org.apache.poi.poifs.crypt.cryptoapi
Class CryptoAPIDecryptor

java.lang.Object
  extended by org.apache.poi.poifs.crypt.Decryptor
      extended by org.apache.poi.poifs.crypt.cryptoapi.CryptoAPIDecryptor

public class CryptoAPIDecryptor
extends Decryptor


Field Summary
 
Fields inherited from class org.apache.poi.poifs.crypt.Decryptor
builder, DEFAULT_PASSWORD, DEFAULT_POIFS_ENTRY
 
Constructor Summary
protected CryptoAPIDecryptor(CryptoAPIEncryptionInfoBuilder builder)
           
 
Method Summary
protected static javax.crypto.SecretKey generateSecretKey(java.lang.String password, EncryptionVerifier ver)
           
 java.io.InputStream getDataStream(DirectoryNode dir)
          Decrypt the Document-/SummaryInformation and other optionally streams.
 long getLength()
          Returns the length of the encrypted data that can be safely read with Decryptor.getDataStream(org.apache.poi.poifs.filesystem.DirectoryNode).
 javax.crypto.Cipher initCipherForBlock(javax.crypto.Cipher cipher, int block)
          Initializes a cipher object for a given block index for decryption
protected static javax.crypto.Cipher initCipherForBlock(javax.crypto.Cipher cipher, int block, EncryptionInfoBuilder builder, javax.crypto.SecretKey skey, int encryptMode)
           
 boolean verifyPassword(java.lang.String password)
           
 
Methods inherited from class org.apache.poi.poifs.crypt.Decryptor
getBlockSizeInBytes, getDataStream, getDataStream, getDataStream, getInstance, getIntegrityHmacKey, getIntegrityHmacValue, getKeySizeInBytes, getSecretKey, getVerifier, setIntegrityHmacKey, setIntegrityHmacValue, setSecretKey, setVerifier
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

CryptoAPIDecryptor

protected CryptoAPIDecryptor(CryptoAPIEncryptionInfoBuilder builder)
Method Detail

verifyPassword

public boolean verifyPassword(java.lang.String password)
Specified by:
verifyPassword in class Decryptor

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 decryption

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

initCipherForBlock

protected static javax.crypto.Cipher initCipherForBlock(javax.crypto.Cipher cipher,
                                                        int block,
                                                        EncryptionInfoBuilder builder,
                                                        javax.crypto.SecretKey skey,
                                                        int encryptMode)
                                                 throws java.security.GeneralSecurityException
Throws:
java.security.GeneralSecurityException

generateSecretKey

protected static javax.crypto.SecretKey generateSecretKey(java.lang.String password,
                                                          EncryptionVerifier ver)

getDataStream

public java.io.InputStream getDataStream(DirectoryNode dir)
                                  throws java.io.IOException,
                                         java.security.GeneralSecurityException
Decrypt the Document-/SummaryInformation and other optionally streams. Opposed to other crypto modes, cryptoapi is record based and can't be used to stream-decrypt a whole file

Specified by:
getDataStream in class Decryptor
Parameters:
dir - the node to read from
Returns:
decrypted stream
Throws:
java.io.IOException
java.security.GeneralSecurityException
See Also:
2.3.5.4 RC4 CryptoAPI Encrypted Summary Stream

getLength

public long getLength()
Description copied from class: Decryptor
Returns the length of the encrypted data that can be safely read with Decryptor.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 Decryptor.getDataStream(org.apache.poi.poifs.filesystem.DirectoryNode), an attempt to call getLength() prior to getDataStream() will result in IllegalStateException.

Specified by:
getLength in class Decryptor
Returns:
the length of the stream returned by getDataStream(DirectoryNode)


Copyright 2016 The Apache Software Foundation or its licensors, as applicable.