Package org.apache.poi.poifs.crypt
Class Decryptor
java.lang.Object
org.apache.poi.poifs.crypt.Decryptor
- All Implemented Interfaces:
Cloneable
- Direct Known Subclasses:
AgileDecryptor
,BinaryRC4Decryptor
,CryptoAPIDecryptor
,StandardDecryptor
,XORDecryptor
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic final String
static final String
protected EncryptionInfo
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionclone()
protected int
getDataStream
(InputStream stream, int size, int initialPos) Wraps a stream for decryptionabstract InputStream
Return a stream with decrypted data.static Decryptor
getInstance
(EncryptionInfo info) byte[]
byte[]
protected int
abstract long
Returns the length of the encrypted data that can be safely read withgetDataStream(org.apache.poi.poifs.filesystem.DirectoryNode)
.byte[]
initCipherForBlock
(Cipher cipher, int block) Initializes a cipher object for a given block index for encryptionvoid
setChunkSize
(int chunkSize) Sets the chunk size of the data stream.void
setEncryptionInfo
(EncryptionInfo encryptionInfo) protected void
setIntegrityHmacKey
(byte[] integrityHmacKey) protected void
setIntegrityHmacValue
(byte[] integrityHmacValue) protected void
setSecretKey
(SecretKey secretKey) protected void
setVerifier
(byte[] verifier) abstract boolean
verifyPassword
(String password)
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Field Details
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DEFAULT_PASSWORD
- See Also:
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DEFAULT_POIFS_ENTRY
- See Also:
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encryptionInfo
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Constructor Details
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Decryptor
protected Decryptor()
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Method Details
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getDataStream
public abstract InputStream getDataStream(DirectoryNode dir) throws IOException, 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:
IOException
GeneralSecurityException
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getDataStream
public InputStream getDataStream(InputStream stream, int size, int initialPos) throws IOException, GeneralSecurityException Wraps a stream for decryptionAs 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 wrappedinitialPos
- initial/current byte position within the stream- Returns:
- decrypted stream
- Throws:
IOException
GeneralSecurityException
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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
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initCipherForBlock
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 indexblock
- the block index, e.g. the persist/slide id (hslf)- Returns:
- a new cipher object, if cipher was null, otherwise the reinitialized cipher
- Throws:
GeneralSecurityException
- if the cipher can't be initialized
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verifyPassword
- Throws:
GeneralSecurityException
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getLength
public abstract long getLength()Returns the length of the encrypted data that can be safely read withgetDataStream(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 discardedThe 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:
IllegalStateException
- ifgetDataStream(org.apache.poi.poifs.filesystem.DirectoryNode)
was not called
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getInstance
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getDataStream
- Throws:
IOException
GeneralSecurityException
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getVerifier
public byte[] getVerifier() -
getSecretKey
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getIntegrityHmacKey
public byte[] getIntegrityHmacKey() -
getIntegrityHmacValue
public byte[] getIntegrityHmacValue() -
setSecretKey
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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
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setEncryptionInfo
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clone
- Overrides:
clone
in classObject
- Throws:
CloneNotSupportedException
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