Module com.github.glusk.srp6_variables

Package com.github.glusk.srp6_variables

Interface SRP6IntegerVariable

All Known Implementing Classes:

AbstractSRP6IntegerVariable, SRP6ClientPublicKey, SRP6ClientSharedSecret, SRP6CustomIntegerVariable, SRP6Multiplier, SRP6PrivateKey, SRP6RandomEphemeral, SRP6ScramblingParameter, SRP6ServerPublicKey, SRP6ServerSharedSecret, SRP6Verifier

public interface SRP6IntegerVariable

An SRP-6 Integer Variable.

Objects that implement this interface represent SRP-6 integer variables. The full list of SRP-6 variables can be found in the package docs.

Mapping between integers and byte sequences

RFC2945 specifies a mapping (which RFC5054 follows) between byte sequences and integers:

...
An n-byte string S can be converted to an integer as follows:
i = S[n-1] + 256 * S[n-2] + 256^2 * S[n-3] + ... + 256^(n-1) * S[0]
...

Although the above mapping assumes big-endian byte order, objects implementing this interface must provide a little-endian representation as well. SRP-6 Integer Variables can be viewed both as little and big-endian byte sequences and it is up to the protocol implementor which representation to use.

Method Summary

Modifier and Type	Method	Description
default BigInteger	asNonNegativeBigInteger()	Returns this SRP-6 Integer Variable as a non-negative BigInteger.
Bytes	bytes(ByteOrder preferredOrder)	Returns this SRP-6 Integer Variable as a byte sequence in the preferred byte order.
default Bytes	bytes(ByteOrder preferredOrder, int length)	Returns a new byte sequence as a zero-padded result of this.bytes(preferredOrder).
boolean	equals(Object obj)	Compares the specified object with this SRP-6 Integer Variable for equality.
int	hashCode()	Returns the hash code value for this SRP-6 Integer Variable.

Method Detail

bytes

Bytes bytes(ByteOrder preferredOrder)

Returns this SRP-6 Integer Variable as a byte sequence in the preferred byte order.

The representation returned must be minimal. That is, all leading (or trailing, depending on the preferredOrder) zero bytes have to be trimmed.

Number zero is hence defined as an empty byte sequence.

Parameters:

preferredOrder - the preferred byte order of the byte sequence that represents this SRP-6 Integer Variable

Returns:

the byte sequence that represents this SRP-6 Integer Variable in the preferred byte order

bytes

default Bytes bytes(ByteOrder preferredOrder,
                    int length)
             throws SRP6PaddingException

Returns a new byte sequence as a zero-padded result of this.bytes(preferredOrder).

If preferredOrder equals to ByteOrder.BIG_ENDIAN, the sequence gets padded from the front, otherwise from the back.

Parameters:

preferredOrder - the preferred byte order of the byte sequence that represents this SRP-6 Integer Variable

length - the length of the zero-padded byte sequence to return

Returns:

a new zero-padded byte sequence that represents this SRP-6 Integer Variable in the preferred byte order

Throws:

SRP6PaddingException - if length is less than the length of the sequence returned by this.bytes(preferredOrder)

asNonNegativeBigInteger

default BigInteger asNonNegativeBigInteger()

Returns this SRP-6 Integer Variable as a non-negative BigInteger.

This method call is equivalent to:

 new BigInteger(1, bytes(ByteOrder.BIG_ENDIAN).asArray())
 

Returns:

this SRP-6 Integer Variable as a non-negative BigInteger

equals

boolean equals(Object obj)

Compares the specified object with this SRP-6 Integer Variable for equality.

Returns true if and only if the specified object is also an SRP-6 Integer Variable and both SRP-6 Integer Variables map to the same byte sequence. The mapping provided by bytes(ByteOrder) must be used.

Overrides:

equals in class Object

Parameters:

obj - the object to be compared for equality with this SRP-6 Integer Variable

Returns:

true if the specified object is equal to this SRP-6 Integer Variable

hashCode

int hashCode()

Returns the hash code value for this SRP-6 Integer Variable.

The hash code of an SRP-6 Integer Variable has to obey the general contract of Object.hashCode(). That is, if two SRP-6 Integer Variables are equal, then they must have the same hash code.

Overrides:

hashCode in class Object

Returns:

the hash code value for this SRP-6 Integer Variable