net.i2p.crypto

Class AESEngine

java.lang.Object

net.i2p.crypto.AESEngine

Direct Known Subclasses:

CryptixAESEngine

public class AESEngine
extends Object

Abstract base class for AES cipher operations in I2P. This class provides the interface and common functionality for AES encryption and decryption operations. The base implementation contains placeholder methods that log warnings when called. The actual AES implementation is provided by CryptixAESEngine which extends this class.

This design pattern allows for:

• Consistent API across different AES implementations
• Graceful fallback when AES is unavailable
• Easy swapping of underlying AES providers

See Also:

CryptixAESEngine

Field Summary

Fields

Modifier and Type	Field and Description
protected I2PAppContext	_context I2P application context
protected Log	_log Logger instance

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AESEngine(I2PAppContext ctx) Constructor for subclasses.

Method Summary

Modifier and Type	Method and Description
void	decrypt(byte[] payload, int payloadIndex, byte[] out, int outIndex, SessionKey sessionKey, byte[] iv, int length) Decrypt the data with the session key
void	decrypt(byte[] payload, int payloadIndex, byte[] out, int outIndex, SessionKey sessionKey, byte[] iv, int ivOffset, int length) Decrypt the data with the session key.
void	decryptBlock(byte[] payload, int inIndex, SessionKey sessionKey, byte[] rv, int outIndex) This just copies payload to rv, see extension for the real thing.
void	encrypt(byte[] payload, int payloadIndex, byte[] out, int outIndex, SessionKey sessionKey, byte[] iv, int length) Encrypt the payload with the session key
void	encrypt(byte[] payload, int payloadIndex, byte[] out, int outIndex, SessionKey sessionKey, byte[] iv, int ivOffset, int length) Encrypt payload with session key.
void	encryptBlock(byte[] payload, int inIndex, SessionKey sessionKey, byte[] out, int outIndex) This just copies payload to out, see extension for the real thing.
static byte[]	getPadding(I2PAppContext context, int curSize, long minPaddedSize) Return random bytes for padding the data to a mod 16 size so that it is at least minPaddedSize Public for ElGamalAESEngine.
static int	getPaddingSize(int curSize, long minPaddedSize) Return size for padding the data to a mod 16 size so that it is at least minPaddedSize Public for ElGamalAESEngine.

Methods inherited from class java.lang.Object

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

Field Detail

_context

protected final I2PAppContext _context

I2P application context

_log

protected final Log _log

Logger instance

Constructor Detail

AESEngine

protected AESEngine(I2PAppContext ctx)

Constructor for subclasses.

Parameters:

ctx - I2P application context

Method Detail

decrypt

public void decrypt(byte[] payload,
                    int payloadIndex,
                    byte[] out,
                    int outIndex,
                    SessionKey sessionKey,
                    byte[] iv,
                    int length)

Decrypt the data with the session key

Parameters:

payload - data to be decrypted

payloadIndex - index into the payload to start decrypting

out - where to store the cleartext

outIndex - where in out to start writing

sessionKey - private session key to decrypt to

iv - IV for CBC

length - how much data to decrypt

decrypt

public void decrypt(byte[] payload,
                    int payloadIndex,
                    byte[] out,
                    int outIndex,
                    SessionKey sessionKey,
                    byte[] iv,
                    int ivOffset,
                    int length)

Decrypt the data with the session key. This just copies payload to out, see extension for the real thing.

Parameters:

payload - data to be decrypted

payloadIndex - index into the payload to start decrypting

out - where to store the cleartext

outIndex - where in out to start writing

sessionKey - private session key to decrypt to

iv - IV for CBC

ivOffset - offset into IV

length - how much data to decrypt

decryptBlock

public void decryptBlock(byte[] payload,
                         int inIndex,
                         SessionKey sessionKey,
                         byte[] rv,
                         int outIndex)

This just copies payload to rv, see extension for the real thing.

Parameters:

payload - encrypted data

inIndex - starting index in payload

sessionKey - private session key

rv - output buffer

outIndex - starting index in output

encrypt

public void encrypt(byte[] payload,
                    int payloadIndex,
                    byte[] out,
                    int outIndex,
                    SessionKey sessionKey,
                    byte[] iv,
                    int length)

Encrypt the payload with the session key

Parameters:

payload - data to be encrypted

payloadIndex - index into the payload to start encrypting

out - where to store the result

outIndex - where in out to start writing

sessionKey - private esession key to encrypt to

iv - IV for CBC, must be 16 bytes

length - how much data to encrypt

encrypt

public void encrypt(byte[] payload,
                    int payloadIndex,
                    byte[] out,
                    int outIndex,
                    SessionKey sessionKey,
                    byte[] iv,
                    int ivOffset,
                    int length)

Encrypt payload with session key. This just copies payload to out, see extension for the real thing.

Parameters:

payload - data to be encrypted

payloadIndex - index into payload to start encrypting

out - where to store result

outIndex - where in out to start writing

sessionKey - private session key to encrypt to

iv - IV for CBC

ivOffset - offset into IV

length - how much data to encrypt

encryptBlock

public void encryptBlock(byte[] payload,
                         int inIndex,
                         SessionKey sessionKey,
                         byte[] out,
                         int outIndex)

This just copies payload to out, see extension for the real thing.

Parameters:

payload - data to encrypt

inIndex - starting index in payload

sessionKey - unused

out - output buffer

outIndex - starting index in output

getPadding

public static final byte[] getPadding(I2PAppContext context,
                                      int curSize,
                                      long minPaddedSize)

Return random bytes for padding the data to a mod 16 size so that it is at least minPaddedSize Public for ElGamalAESEngine. Not a public API, not for external use.

Parameters:

context - I2P application context

curSize - current data size

minPaddedSize - minimum padded size

Returns:

padding bytes

getPaddingSize

public static final int getPaddingSize(int curSize,
                                       long minPaddedSize)

Return size for padding the data to a mod 16 size so that it is at least minPaddedSize Public for ElGamalAESEngine. Not a public API, not for external use.

Parameters:

curSize - current data size

minPaddedSize - minimum padded size

Returns:

padding size required