org.eclipse.californium.scandium.dtls.cipher

Class PseudoRandomFunction

java.lang.Object

org.eclipse.californium.scandium.dtls.cipher.PseudoRandomFunction

public final class PseudoRandomFunction
extends Object

The Pseudo Random Function as defined in TLS 1.2.

See Also:

RFC 5246

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	PseudoRandomFunction.Label

Method Summary

Methods

Modifier and Type	Method and Description
static byte[]	doPRF(Mac hmac, SecretKey secret, PseudoRandomFunction.Label label, byte[] seed) Does the pseudo random function as defined in RFC 5246.
static byte[]	doPRF(Mac hmac, SecretKey secret, PseudoRandomFunction.Label label, byte[] seed, int length) Does the pseudo random function as defined in RFC 5246.
static SecretKey	generateMasterSecret(Mac hmac, SecretKey premasterSecret, byte[] seed) Generate master secret.
static SecretKey	generatePremasterSecretFromPSK(SecretKey otherSecret, SecretKey pskSecret) The premaster secret is formed as follows: if the PSK is N octets long, concatenate a uint16 with the value N, N zero octets, a second uint16 with the value N, and the PSK itself.

Methods inherited from class java.lang.Object

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

Method Detail

doPRF

public static final byte[] doPRF(Mac hmac,
           SecretKey secret,
           PseudoRandomFunction.Label label,
           byte[] seed)

Does the pseudo random function as defined in RFC 5246.

Parameters:

hmac - MAC algorithm. e.g. HmacSHA256

secret - the secret to use for the secure hash function

label - the label to use for creating the original data. Uses the length from the label.

seed - the seed to use for creating the original data

Returns:

the expanded data

doPRF

public static final byte[] doPRF(Mac hmac,
           SecretKey secret,
           PseudoRandomFunction.Label label,
           byte[] seed,
           int length)

Does the pseudo random function as defined in RFC 5246.

Parameters:

hmac - MAC algorithm. e.g. HmacSHA256

secret - the secret to use for the secure hash function

label - the label to use for creating the original data

seed - the seed to use for creating the original data

length - the length of data to create

Returns:

the expanded data

generateMasterSecret

public static SecretKey generateMasterSecret(Mac hmac,
                             SecretKey premasterSecret,
                             byte[] seed)

Generate master secret.

Parameters:

hmac - MAC algorithm. e.g. HmacSHA256

premasterSecret - the secret to use for the secure hash function

seed - the seed to use for creating the original data

Returns:

the master secret

generatePremasterSecretFromPSK

public static SecretKey generatePremasterSecretFromPSK(SecretKey otherSecret,
                                       SecretKey pskSecret)

The premaster secret is formed as follows: if the PSK is N octets long, concatenate a uint16 with the value N, N zero octets, a second uint16 with the value N, and the PSK itself.

Parameters:

otherSecret - either is zeroes (plain PSK case) or comes from the EC Diffie-Hellman exchange (ECDHE_PSK).

pskSecret - PSK secret.

Returns:

byte array with generated premaster secret.

See Also:

RFC 4279