net.ME1312.SubServers.Host.Network

Class AES

java.lang.Object

net.ME1312.SubServers.Host.Network.AES

public final class AES
extends java.lang.Object

A class to perform password-based AES encryption and decryption in CBC mode. 128, 192, and 256-bit encryption are supported, provided that the latter two are permitted by the Java runtime's jurisdiction policy files.
The public interface for this class consists of the static methods encrypt(int, java.lang.String, java.io.InputStream, java.io.OutputStream) and decrypt(java.lang.String, java.io.InputStream, java.io.OutputStream), which encrypt and decrypt arbitrary streams of data, respectively.

Author:

dweymouth@gmail.com

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	AES.InvalidAESStreamException Thrown if an attempt is made to decrypt an invalid AES stream.
static class	AES.InvalidKeyLengthException Thrown if an attempt is made to encrypt a stream with an invalid AES key length.
static class	AES.InvalidPasswordException Thrown if an attempt is made to decrypt a stream with an incorrect password.
static class	AES.StrongEncryptionNotAvailableException Thrown if 192- or 256-bit AES encryption or decryption is attempted, but not available on the particular Java platform.

Constructor Summary

Constructors

Constructor and Description
AES()

Method Summary

Modifier and Type	Method and Description
static NamedContainer<java.lang.Integer,java.lang.String>	decrypt(java.lang.String password, byte[] input) Decrypts a stream of data that was encrypted by encrypt(int, java.lang.String, java.io.InputStream, java.io.OutputStream).
static int	decrypt(java.lang.String password, java.io.InputStream input, java.io.OutputStream output) Decrypts a stream of data that was encrypted by encrypt(int, java.lang.String, java.io.InputStream, java.io.OutputStream).
static void	encrypt(int keyLength, java.lang.String password, java.io.InputStream input, java.io.OutputStream output) Encrypts a stream of data.
static byte[]	encrypt(int keyLength, java.lang.String password, java.lang.String input) Encrypts a stream of data.

Methods inherited from class java.lang.Object

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

Constructor Detail

AES

public AES()

Method Detail

encrypt

public static void encrypt(int keyLength,
                           java.lang.String password,
                           java.io.InputStream input,
                           java.io.OutputStream output)
                    throws AES.InvalidKeyLengthException,
                           AES.StrongEncryptionNotAvailableException,
                           java.io.IOException

Encrypts a stream of data. The encrypted stream consists of a header followed by the raw AES data. The header is broken down as follows:

• keyLength: AES key length in bytes (valid for 16, 24, 32) (1 byte)
• salt: pseudorandom salt used to derive keys from password (16 bytes)
• authentication key (derived from password and salt, used to check validity of password upon decryption) (8 bytes)
• IV: pseudorandom AES initialization vector (16 bytes)

Parameters:

keyLength - key length to use for AES encryption (must be 128, 192, or 256)

password - password to use for encryption

input - an arbitrary byte stream to encrypt

output - stream to which encrypted data will be written

Throws:

AES.InvalidKeyLengthException - if keyLength is not 128, 192, or 256

AES.StrongEncryptionNotAvailableException - if keyLength is 192 or 256, but the Java runtime's jurisdiction policy files do not allow 192- or 256-bit encryption

java.io.IOException

encrypt

public static byte[] encrypt(int keyLength,
                             java.lang.String password,
                             java.lang.String input)
                      throws java.io.IOException,
                             AES.StrongEncryptionNotAvailableException,
                             AES.InvalidKeyLengthException

Encrypts a stream of data. The encrypted stream consists of a header followed by the raw AES data. The header is broken down as follows:

• keyLength: AES key length in bytes (valid for 16, 24, 32) (1 byte)
• salt: pseudorandom salt used to derive keys from password (16 bytes)
• authentication key (derived from password and salt, used to check validity of password upon decryption) (8 bytes)
• IV: pseudorandom AES initialization vector (16 bytes)

Parameters:

keyLength - key length to use for AES encryption (must be 128, 192, or 256)

password - password to use for encryption

input - an arbitrary string to encrypt

Returns:

string containing the encrypted data

Throws:

AES.InvalidKeyLengthException - if keyLength is not 128, 192, or 256

AES.StrongEncryptionNotAvailableException - if keyLength is 192 or 256, but the Java runtime's jurisdiction policy files do not allow 192- or 256-bit encryption

java.io.IOException

decrypt

public static int decrypt(java.lang.String password,
                          java.io.InputStream input,
                          java.io.OutputStream output)
                   throws AES.InvalidPasswordException,
                          AES.InvalidAESStreamException,
                          java.io.IOException,
                          AES.StrongEncryptionNotAvailableException

Decrypts a stream of data that was encrypted by encrypt(int, java.lang.String, java.io.InputStream, java.io.OutputStream).

Parameters:

password - the password used to encrypt/decrypt the stream

input - stream of encrypted data to be decrypted

output - stream to which decrypted data will be written

Returns:

the key length for the decrypted stream (128, 192, or 256)

Throws:

AES.InvalidPasswordException - if the given password was not used to encrypt the data

AES.InvalidAESStreamException - if the given input stream is not a valid AES-encrypted stream

AES.StrongEncryptionNotAvailableException - if the stream is 192 or 256-bit encrypted, and the Java runtime's jurisdiction policy files do not allow for AES-192 or 256

java.io.IOException

decrypt

public static NamedContainer<java.lang.Integer,java.lang.String> decrypt(java.lang.String password,
                                                                         byte[] input)
                                                                  throws java.io.IOException,
                                                                         AES.StrongEncryptionNotAvailableException,
                                                                         AES.InvalidAESStreamException,
                                                                         AES.InvalidPasswordException

Decrypts a stream of data that was encrypted by encrypt(int, java.lang.String, java.io.InputStream, java.io.OutputStream).

Parameters:

password - the password used to encrypt/decrypt the string

input - string of encrypted data to be decrypted

Returns:

the key length for the decrypted string (128, 192, or 256) and the string of decrypted data

Throws:

AES.InvalidPasswordException - if the given password was not used to encrypt the data

AES.InvalidAESStreamException - if the given input stream is not a valid AES-encrypted stream

AES.StrongEncryptionNotAvailableException - if the stream is 192 or 256-bit encrypted, and the Java runtime's jurisdiction policy files do not allow for AES-192 or 256

java.io.IOException