org.snmp4j.security

Class PrivDES

java.lang.Object

org.snmp4j.security.PrivDES

All Implemented Interfaces:

Serializable, PrivacyProtocol, SecurityProtocol

public class PrivDES
extends Object
implements PrivacyProtocol

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:

1.9

Author:

Jochen Katz

See Also:

Serialized Form

Field Summary

Fields

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

Constructor Summary

Constructors

Constructor and Description
PrivDES()

Method Summary

Methods

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 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

cipherPool

protected CipherPool cipherPool

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.

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)

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

Specified by:

decrypt in interface PrivacyProtocol

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.

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 password-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.