a session key should always be used, default is false.

addMethod

public void addMethod(PGPKeyEncryptionMethodGenerator method)

Add a key encryption method to be used to encrypt the session data associated with this encrypted data.

Parameters:

method - key encryption method to use.

open

public java.io.OutputStream open(java.io.OutputStream out,
                                 long length)
                          throws java.io.IOException,
                                 PGPException

Create an OutputStream based on the configured methods to write a single encrypted object of known length.

The stream created can be closed off by either calling close() on the stream or close() on the generator. Closing the returned stream does not close off the OutputStream parameter out.

Parameters:

out - the stream to write encrypted packets to.

length - the length of the data to be encrypted.

Returns:

the output stream to write data to for encryption.

Throws:

java.io.IOException - if an error occurs writing stream header information to the provider output stream.

PGPException - if an error occurs initialising PGP encryption for the configured encryption methods.

java.lang.IllegalStateException - if this generator already has an open OutputStream, or no encryption methods are configured.

open

public java.io.OutputStream open(java.io.OutputStream out,
                                 byte[] buffer)
                          throws java.io.IOException,
                                 PGPException

Create an OutputStream which will encrypt the data as it is written to it. The stream of encrypted data will be written out in chunks (partial packets) according to the size of the passed in buffer.

The stream created can be closed off by either calling close() on the stream or close() on the generator. Closing the returned stream does not close off the OutputStream parameter out.

Note: if the buffer is not a power of 2 in length only the largest power of 2 bytes worth of the buffer will be used.

Parameters:

out - the stream to write encrypted packets to.

buffer - a buffer to use to buffer and write partial packets. The returned stream takes ownership of the buffer and will use it to buffer plaintext data for encryption.

Returns:

the output stream to write data to for encryption.

Throws:

java.io.IOException - if an error occurs writing stream header information to the provider output stream.

PGPException - if an error occurs initialising PGP encryption for the configured encryption methods.

java.lang.IllegalStateException - if this generator already has an open OutputStream, or no encryption methods are configured.

close

public void close()
           throws java.io.IOException

Close off the encrypted object - this is equivalent to calling close on the stream returned by the open() methods.

Note: This does not close the underlying output stream, only the stream on top of it created by the open() method.

Specified by:

close in interface org.bouncycastle.openpgp.StreamGenerator

Throws:

java.io.IOException - if an error occurs writing trailing information (such as integrity check information) to the underlying stream.