Package org.bouncycastle.openpgp

Class PGPEncryptedDataGenerator

java.lang.Object

org.bouncycastle.openpgp.PGPEncryptedDataGenerator

All Implemented Interfaces:

SymmetricKeyAlgorithmTags

public class PGPEncryptedDataGenerator
extends java.lang.Object
implements SymmetricKeyAlgorithmTags

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

Fields

Modifier and Type	Field	Description
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

Constructors

Constructor	Description
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

Modifier and Type	Method	Description
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.

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.

See Also:

Constant Field Values

S2K_SHA224

public static final int S2K_SHA224

Specifier for SHA-224 S2K PBE generator.

See Also:

Constant Field Values

S2K_SHA256

public static final int S2K_SHA256

Specifier for SHA-256 S2K PBE generator.

See Also:

Constant Field Values

S2K_SHA384

public static final int S2K_SHA384

Specifier for SHA-384 S2K PBE generator.

See Also:

Constant Field Values

S2K_SHA512

public static final int S2K_SHA512

Specifier for SHA-512 S2K PBE generator.

See Also:

Constant Field Values

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 required.

Method Detail

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.

Throws:

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