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Class semper.statement.Statement

java.lang.Object
   |
   +----semper.statement.Statement

public abstract class Statement

extends Object

implements Serializable, Cloneable

Version:

$Revision: 1.48 $ $Date: 1998/06/15 14:56:37 $

Author:

Jesper Drud Nielsen ([email protected]), Thomas Sepstrup Nielsen ([email protected]), Torben Pryds Pedersen ([email protected])

See Also:

CryptoMan

certificate

cryptoInf

keyInfo

securityVal

Additional information about the cryptographic functions, which is not key specific.

Statement()

Creates a new Statement Object with empty history.

Statement(String, String)

Creates a new Statement object. Deprecated.

clone()

Making clone public

copyFrom(Statement)

hm?

decipher(CryptoKeyInfo)

Decipher an encrypted statement.

delinearize(byte[])

"Helper" method to delinearize an array of bytes into the statement ToDo : elaborate explanation (consider the relation to serializables)

encipher(CryptoKeyInfo)

Encipher a statement using a conventional crypto system.

generateMAC(CryptoKeyInfo, Date, MACAlgorithm)

Generate a (keyed) MAC value on a statement object. Deprecated.

generateMAC(CryptoKeyInfo, MACAlgorithm)

Generate a (keyed) MAC value on a statement object.

generateSignature(CryptoKeyInfo, HashingAlgorithm, Certificate)

Sign a statement.

getAlg()

Returns the cryptographic algorithm used in the Statement.

getCertificate()

Get the certificate in the Statement.

getDate()

Get the date. Deprecated.

getHistory()

Get the full history of the operations performed on the Statement.

getLastOperation()

Gets the most recent performed operation on the Statement.

getPlainText()

Returns the message using which this Statement was initiated.

getPrevious()

If a given Statement is obtained by making an operation on a Statement (sign, MAC) then this method can be used to retrieve that previous Statement.

getRecipient()

Get the information �contained in the Statement about the recipient. Deprecated.

getSender()

Get the information �contained in the Statement about the sender. Deprecated.

isEncrypted()

Tests if statement have just been Encrypted.

isMACed()

Tests if statement have just been MACed.

isPKEncrypted()

Tests if statement have just been PKEncrypted.

isPlainText()

Tests if statement has had no operation performed on it.

isSigned()

Tests if statement have just een signed.

linearize()

"Helper" method to linearize the statement into an array of bytes

pkDecipher(CryptoKeyInfo)

Decipher a pkEnciphered statement object.

pkEncipher(CryptoKeyInfo, ConventionalAlgorithm, KeyPadding)

Encipher a statement object under a random, conventional key using encipher, and include this key enciphered under a public key.

printContents()

Temporary function printing the history and securityVal

resolvePublicKey(CryptoKeyInfo)

Resolve public key.

setCertificate(Certificate)

Set the certificate in the Statement.

setDate(Date)

Set the date. Deprecated.

setOperation(MessageOperation)

Sets the most recent performed operation.

setRecipient(String)

Inserts identification of the recipient in Statement. Deprecated.

setSender(String)

Inserts identification of the sender in Statement. Deprecated.

verifyMAC(CryptoKeyInfo)

Verify a (keyed) MAC value on a statement object.

verifyMAC(TimeRange, CryptoKeyInfo, Statement)

Verify a (keyed) MAC value on a statement object. Deprecated.

verifySignature(CryptoKeyInfo)

Verify the signature in a signed statement..

verifySignature(TimeRange, CryptoKeyInfo)

Verify the signature in a signed statement. Deprecated.

 protected CryptoKeyInfo keyInfo

 protected Certificate certificate

 protected Constant cryptoInf

 protected byte securityVal[]

Additional information about the cryptographic functions, which is not key specific. E.g., designates hash function, padding of messages, MAC algorithms, encryption of conventional keys.

 public Statement()

Creates a new Statement Object with empty history.

 public Statement(String newSenderId,
                  String newRecipientId)

Note: Statement() is deprecated. The IDs are no longer member of the class.

Creates a new Statement object.

Parameters:

newSenderId - The sender identification

newRecipientId - The recipient identification

 public abstract Object getPlainText() throws StatementManException

Returns the message using which this Statement was initiated. If the message has been encrypted at some point an exception is thrown. This method is overridden in subclasses to return an object of a class with whcih the Statement was created. If the Statement has been signed/MACed several times this method will retrieve the original message.

Returns:

the object contained in the plaintext

Throws: StatementManException

if plain text can not be retrieved

 public Statement getPrevious() throws StatementManException

If a given Statement is obtained by making an operation on a Statement (sign, MAC) then this method can be used to retrieve that previous Statement. if a Statement has not been operated on or the last operation was encryption, then it is not possible to go back.

Returns:

the previous Statement

Throws: StatementManException

if it is not possible to go back

 protected void setOperation(MessageOperation operation)

Sets the most recent performed operation.

Parameters:

operation - the performed operation on the statement

 public MessageOperation getLastOperation()

Gets the most recent performed operation on the Statement.

Returns:

the most recent performed operation on the Statement.

 public void encipher(CryptoKeyInfo newKeyInfo) throws StatementManException

Encipher a statement using a conventional crypto system. During this process the Statement is changed in that the date, sender identification and recipient identification are removed. The method should be called from the corresponding method in the subclass, which will construct the actual ciphertext. Information on the key is added.

Parameters:

newKeyInfo - identifies the key under which to encipher

Throws: StatementManException

if the key information could not be added

See Also:

decipher, CryptoConstants

 public abstract void decipher(CryptoKeyInfo convKeyInfo) throws StatementManException

Decipher an encrypted statement. If a decipher key is provided in convKeyInfo, it is used to decipher. Otherwise, a decipher key is derived from the statement objects keyInfo attribute. This method should be implemented in the subclasses.

Parameters:

The - key needed for decryption (if null the key information from the Statement is used)

Throws: StatementManException

if the statement could not be deciphered

See Also:

encipher

 public void generateSignature(CryptoKeyInfo newKeyInfo,
                               HashingAlgorithm hashAlg,
                               Certificate newCertificate) throws StatementManException

Sign a statement. Linearises the Statement and hashes it using the hashalgorithm given as input parameter. A signature on the hash value is generated using the key in newKeyInfo. Afterwards the statement contains the linearised statement (before hashing), identification of the key (a certificate on the public key if supplied as input) used to sign and the signature.

Parameters:

newKeyInfo - the secret signature key

hashAlg - designates the hashing algorithm to be used (if a DSA signature is used SHS-1 will be used, overwriting ths parameter)

newCertificate - is the certificate to be added to the statement.

Throws: StatementManException

if signature generation failed

See Also:

verifySignature

 public void verifySignature(TimeRange validRange,
                             CryptoKeyInfo trustedPublicKey) throws StatementManException

Note: verifySignature() is deprecated. There is no longer any time stamp information in the class

Verify the signature in a signed statement. After verification the contents of message is delinearized into the statement. Thus this method changes the Statement!!!!

Parameters:

validRange - the timewindow in which the signature will be accepted. Ignored.

trustedPublicKey - is used to verify the signature. If no key is supplied the public key in the certificate is used.

Throws: StatementManException

if something went wrong during the verification

See Also:

generateSignature

 public boolean verifySignature(CryptoKeyInfo trustedPublicKey) throws StatementManException

Verify the signature in a signed statement.. This method DOES NOT alter the Statement. To obtain the Statemen, which was originally signed, use getPrevious().

Parameters:

trustedPublicKey - is used to verify the signature. If no key is supplied the public key in the certificate is used.

Returns:

true if the signture is valid with respect to the given key.

Throws: StatementManException

if something went wrong during the verification

See Also:

generateSignature, getPrevious

 protected CryptoKeyInfo resolvePublicKey(CryptoKeyInfo trustedPublicKey)

Resolve public key. The resolved key is either that provided (if not null) or the key from the certificate.

Parameters:

trustedPublicKey - used to verify the signature. If null (no key is supplied) the public key in the certificate is used.

Returns:

resolved public key or null

 public void generateMAC(CryptoKeyInfo newKeyInfo,
                         Date newdate,
                         MACAlgorithm MACalg) throws StatementManException

Note: generateMAC() is deprecated. There is no longer timestamp information in the class

Generate a (keyed) MAC value on a statement object. This method should be overridden in the subclasses. Information about the key used for MACing is stored in the resulting Statement.

Parameters:

newKeyInfo - the key to use during the MAC operation

newdate - is a timestamp of the operation

MACalg - describes the MAC algorithm to be used

Throws: StatementManException

if the MAC value could not be generated

See Also:

verifyMAC

 public void generateMAC(CryptoKeyInfo newKeyInfo,
                         MACAlgorithm MACalg) throws StatementManException

Generate a (keyed) MAC value on a statement object. This method should be overridden in the subclasses. Information about the key used for MACing is stored in the resulting Statement.

Parameters:

newKeyInfo - the key to use during the MAC operation

MACalg - describes the MAC algorithm to be used

Throws: StatementManException

if the MAC value could not be generated

See Also:

verifyMAC

 public void verifyMAC(TimeRange validRange,
                       CryptoKeyInfo newKeyInfo,
                       Statement origStatement) throws StatementManException

Note: verifyMAC() is deprecated. There is no longer time stamp information in the class

Verify a (keyed) MAC value on a statement object. Retrieve the MAC key using the keyInfo attribute and verify the MAC using this key. The statement on which the MAC was generated is delinearized into the statement. THIS METHOD TRANSFORMS THE OBJECT

Parameters:

validRange - is the timewindow in which to accept the MAC

newKeyInfo - the key to verify MAC with

origStatement - the original statement is copied into this.

Throws: StatementManException

if the MAC could not be verified

See Also:

generateMAC

 public boolean verifyMAC(CryptoKeyInfo newKeyInfo) throws StatementManException

Verify a (keyed) MAC value on a statement object. Retrieve the MAC key using the keyInfo attribute and verify the MAC using this key. The statement is NOT CHANGED during verification. To get the Statement which was originally authenticated, use getPrevious().

Parameters:

newKeyInfo - the key to verify MAC with

Returns:

true if the MAC value is correct with respect to the key.

Throws: StatementManException

if the MAC could not be verified

See Also:

generateMAC, getPrevious

 public void pkEncipher(CryptoKeyInfo newKeyInfo,
                        ConventionalAlgorithm convAlg,
                        KeyPadding keyEncoding) throws StatementManException

Encipher a statement object under a random, conventional key using encipher, and include this key enciphered under a public key.

Parameters:

newKeyInfo - is the public key to be used for encryption

convAlg - the conventional algorithm to be used (0 indicates no conventional encryption)

PublicKeyEncr - describes the way the conventional key is encrypted

Throws: StatementManException

if the encryption fails

See Also:

encipher, pkDecipher

 public void pkDecipher(CryptoKeyInfo secretKey) throws StatementManException

Decipher a pkEnciphered statement object. The enciphered conventional key is deciphered using the supplied secret (asymmetric) key. The resulting conventional key is used to decipher the statement using decipher.

Parameters:

newKeyInfo - is the key to be used for decryption

Throws: StatementManException

if the statement could not be deciphered

See Also:

pkEncipher, decipher

 public boolean isPlainText()

Tests if statement has had no operation performed on it.

Returns:

true if so, otherwise false

 public boolean isSigned()

Tests if statement have just een signed.

Returns:

true if last operation was a Sign operation, otherwise false

 public boolean isEncrypted()

Tests if statement have just been Encrypted.

Returns:

true if last operation was a Encrypt operation, otherwise false

 public boolean isPKEncrypted()

Tests if statement have just been PKEncrypted.

Returns:

true if last operation was a PKEncrypt operation, otherwise false

 public void copyFrom(Statement src)

hm?

 public boolean isMACed()

Tests if statement have just been MACed.

Returns:

true if last operation was a MACoperation, otherwise false

 public void setDate(Date newDate)

Note: setDate() is deprecated. Has no longer any meaning. Nothing happens when calling this method.

Set the date. This function can be used to put a timestamp in a statement.

Parameters:

newDate - is the Date to be set in a Statement

 public Date getDate()

Note: getDate() is deprecated. No longer any meaning. There is no time stamp in the statement.

Get the date.

Returns:

the current time (instead of the time stamp)

 public Certificate getCertificate()

Get the certificate in the Statement.

Returns:

Certificate in statement (possibly null)

 public void setCertificate(Certificate cert)

Set the certificate in the Statement.

Parameters:

Certificate - in statement (possibly null)

 public KeyType getAlg()

Returns the cryptographic algorithm used in the Statement. In case more operations have been done the last one is returned.

Returns:

an integer describing the algorithm used to protect the statement (if the statement is not protected 0 is returned)

 public void setSender(String sender)

Note: setSender() is deprecated. There is no longer any information in the class pertaining to this issue.

Inserts identification of the sender in Statement. A null string clears all information about the sender.

Parameters:

sender - identifies the sender

See Also:

getSender

 public String getSender()

Note: getSender() is deprecated. There is no longer any information in the class pertaining to this issue.

Get the information �contained in the Statement about the sender. A null string means that the statement contains no information about the sender.

Returns:

the sender identification

See Also:

setSender

 public void setRecipient(String recipient)

Note: setRecipient() is deprecated. There is no longer any information in the class pertaining to this issue.

Inserts identification of the recipient in Statement. A null string clears all information about the recipient.

Parameters:

the - recipient identification

See Also:

getRecipient

 public String getRecipient()

Note: getRecipient() is deprecated. There is no longer any information in the class pertaining to this issue.

Get the information �contained in the Statement about the recipient. A null string means that the statement contains no information about the recipient.

Returns:

the recipient identification

See Also:

setRecipient

 public Stack getHistory()

Get the full history of the operations performed on the Statement.

Returns:

the history as a stack

 protected byte[] linearize() throws StatementManException

"Helper" method to linearize the statement into an array of bytes

Returns:

A string containing the linearized statement.

Throws: StatementManException

if the statement could not be linearised.

 protected Statement delinearize(byte _byteArray[]) throws StatementManException

"Helper" method to delinearize an array of bytes into the statement ToDo : elaborate explanation (consider the relation to serializables)

Parameters:

_byteArray - the array containing the linearized statement

Throws: StatementManException

if the object could not be delinearized

 public synchronized Object clone()

Making clone public

Returns:

a clone of myself

Overrides:

clone in class Object

 public void printContents()

Temporary function printing the history and securityVal

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