freenet.crypt

Class AEADOutputStream

java.lang.Object

java.io.OutputStream

java.io.FilterOutputStream

freenet.crypt.AEADOutputStream

All Implemented Interfaces:

java.io.Closeable, java.io.Flushable, java.lang.AutoCloseable

public class AEADOutputStream
extends java.io.FilterOutputStream

Uses bouncycastle's AEAD code. BC provides Cipher*Stream but they don't work with authenticating. FIXME This probably needs an internal buffer. Shouldn't be too inefficient provided that any short writes are buffered before they reach here though.

Field Summary

Fields

Modifier and Type	Field and Description
static int	AES_OVERHEAD

Fields inherited from class java.io.FilterOutputStream

out

Constructor Summary

Constructors

Constructor and Description
AEADOutputStream(java.io.OutputStream os, byte[] key, byte[] nonce, org.bouncycastle.crypto.BlockCipher hashCipher, org.bouncycastle.crypto.BlockCipher mainCipher) Create an encrypting, authenticating OutputStream.

Method Summary

Modifier and Type	Method and Description
void	close()
static AEADOutputStream	createAES(java.io.OutputStream os, byte[] key, java.security.SecureRandom random)
java.lang.String	toString()
void	write(byte[] buf)
void	write(byte[] buf, int offset, int length)
void	write(int b)

Methods inherited from class java.io.FilterOutputStream

flush

Methods inherited from class java.lang.Object

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

Field Detail

AES_OVERHEAD

public static final int AES_OVERHEAD

See Also:

Constant Field Values

Constructor Detail

AEADOutputStream

public AEADOutputStream(java.io.OutputStream os,
                        byte[] key,
                        byte[] nonce,
                        org.bouncycastle.crypto.BlockCipher hashCipher,
                        org.bouncycastle.crypto.BlockCipher mainCipher)
                 throws java.io.IOException

Create an encrypting, authenticating OutputStream. Will write the nonce to the stream.

Parameters:

os - The underlying OutputStream.

key - The encryption key.

nonce - The nonce. This serves the function of an IV. As a nonce, this MUST be unique. We will write it to the stream so the other side can pick it up, like an IV. Should generally be generated from a SecureRandom. The top bit must be 0, i.e. nonce[0] &= 0x7F.

mainCipher - The BlockCipher for encrypting data. E.g. AES; not a block mode. This will be used for encrypting a fairly large amount of data so could be any of the 3 BC AES impl's.

hashCipher - The BlockCipher for the final hash. E.g. AES, not a block mode. This will not be used very much so should be e.g. an AESLightEngine.

Throws:

java.io.IOException

Method Detail

write

public void write(int b)
           throws java.io.IOException

Overrides:

write in class java.io.FilterOutputStream

Throws:

java.io.IOException

write

public void write(byte[] buf)
           throws java.io.IOException

Overrides:

write in class java.io.FilterOutputStream

Throws:

java.io.IOException

write

public void write(byte[] buf,
                  int offset,
                  int length)
           throws java.io.IOException

Overrides:

write in class java.io.FilterOutputStream

Throws:

java.io.IOException

close

public void close()
           throws java.io.IOException

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Overrides:

close in class java.io.FilterOutputStream

Throws:

java.io.IOException

createAES

public static AEADOutputStream createAES(java.io.OutputStream os,
                                         byte[] key,
                                         java.security.SecureRandom random)
                                  throws java.io.IOException

Throws:

java.io.IOException

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object