Package com.icodici.crypto

Class SymmetricKey

java.lang.Object

com.icodici.crypto.AbstractKey

com.icodici.crypto.SymmetricKey

All Implemented Interfaces:

KeyMatcher, java.io.Serializable, net.sergeych.tools.Bindable, net.sergeych.tools.Hashable

public class SymmetricKey
extends AbstractKey
implements java.io.Serializable, net.sergeych.tools.Hashable

Symmetric key: main interface to the symmetric cipher used in attesta. This implementation uses AES256 in CRT mode with IV to encrypt / decrypt. To change it, derive your class and simply override getCipher().

The cipher set and HMAC method maight be extended, using this class guaranteees compatibility.

Created by sergeych on 04/06/16.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	SymmetricKey.AuthenticationFailed	Exception raised by the SymmetricKey.EtaDecryptingStream when HMAC verification failed or other situations of the kind.
class	SymmetricKey.EtaDecryptingStream	Read and decrypt AE (EtA) stream.
class	SymmetricKey.EtaEncryptingStream	Encrypts an AE (EtA) stream using Sha256-based HMAC.

Nested classes/interfaces inherited from interface net.sergeych.tools.Hashable

net.sergeych.tools.Hashable.Error

Field Summary

Fields inherited from class com.icodici.crypto.AbstractKey

FINGERPRINT_SHA256, FINGERPRINT_SHA384, keyInfo, TYPE_PRIVATE, TYPE_PRIVATE_PASSWORD, TYPE_PRIVATE_PASSWORD_V2, TYPE_PUBLIC

Constructor Summary

Constructors

Constructor	Description
SymmetricKey()	Create random symmetric key (AES256, CTR)
SymmetricKey(byte[] key)
SymmetricKey(byte[] key, KeyInfo keyInfo)

Method Summary

Modifier and Type	Method	Description
byte[]	decrypt(byte[] ciphertext)
java.io.InputStream	decryptStream(java.io.InputStream inputStream)
byte[]	encrypt(byte[] plaintext)
java.io.OutputStream	encryptStream(java.io.OutputStream outputStream)
boolean	equals(java.lang.Object obj)
byte[]	etaDecrypt(byte[] data)	Decrypt data using AE (EtA) with SHA256-based HMAC.
SymmetricKey.EtaDecryptingStream	etaDecryptStream(java.io.InputStream in)	Decrypt some stream on the fly using AE (EtA) and SHA256-based HMAC.
byte[]	etaEncrypt(byte[] data)	Encrypt data suing AE (EtA) with HMAC based on SHA256.
SymmetricKey.EtaEncryptingStream	etaEncryptStream(java.io.OutputStream out)	Encrypt some stream on hte fly using AE (EtA) with SHA256-based HMAC.
byte[]	etaSign(byte[] data)	Rare case: HMAC-signing data without ebcrypting it.
static SymmetricKey	fromPassword(java.lang.String password, int rounds)
static SymmetricKey	fromPassword(java.lang.String password, int rounds, byte[] salt)
int	getBitStrength()
protected BlockCipher	getCipher()
byte[]	getKey()
int	getSize()
int	hashCode()
byte[]	pack()
void	setKey(byte[] key)
java.util.Map<java.lang.String,java.lang.Object>	toHash()
void	updateFromHash(java.util.Map<java.lang.String,java.lang.Object> hash)
static byte[]	xor(byte[] src, int value)

Methods inherited from class com.icodici.crypto.AbstractKey

address, asKeySource, canSign, createAnonymousId, fingerprint, fromBinder, getLongAddress, getPublicKey, getShortAddress, info, isMatchingKey, isMatchingKeyAddress, isPrivate, isPublic, matchAnonymousId, matchTag, matchType, packedInfo, packToBase64String, setTag, setTag, sign, sign, toBinder, toString, unpack, updateDigestWithKeyComponents, updateFrom, verify, verify, verify

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

SymmetricKey

public SymmetricKey()

Create random symmetric key (AES256, CTR)

SymmetricKey

public SymmetricKey(byte[] key)

SymmetricKey

public SymmetricKey(byte[] key,
                    KeyInfo keyInfo)

Method Detail

fromPassword

public static SymmetricKey fromPassword(java.lang.String password,
                                        int rounds)

fromPassword

public static SymmetricKey fromPassword(java.lang.String password,
                                        int rounds,
                                        byte[] salt)

setKey

public void setKey(byte[] key)

getKey

public byte[] getKey()

getBitStrength

public int getBitStrength()

getSize

public int getSize()

toHash

public java.util.Map<java.lang.String,java.lang.Object> toHash()
                                                              throws java.lang.IllegalStateException

Specified by:

toHash in interface net.sergeych.tools.Hashable

Throws:

java.lang.IllegalStateException

updateFromHash

public void updateFromHash(java.util.Map<java.lang.String,java.lang.Object> hash)
                    throws net.sergeych.tools.Hashable.Error

Specified by:

updateFromHash in interface net.sergeych.tools.Hashable

Throws:

net.sergeych.tools.Hashable.Error

getCipher

protected BlockCipher getCipher()

encrypt

public byte[] encrypt(byte[] plaintext)
               throws EncryptionError

Overrides:

encrypt in class AbstractKey

Throws:

EncryptionError

decrypt

public byte[] decrypt(byte[] ciphertext)
               throws EncryptionError

Overrides:

decrypt in class AbstractKey

Throws:

EncryptionError

encryptStream

public java.io.OutputStream encryptStream(java.io.OutputStream outputStream)
                                   throws java.io.IOException,
                                          EncryptionError

Throws:

java.io.IOException

EncryptionError

decryptStream

public java.io.InputStream decryptStream(java.io.InputStream inputStream)
                                  throws java.io.IOException,
                                         EncryptionError

Throws:

java.io.IOException

EncryptionError

etaEncryptStream

public SymmetricKey.EtaEncryptingStream etaEncryptStream(java.io.OutputStream out)
                                                  throws java.io.IOException,
                                                         EncryptionError

Encrypt some stream on hte fly using AE (EtA) with SHA256-based HMAC. Caller must call SymmetricKey.EtaEncryptingStream.end() or SymmetricKey.EtaEncryptingStream.close() in order to properly finish AE process. Note, to get the maximum security you should put some random sized random data in the file. As a variant, write some number N and then N random bytes. Have N also random. When reading, read N and skip N bytes first. Otherwise, use Boss streams to write structured data and put some random bytes in the beginning then skip it.

Parameters:

out - stream where to put encrypted data.

Returns:

encrpyting stream

Throws:

java.io.IOException

EncryptionError

etaDecryptStream

public SymmetricKey.EtaDecryptingStream etaDecryptStream(java.io.InputStream in)
                                                  throws java.io.IOException,
                                                         EncryptionError

Decrypt some stream on the fly using AE (EtA) and SHA256-based HMAC. Simply read the returned to the end stream. When it reaches the end, HMAC record will be extracted and checked, and the SymmetricKey.AuthenticationFailed will be thrown as need.

Parameters:

in - stream to decrypt

Returns:

stream with decrypted data.

Throws:

java.io.IOException

EncryptionError

etaEncrypt

public byte[] etaEncrypt(byte[] data)
                  throws EncryptionError

Encrypt data suing AE (EtA) with HMAC based on SHA256. It is advisory ro add some random-sized random data chunk (easiest is to add it to the beginning), or use Boss to serialize structored data and add random chunk somewhere. Make the hacker effor hopeless and silly ;) Keeping the right data size reveals some information on the package contents, just don't.

It uses IV-based CTR encryption, see encrypt(byte[]) for details.

Parameters:

data - to encrypt

Returns:

encrypted data.

Throws:

EncryptionError

etaSign

public byte[] etaSign(byte[] data)
               throws EncryptionError

Rare case: HMAC-signing data without ebcrypting it. Right now we use it only for testing, but if need can extends with verification of the plain data.

Parameters:

data - to sign

Returns:

data + HMAC (last 32 bytes)

Throws:

EncryptionError

etaDecrypt

public byte[] etaDecrypt(byte[] data)
                  throws EncryptionError,
                         SymmetricKey.AuthenticationFailed

Decrypt data using AE (EtA) with SHA256-based HMAC.

Parameters:

data - to decrypt

Returns:

decrypted data

Throws:

EncryptionError

SymmetricKey.AuthenticationFailed - if the authentication record does not match the data.

xor

public static byte[] xor(byte[] src,
                         int value)

pack

public byte[] pack()

Overrides:

pack in class AbstractKey

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object