io.getlime.security.powerauth.lib.generator

Class KeyGenerator

java.lang.Object

io.getlime.security.powerauth.lib.generator.KeyGenerator

public class KeyGenerator
extends Object

An implementation of a high-level key generator class. Keys are generated using elliptic curves (EC) and unless explicitly stated otherwise, they have 128b length.

Author:

Petr Dvorak

Constructor Summary

Constructors

Constructor and Description
KeyGenerator()

Method Summary

Modifier and Type	Method and Description
SecretKey	computeSharedKey(PrivateKey privateKey, PublicKey publicKey) Computes a pre-shared key for given private key and public key (ECDH).
byte[]	convert32Bto16B(byte[] original) Convert 32B byte long array to 16B long array by applying xor between first half and second half values.
SecretKey	deriveSecretKey(SecretKey secret, long index) Derives a new secret key KEY_SHARED from a master secret key KEY_MASTER based on following KDF: BYTES = index, padded from left with 0x00, total 16 bytes KEY_SHARED[BYTES] = AES(BYTES, KEY_MASTER)
SecretKey	deriveSecretKeyFromPassword(String password, byte[] salt) Derive a long AES suitable key from a password and salt.
KeyPair	generateKeyPair() Generate a new ECDH key pair using P256r1 curve.
byte[]	generateRandomBytes(int len) Generate a new random byte array with given length.
SecretKey	generateRandomSecretKey() Generate a new random symmetric key.

Methods inherited from class java.lang.Object

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

Constructor Detail

KeyGenerator

public KeyGenerator()

Method Detail

generateKeyPair

public KeyPair generateKeyPair()

Generate a new ECDH key pair using P256r1 curve.

Returns:

A new key pair instance, or null in case of an error.

computeSharedKey

public SecretKey computeSharedKey(PrivateKey privateKey,
                                  PublicKey publicKey)
                           throws InvalidKeyException

Computes a pre-shared key for given private key and public key (ECDH).

Parameters:

privateKey - A private key.

publicKey - A public key.

Returns:

A new instance of the pre-shared key.

Throws:

InvalidKeyException - One of the provided keys are not valid keys.

convert32Bto16B

public byte[] convert32Bto16B(byte[] original)
                       throws IllegalArgumentException

Convert 32B byte long array to 16B long array by applying xor between first half and second half values.

Parameters:

original - Original byte array, 32B long.

Returns:

Result byte array, 16B long.

Throws:

IllegalArgumentException

generateRandomBytes

public byte[] generateRandomBytes(int len)

Generate a new random byte array with given length.

Parameters:

len - Number of random bytes to be generated.

Returns:

An array with len random bytes.

generateRandomSecretKey

public SecretKey generateRandomSecretKey()

Generate a new random symmetric key.

Returns:

A new instance of a symmetric key.

deriveSecretKey

public SecretKey deriveSecretKey(SecretKey secret,
                                 long index)

Derives a new secret key KEY_SHARED from a master secret key KEY_MASTER based on following KDF: BYTES = index, padded from left with 0x00, total 16 bytes KEY_SHARED[BYTES] = AES(BYTES, KEY_MASTER)

Parameters:

secret - A master shared key

index - An index of the key

Returns:

A new derived key from a master key with given index.

deriveSecretKeyFromPassword

public SecretKey deriveSecretKeyFromPassword(String password,
                                             byte[] salt)

Derive a long AES suitable key from a password and salt. Uses PBKDF with 10 000 iterations.

Parameters:

password - A password used for key derivation

salt - A salt used for key derivation

Returns:

A new secret key derived from the password.