org.snmp4j.security

Class PrivDES

java.lang.Object

org.snmp4j.security.PrivacyGeneric

org.snmp4j.security.PrivDES

All Implemented Interfaces:

Serializable, PrivacyProtocol, SecurityProtocol

public class PrivDES
extends PrivacyGeneric

Privacy protocol class for DES. This class uses DES in CBC mode to encrypt the data. The protocol is defined in the IETF standard "User-based Security Model (USM) for SNMPv3".

Version:

2.5.0

Author:

Jochen Katz

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static OID	ID Unique ID of this privacy protocol.
protected org.snmp4j.security.Salt	salt

Fields inherited from class org.snmp4j.security.PrivacyGeneric

cipherPool, initVectorLength, keyBytes, protocolClass, protocolId

Constructor Summary

Constructors

Constructor and Description
PrivDES()

Method Summary

Modifier and Type	Method and Description
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 protocol.
int	getMinKeyLength() Gets the minimum key size for this privacy protocol.
boolean	isSupported() Checks whether this security protocol is actually supported by this Java runtime environment.

Methods inherited from class org.snmp4j.security.PrivacyGeneric

doDecrypt, doFinal, doFinalWithPadding, doInit

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

PrivDES

public PrivDES()

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.

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)

Decrypts a message using a given decryption key, engine boots count, and engine ID.

Parameters:

cryptedData - the data to decrypt.

offset - the offset into cryptedData to start decryption.

length - the length of the data to decrypt.

decryptionKey - the decryption key.

engineBoots - the engine boots counter.

engineTime - the engine time value.

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.

Returns:

an OID instance.

isSupported

public boolean isSupported()

Description copied from interface: SecurityProtocol

Checks whether this security protocol is actually supported by this Java runtime environment.

Specified by:

isSupported in interface SecurityProtocol

Overrides:

isSupported in class PrivacyGeneric

Returns:

true if this security protocol is supported, false otherwise.

getEncryptedLength

public int getEncryptedLength(int scopedPDULength)

Description copied from interface: PrivacyProtocol

Gets the length of a scoped PDU when encrypted with this security protocol.

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 protocol.

Returns:

the minimum key size for this privacy protocol.

getDecryptParamsLength

public int getDecryptParamsLength()

Description copied from interface: PrivacyProtocol

Gets the length of the decryption parameters used by this security protocol.

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 protocol.

Returns:

the minimum key size for this privacy protocol.

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 password-to-key algorithm of the authentication protocol. This function extends a short key to the required length.

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.