org.elkoserver.foundation.json

Class Cryptor

java.lang.Object

org.elkoserver.foundation.json.Cryptor

public class Cryptor
extends Object

Simple AES-based string encryptor/decryptor, for passing sealed bundles of data through an untrusted party.

Constructor Summary

Constructors

Constructor and Description
Cryptor(String keyStr) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
String	decrypt(String str) Decrypt a (base-64 encoded) encrypted string
JSONObject	decryptJSONObject(String str) Decrypt a (base-64 encoded) encrypted JSON object literal.
Object	decryptObject(Class baseType, String str) Decrypt and decode a (base-64 encoded) encrypted object serialized as a JSON object literal.
String	encrypt(String str) Produce a (base-64 encoded) encrypted version of a string.
static String	generateKey() Generate a new, random key.

Methods inherited from class java.lang.Object

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

Constructor Detail

Cryptor

public Cryptor(String keyStr)
        throws IOException

Constructor.

Parameters:

keyStr - Base64-encoded symmetric key.

Throws:

IOException - if the key string is malformed.

Method Detail

decrypt

public String decrypt(String str)
               throws IOException

Decrypt a (base-64 encoded) encrypted string

Parameters:

str - Encrypted string to be decrypted, as generated by the encrypt method of this class.

Returns:

the decrypted plaintext encoded in 'str'

Throws:

IOException - if the input string is malformed.

decryptJSONObject

public JSONObject decryptJSONObject(String str)
                             throws IOException,
                                    SyntaxError

Decrypt a (base-64 encoded) encrypted JSON object literal.

Parameters:

str - Encrypted string to be decrypted.

Returns:

The decrypted and parsed JSON object encoded in 'str'

Throws:

IOException - if the input string is malformed

SyntaxError - if the decrypted JSON literal is invalid

decryptObject

public Object decryptObject(Class baseType,
                   String str)
                     throws IOException

Decrypt and decode a (base-64 encoded) encrypted object serialized as a JSON object literal.

Parameters:

baseType - The desired class of the resulting Java object. The result will not necessarily be of this class, but will be assignable to a variable of this class.

str - Encrypted string to be decrypted.

Returns:

a new Java object assignable to the class in 'baseType' as described by the JSON literal obtained by decrypting 'str', or null if the JSON literal was syntactically malformed or if the object could not be decoded for some reason.

Throws:

IOException - if the input string is malformed

encrypt

public String encrypt(String str)

Produce a (base-64 encoded) encrypted version of a string. The first 22 characters of the result string are the base64-encoded IV (minus a terminal "=="). The remainder of the string is the base64-encoded ciphertext.

Parameters:

str - String to be encrypted

Returns:

an encoded, encrypted version of the given string

generateKey

public static String generateKey()

Generate a new, random key.

Returns:

the generated key, as a string containing a base64-encoding of the key bits.