org.apache.poi.poifs.crypt
Class Decryptor

java.lang.Object
  org.apache.poi.poifs.crypt.Decryptor

All Implemented Interfaces:

java.lang.Cloneable

Direct Known Subclasses:

BinaryRC4Decryptor, CryptoAPIDecryptor, StandardDecryptor, XORDecryptor

public abstract class Decryptor
extends java.lang.Object
implements java.lang.Cloneable

DEFAULT_PASSWORD

public static final java.lang.String DEFAULT_PASSWORD

See Also:

Constant Field Values

DEFAULT_POIFS_ENTRY

public static final java.lang.String DEFAULT_POIFS_ENTRY

See Also:

Constant Field Values

encryptionInfo

protected EncryptionInfo encryptionInfo

Decryptor

protected Decryptor()

getDataStream

public abstract java.io.InputStream getDataStream(DirectoryNode dir)
                                           throws java.io.IOException,
                                                  java.security.GeneralSecurityException

Return a stream with decrypted data.

Use getLength() to get the size of that data that can be safely read from the stream. Just reading to the end of the input stream is not sufficient because there are normally padding bytes that must be discarded

Parameters:

dir - the node to read from

Returns:

decrypted stream

Throws:

java.io.IOException

java.security.GeneralSecurityException

getDataStream

public java.io.InputStream getDataStream(java.io.InputStream stream,
                                         int size,
                                         int initialPos)
                                  throws java.io.IOException,
                                         java.security.GeneralSecurityException

Wraps a stream for decryption

As we are handling streams and don't know the total length beforehand, it's the callers duty to care for the length of the entries.

Parameters:

stream - the stream to be wrapped

initialPos - initial/current byte position within the stream

Returns:

decrypted stream

Throws:

java.io.IOException

java.security.GeneralSecurityException

setChunkSize

public void setChunkSize(int chunkSize)

Sets the chunk size of the data stream. Needs to be set before the data stream is requested. When not set, the implementation uses method specific default values

Parameters:

chunkSize - the chunk size, i.e. the block size with the same encryption key

initCipherForBlock

public javax.crypto.Cipher initCipherForBlock(javax.crypto.Cipher cipher,
                                              int block)
                                       throws java.security.GeneralSecurityException

Initializes a cipher object for a given block index for encryption

Parameters:

cipher - may be null, otherwise the given instance is reset to the new block index

block - the block index, e.g. the persist/slide id (hslf)

Returns:

a new cipher object, if cipher was null, otherwise the reinitialized cipher

Throws:

java.security.GeneralSecurityException

verifyPassword

public abstract boolean verifyPassword(java.lang.String password)
                                throws java.security.GeneralSecurityException

Throws:

java.security.GeneralSecurityException

getLength

public abstract long getLength()

Returns the length of the encrypted data that can be safely read with getDataStream(org.apache.poi.poifs.filesystem.DirectoryNode). Just reading to the end of the input stream is not sufficient because there are normally padding bytes that must be discarded

The length variable is initialized in getDataStream(org.apache.poi.poifs.filesystem.DirectoryNode), an attempt to call getLength() prior to getDataStream() will result in IllegalStateException.

Returns:

length of the encrypted data

Throws:

java.lang.IllegalStateException - if getDataStream(org.apache.poi.poifs.filesystem.DirectoryNode) was not called

getInstance

public static Decryptor getInstance(EncryptionInfo info)

getDataStream

public java.io.InputStream getDataStream(NPOIFSFileSystem fs)
                                  throws java.io.IOException,
                                         java.security.GeneralSecurityException

Throws:

java.io.IOException

java.security.GeneralSecurityException

getDataStream

public java.io.InputStream getDataStream(OPOIFSFileSystem fs)
                                  throws java.io.IOException,
                                         java.security.GeneralSecurityException

Throws:

java.io.IOException

java.security.GeneralSecurityException

getDataStream

public java.io.InputStream getDataStream(POIFSFileSystem fs)
                                  throws java.io.IOException,
                                         java.security.GeneralSecurityException

Throws:

java.io.IOException

java.security.GeneralSecurityException

getVerifier

public byte[] getVerifier()

getSecretKey

public javax.crypto.SecretKey getSecretKey()

getIntegrityHmacKey

public byte[] getIntegrityHmacKey()

getIntegrityHmacValue

public byte[] getIntegrityHmacValue()

setSecretKey

protected void setSecretKey(javax.crypto.SecretKey secretKey)

setVerifier

protected void setVerifier(byte[] verifier)

setIntegrityHmacKey

protected void setIntegrityHmacKey(byte[] integrityHmacKey)

setIntegrityHmacValue

protected void setIntegrityHmacValue(byte[] integrityHmacValue)

getBlockSizeInBytes

protected int getBlockSizeInBytes()

getKeySizeInBytes

protected int getKeySizeInBytes()

getEncryptionInfo

public EncryptionInfo getEncryptionInfo()

setEncryptionInfo

public void setEncryptionInfo(EncryptionInfo encryptionInfo)

clone

public Decryptor clone()
                throws java.lang.CloneNotSupportedException

Overrides:

clone in class java.lang.Object

Throws:

java.lang.CloneNotSupportedException