com.dpslink.base.util

Class StringEncrypter

java.lang.Object

com.dpslink.base.util.StringEncrypter

All Implemented Interfaces:

java.io.Serializable

public class StringEncrypter
extends java.lang.Object
implements java.io.Serializable

A utility class that provides string encryption and decryption functions that are based on DES algorithms.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
private static java.util.Base64.Decoder	cvDecoder A base 64 decoder.
private static javax.crypto.Cipher	cvDecryptCipher The cipher for decryption.
private static java.util.Base64.Encoder	cvEncoder A base 64 encoder.
private static javax.crypto.Cipher	cvEncryptCipher The cipher for encryption.
private static javax.crypto.spec.PBEParameterSpec	cvPbeParamSpec The PBE parameter specification.
private static long	serialVersionUID The class' serialization version id.

Constructor Summary

Constructors

Constructor and Description
StringEncrypter()

Method Summary

Modifier and Type	Method and Description
static java.lang.String	byteToHexString(byte[] b) Converts a byte array to a string of hex chars.
static java.lang.String	decrypt(java.lang.String s) Decrypts the given string.
static java.lang.String	encrypt(java.lang.String s) Encrypts the given string.
private static int	fromDigit(char ch) Returns the hex value of a character.
private static javax.crypto.SecretKey	getSecretKey(java.lang.String trans, java.lang.String pwd, byte[] salt, int count) Generates the key used for encryption/decryption.
static byte[]	hexStringToByte(java.lang.String hex) Converts a string of hex to a byte array.
static boolean	isCryptoInstalled() Answers if the cryptography supporting classes are installed.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

serialVersionUID

private static final long serialVersionUID

The class' serialization version id.

See Also:

Constant Field Values

cvPbeParamSpec

private static javax.crypto.spec.PBEParameterSpec cvPbeParamSpec

The PBE parameter specification.

cvEncryptCipher

private static javax.crypto.Cipher cvEncryptCipher

The cipher for encryption.

cvDecryptCipher

private static javax.crypto.Cipher cvDecryptCipher

The cipher for decryption.

cvEncoder

private static java.util.Base64.Encoder cvEncoder

A base 64 encoder.

cvDecoder

private static java.util.Base64.Decoder cvDecoder

A base 64 decoder.

Constructor Detail

StringEncrypter

public StringEncrypter()

Method Detail

decrypt

public static java.lang.String decrypt(java.lang.String s)

Decrypts the given string. The string must have been encrypted by the encrypt method of this class. Returns the same string if the cryptography classes are not installed.

Parameters:

s - (String) The string to be decrypted.

Returns:

String - The decrypted string.

encrypt

public static java.lang.String encrypt(java.lang.String s)

Encrypts the given string. The string must be decrypted by the decrypt method of this class. Returns the same string if the cryptography classes are not installed.

Parameters:

s - (String) The string to be encrypted.

Returns:

String - The encrypted string.

getSecretKey

private static javax.crypto.SecretKey getSecretKey(java.lang.String trans,
                                                   java.lang.String pwd,
                                                   byte[] salt,
                                                   int count)

Generates the key used for encryption/decryption.

Parameters:

trans - (String) The encryption transformation parameter.

pwd - (String) The password.

salt - (byte[]) The salt.

count - (int) The count.

Returns:

SecretKey - The secret key.

byteToHexString

public static java.lang.String byteToHexString(byte[] b)

Converts a byte array to a string of hex chars. {x'ff', x'10'} => "FF10"

Parameters:

b - (byte[]) The byte values to convert.

Returns:

String - A string of hex characters.

hexStringToByte

public static byte[] hexStringToByte(java.lang.String hex)

Converts a string of hex to a byte array. FF10 => {x'ff', x'10'}

Parameters:

hex - (String) A string of hex characters eg.: 0123456789abcdef

Returns:

byte[] - The byte values for the string hex characters.

fromDigit

private static int fromDigit(char ch)

Returns the hex value of a character. 'F' => 15, '0' => 0

Parameters:

ch - (char) A character.

Returns:

int - The hex value of the character.

isCryptoInstalled

public static boolean isCryptoInstalled()

Answers if the cryptography supporting classes are installed.

Returns:

boolean - true if the cryptography classes are installed, otherwise false.