AES-256

A program that uses AES-256 encryption and decryption for strings and files.

Configuration Settings

The configuration is expressed in JSON and is supplied by default in *config/config.json*. It can be overriden with a java system property, i.e. *-Dapp.configurationFile=config/config.json*

[options="header"]
|=======================
|Key                        |Value               |Description
|cipher                     |                    |The cipher section
|cipher:character-set       |UTF-8               |The character set to use for the cipher
|cipher:instance            |AES/CBC/PKCS5Padding|The instance class for the cipher
|salter                     |                    |The salter section
|salter:character-set       |UTF-8               |The character set to use for the salt
|salter:iterations          |3                   |The number of iterations to make
|password-minimum-length    |20                  |The minimum length of a password
|pbe-key-spec-iterations    |65536               |The number of iterations to make for the PBE key spec
|pbe-key-spec-key-length    |256                 |The key length for the PBE key spec
|secret-key-factory-instance|PBKDF2WithHmacSHA256|The instance class for the secret key factory
|secret-key-spec-algorithm  |AES                 |The algorithm for the secret key
|=======================

* A sample configuration file:
+
[source,json]
-----------------
{
    "cipher": {
        "character-set": "UTF-8",
        "instance": "AES/CBC/PKCS5Padding"
    },
    "salter": {
        "character-set": "UTF-8",
        "iterations": 3
    },
    "password-minimum-length": 20,
    "pbe-key-spec-iterations": 65536,
    "pbe-key-spec-key-length": 256,
    "secret-key-factory-instance": "PBKDF2WithHmacSHA256",
    "secret-key-spec-algorithm": "AES"
}
-----------------

Logging

Logging is achieved using the SLF4J facade over Logback. The logging configuration is supplied in config/logback.xml. It can be overriden with a java system property, i.e. -Dlogback.configurationFile=config/logback.xml

Command Line Usage

The command line synatx consists of an operation which is followed by one or more options. The possible case-insensitive operations are:

* Decrypt
* Encrypt
* Help

The options are described in the following table.

[options="header"]
|=======================
|Long Option  |Short Option|Description
|--help       |-h          |Display help (shown in an example below)
|--input-file |-i          |The name of the file to encrypt or decrypt
|--output-file|-o          |The name of the resulting encrypted or decrypted file
|--string     |-s          |The string to encrypt or decrypt
|--user       |-u          |The user identifier
|=======================

It is not permitted to include file options with string and vice versa. If files are to be handled then both input and output files are requred.

The user identifier will be prompted for at the console if not supplied as an option.

Also note that there is no command line option to provide a password. It will be prompted for at the console and has the
following requirements:

* At least one upper case character
* At least one lower case character
* At least one number or digit
* At least one special character, i.e. !@#$%^&*()-_+.,<>{}=[]\|~`/'\"?
* A minimum of twenty (20) chcracters in length

[source,text]
-----------------
usage: aes-256.main/net.jmp.aes256.Main <decrypt | encrypt | help>
 -h,--help                      Display this help message
 -i,--input-file <file-name>    Encrypt/Decrypt a file
 -o,--output-file <file-name>   Encrypted/Decrypted output file
 -s,--string <arg>              Encrypt/Decrypt a string
 -u,--user <user-id>            User identifier

-----------------

Ant Tasks

[options="header"] |======================= |Task |Description |copy-jar |For the developer it copies the jar to a target location |copy-config|For the developer it copies the config.json file to a target location |info |Set up to list the available tasks |=======================

Run Scripts

[options="header"]
|=======================
|Script|Decription
|decrypt.sh|Wraps the run script and passes the decrypt operation
|encrypt.sh|Wraps the run script and passes the encrypt operation
|run.sh    |The run script that invokes the Java main class
|=======================

Gradle JavaExec Tasks

[options="header"] |======================= |Task Name |Application Invocation |execNoArgs |No arguments |execHelpOption |-h |execHelpOperation |help |execDecryptStringNoUser|decrypt --string 7owHsJ9ihXMytkHB6WcnU1RH03r+ymuolCU2 |execDecryptStringUser |decrypt --string 7owHsJ9ihXMytkHB6WcnU1RH03r+ymuolCU2 --user jonathanp62... |execDecryptFileNoUser |decrypt --input-file /usr/local/file.bin --output-file /usr/local/file.plain |execDecryptFileUser |decrypt --input-file /usr/local/file.bin --output-file /usr/local/file.plain --user jonathanp62... |execEncryptStringNoUser|encrypt --string The quick brown fox... |execEncryptStringUser |encrypt --string The quick brown fox... --user jonathanp62... |execEncryptFileNoUser |encrypt --input-file /usr/local/file.plain --output-file /usr/local/file.bin |execEncryptFileUser |encrypt --input-file /usr/local/file.plain --output-file /usr/local/file.bin --user jonathanp62... |execUnknown |unknown |execUnknownOnlyUser |unknown --user jonathanp62... |=======================

Current version: 1.0.0.