org.snmp4j.security
Class Priv3DES

java.lang.Object
  extended by org.snmp4j.security.Priv3DES
All Implemented Interfaces:
java.io.Serializable, PrivacyProtocol, SecurityProtocol

public class Priv3DES
extends java.lang.Object
implements PrivacyProtocol

Privacy protocol class for Triple DES (DESEDE). This class uses DES-EDE in CBC mode to encrypt the data. The protocol is defined by the Internet Draft 'Extension to the User-Based Security Model (USM) to Support Triple-DES EDE in "Outside" CBC Mode'.

Since:
1.9
Version:
1.9
Author:
Frank Fock, Jochen Katz
See Also:
Serialized Form

Field Summary
static OID ID
          Unique ID of this privacy protocol.
protected  org.snmp4j.security.Salt salt
           
 
Constructor Summary
Priv3DES()
           
 
Method Summary
 byte[] decrypt(byte[] cryptedData, int offset, int length, byte[] decryptionKey, long engineBoots, long engineTime, DecryptParams decryptParams)
          Decrypts a message using a given decryption key, engine boots count, and engine ID.
 byte[] encrypt(byte[] unencryptedData, int offset, int length, byte[] encryptionKey, long engineBoots, long engineTime, DecryptParams decryptParams)
          Encrypts a message using a given encryption key, engine boots count, and engine ID.
 byte[] extendShortKey(byte[] shortKey, OctetString password, byte[] engineID, AuthenticationProtocol authProtocol)
          Extend a localized key that is too short.
 int getDecryptParamsLength()
          Gets the length of the decryption parameters used by this security protocol.
 int getEncryptedLength(int scopedPDULength)
          Gets the length of a scoped PDU when encrypted with this security protocol.
 OID getID()
          Gets the OID uniquely identifying the privacy protocol.
 int getMaxKeyLength()
          Gets the maximum key size for this privacy protcol.
 int getMinKeyLength()
          Gets the minimum key size for this privacy protcol.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

ID

public static final OID ID
Unique ID of this privacy protocol.


salt

protected org.snmp4j.security.Salt salt
Constructor Detail

Priv3DES

public Priv3DES()
Method Detail

encrypt

public byte[] encrypt(byte[] unencryptedData,
                      int offset,
                      int length,
                      byte[] encryptionKey,
                      long engineBoots,
                      long engineTime,
                      DecryptParams decryptParams)
Description copied from interface: PrivacyProtocol
Encrypts a message using a given encryption key, engine boots count, and engine ID.

Specified by:
encrypt in interface PrivacyProtocol
Parameters:
unencryptedData - the unencrypted data. This byte array may contain leading and trailing bytes that will not be encrypted.
offset - the offset into the unencryptedData where to start encryption.
length - the length of the substring starting at offset to encrypt.
encryptionKey - the key to be used for encryption.
engineBoots - the engine boots counter to use.
engineTime - the engine time to use.
decryptParams - returns the decryption parameters needed to decrypt the data that has been encrypted by this method.
Returns:
the encrypted copy of unencryptedData.

decrypt

public byte[] decrypt(byte[] cryptedData,
                      int offset,
                      int length,
                      byte[] decryptionKey,
                      long engineBoots,
                      long engineTime,
                      DecryptParams decryptParams)
Description copied from interface: PrivacyProtocol
Decrypts a message using a given decryption key, engine boots count, and engine ID.

Specified by:
decrypt in interface PrivacyProtocol
Parameters:
cryptedData - the crypted data. This byte array may contain leading and trailing bytes that will not be decrypted.
offset - the offset into the cryptedData where to start encryption.
length - the length of the substring starting at offset to decrypt.
decryptionKey - the key to be used for decryption.
engineBoots - the engine boots counter to use.
engineTime - the engine time to use.
decryptParams - contains the decryption parameters.
Returns:
the decrypted data, or null if decryption failed.

getID

public OID getID()
Gets the OID uniquely identifying the privacy protocol.

Specified by:
getID in interface PrivacyProtocol
Specified by:
getID in interface SecurityProtocol
Returns:
an OID instance.

getEncryptedLength

public int getEncryptedLength(int scopedPDULength)
Description copied from interface: PrivacyProtocol
Gets the length of a scoped PDU when encrypted with this security protocol.

Specified by:
getEncryptedLength in interface PrivacyProtocol
Parameters:
scopedPDULength - the length of the (unencrypted) scoped PDU.
Returns:
the length of the encrypted scoped PDU.

getMinKeyLength

public int getMinKeyLength()
Description copied from interface: PrivacyProtocol
Gets the minimum key size for this privacy protcol.

Specified by:
getMinKeyLength in interface PrivacyProtocol
Returns:
the minimum key size for this privacy protcol.

getDecryptParamsLength

public int getDecryptParamsLength()
Description copied from interface: PrivacyProtocol
Gets the length of the decryption parameters used by this security protocol.

Specified by:
getDecryptParamsLength in interface PrivacyProtocol
Returns:
a positive integer denoting the length of decryption parameters returned by this security protocol.

getMaxKeyLength

public int getMaxKeyLength()
Description copied from interface: PrivacyProtocol
Gets the maximum key size for this privacy protcol.

Specified by:
getMaxKeyLength in interface PrivacyProtocol
Returns:
the minimum key size for this privacy protcol.

extendShortKey

public byte[] extendShortKey(byte[] shortKey,
                             OctetString password,
                             byte[] engineID,
                             AuthenticationProtocol authProtocol)
Description copied from interface: PrivacyProtocol
Extend a localized key that is too short. Some privacy protocols require a key that is longer than the key generated by the pasword to key algorithm of the authentication protocol. This function extends a short key to the required length.

Specified by:
extendShortKey in interface PrivacyProtocol
Parameters:
shortKey - the short key that was generated using AuthenticationProtocol.passwordToKey(org.snmp4j.smi.OctetString, byte[]) function.
password - the password to use for key extension.
engineID - the SNMP engine ID of the authoritative engine.
authProtocol - the authentication protocol that should be used.
Returns:
the extended key or shortKey if no extension is needed.

Copyright 2005-2010 Frank Fock (SNMP4J.org)

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