Package org.drasyl.crypto

Class Crypto

java.lang.Object

org.drasyl.crypto.Crypto

public class Crypto
extends Object

Field Summary

Fields

Modifier and Type	Field	Description
static SecureRandom	SRND

Method Summary

Modifier and Type	Method	Description
static byte[]	compressedKey(PrivateKey privkey)
static byte[]	compressedKey(PublicKey key)
static KeyPair	generateKeys()
static PrivateKey	getPrivateKeyFromBytes(byte[] privKey)
static PublicKey	getPublicKeyFromBytes(byte[] pubKey)
static KeyPair	makeKeyPair(byte[] compressedPrivate, byte[] compressedPublic)
static org.bouncycastle.jce.interfaces.ECPrivateKey	parseCompressedPrivateKey(byte[] compressedPrivateKey)
static org.bouncycastle.jce.interfaces.ECPublicKey	parseCompressedPublicKey(byte[] compressedPubKey)
static int	randomNumber(int bound)	Generates a random number with the static SecureRandom of this class.
static String	randomString(int entropy)	Generates a secure random HEX String with the given entropy of bytes.
static void	sign(PrivateKey key, Signable signable)	Signs the given signable with the Privatekey.
static byte[]	signMessage(PrivateKey key, byte[] message)
static boolean	verifySignature(byte[] compressedPublicKey, byte[] message, byte[] signature)
static boolean	verifySignature(PublicKey pubkey, byte[] message, byte[] signature)
static boolean	verifySignature(PublicKey publicKey, Signable content)

Methods inherited from class java.lang.Object

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

Field Detail

SRND

public static final SecureRandom SRND

Method Detail

generateKeys

public static KeyPair generateKeys()

makeKeyPair

public static KeyPair makeKeyPair(byte[] compressedPrivate,
                                  byte[] compressedPublic)
                           throws CryptoException

Throws:

CryptoException

getPublicKeyFromBytes

public static PublicKey getPublicKeyFromBytes(byte[] pubKey)
                                       throws CryptoException

Throws:

CryptoException

getPrivateKeyFromBytes

public static PrivateKey getPrivateKeyFromBytes(byte[] privKey)
                                         throws CryptoException

Throws:

CryptoException

parseCompressedPublicKey

public static org.bouncycastle.jce.interfaces.ECPublicKey parseCompressedPublicKey(byte[] compressedPubKey)
                                                                            throws CryptoException

Throws:

CryptoException

parseCompressedPrivateKey

public static org.bouncycastle.jce.interfaces.ECPrivateKey parseCompressedPrivateKey(byte[] compressedPrivateKey)
                                                                              throws CryptoException

Throws:

CryptoException

compressedKey

public static byte[] compressedKey(PublicKey key)
                            throws CryptoException

Throws:

CryptoException

compressedKey

public static byte[] compressedKey(PrivateKey privkey)
                            throws CryptoException

Throws:

CryptoException

sign

public static void sign(PrivateKey key,
                        Signable signable)
                 throws CryptoException

Signs the given signable with the Privatekey. This will also put the resulting signature into the Signable object

Parameters:

key - Key to use

signable - signature to create

Throws:

CryptoException - on failure

signMessage

public static byte[] signMessage(PrivateKey key,
                                 byte[] message)
                          throws CryptoException

Throws:

CryptoException

verifySignature

public static boolean verifySignature(byte[] compressedPublicKey,
                                      byte[] message,
                                      byte[] signature)

verifySignature

public static boolean verifySignature(PublicKey pubkey,
                                      byte[] message,
                                      byte[] signature)

verifySignature

public static boolean verifySignature(PublicKey publicKey,
                                      Signable content)

randomString

public static String randomString(int entropy)

Generates a secure random HEX String with the given entropy of bytes.

Recommendation:

• 4 byte for small sets
• 8 bytes for unique internal strings, e.g. hash tables
• 16 bytes for global uniqueness, e.g. auth token

You can also use the following probability table for the "Birthday problem", as a starting point for a suitable entropy size: Birthday problem probability table

Parameters:

entropy - entropy in bytes

Returns:

a secure random HEX String

randomNumber

public static int randomNumber(int bound)

Generates a random number with the static SecureRandom of this class. Avoids overhead of generating a new instance of SecureRandom.

Parameters:

bound - the upper bound (exclusive). Must be positive.

Returns:

the next pseudorandom, uniformly distributed int value between zero (inclusive) and bound (exclusive) from this random number generator's sequence