Package com.icodici.crypto

Class KeyInfo

java.lang.Object

com.icodici.crypto.KeyInfo

public class KeyInfo
extends java.lang.Object

The object used to search suitable keys in the registry, distinct keys without compromising them, generate right keys from passwords and so on.

The KeyInfo is always included in the Capsule when used to encrypt data, so it has binary-effective packed representation, pack(), which can be used as a hashtag in the keyring, for example, wrapping it in the Bytes instance make possible to use it as a Map key and effectively find matching keys.

With symmetric keys special care should be taken to have a correct tag value, as it is not automatically generated, unlike with RSA keys, where it is 5 first bytes of Sha256() of the packed public key, which is almost always enough to identify it.

For password-generated keys all necessary information is kept to recreate key by the password which could be done easily with derivePassword(String).

Created by sergeych on 19.12.16.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	KeyInfo.Algorythm
static class	KeyInfo.PRF	Pseudo-random function to use with PBKDF2 to generate key from the password.

Constructor Summary

Constructors

Constructor	Description
KeyInfo(byte[] packedInfo)
KeyInfo(KeyInfo.Algorythm algorythm, byte[] tag)	Construct info for the algorythm with fixed key length, e.g.
KeyInfo(KeyInfo.Algorythm algorythm, byte[] tag, int keyLength)
KeyInfo(KeyInfo.PRF PRF, int rounds, byte[] salt, byte[] tag)	Construct PBKRF-based password key information.

Method Summary

Modifier and Type	Method	Description
SymmetricKey	derivePassword(java.lang.String password)
KeyInfo.Algorythm	getAlgorythm()
java.lang.String	getBase64Tag()
int	getKeyLength()
KeyInfo.PRF	getPRF()
int	getRounds()
byte[]	getSalt()
byte[]	getTag()
boolean	isPassword()
boolean	matchTag(KeyInfo keyInfo)	Return true if other key's tag is same or somehow match this key tag.
boolean	matchType(AbstractKey otherKey)	See matchType(KeyInfo) for details.
boolean	matchType(KeyInfo otherInfo)	Check that this key CAN DECRYPT other key.
byte[]	pack()
void	setTag(byte[] tag)
java.lang.String	toString()
AbstractKey	unpackKey(byte[] data)

Methods inherited from class java.lang.Object

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

Constructor Detail

KeyInfo

public KeyInfo(KeyInfo.Algorythm algorythm,
               byte[] tag,
               int keyLength)

KeyInfo

public KeyInfo(KeyInfo.Algorythm algorythm,
               byte[] tag)

Construct info for the algorythm with fixed key length, e.g. KeyInfo.Algorythm.AES256.

Parameters:

algorythm - should be one with fixed key length

tag - optional tag or null

KeyInfo

public KeyInfo(KeyInfo.PRF PRF,
               int rounds,
               byte[] salt,
               byte[] tag)

Construct PBKRF-based password key information.

Parameters:

PRF - hashing method PRF used in key derivation, see KeyInfo.PRF.

rounds -

salt -

tag -

KeyInfo

public KeyInfo(byte[] packedInfo)
        throws java.io.IOException

Throws:

java.io.IOException

Method Detail

getSalt

public byte[] getSalt()

matchType

public boolean matchType(KeyInfo otherInfo)

Check that this key CAN DECRYPT other key. The direction is important! It works with public/private and symmetric keys.

Parameters:

otherInfo - other key's info

Returns:

true if the decription is is possible, otherwise impossible.

matchType

public boolean matchType(AbstractKey otherKey)

See matchType(KeyInfo) for details.

Parameters:

otherKey -

Returns:

true if itherKey type matches this one's.

matchTag

public boolean matchTag(KeyInfo keyInfo)

Return true if other key's tag is same or somehow match this key tag. It means that the [robability of the successful decrryption is higher if this methods returns true.

Parameters:

keyInfo - other key info

Returns:

true if tags are matching/

setTag

public void setTag(byte[] tag)

getBase64Tag

public java.lang.String getBase64Tag()

isPassword

public boolean isPassword()

getTag

public byte[] getTag()

getRounds

public int getRounds()

getAlgorythm

public KeyInfo.Algorythm getAlgorythm()

getPRF

public KeyInfo.PRF getPRF()

getKeyLength

public int getKeyLength()

pack

public byte[] pack()

derivePassword

public SymmetricKey derivePassword(java.lang.String password)

unpackKey

public AbstractKey unpackKey(byte[] data)
                      throws EncryptionError

Throws:

EncryptionError

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object