Class ChaChaSpec

java.lang.Object

zeroecho.core.alg.chacha.ChaChaSpec

All Implemented Interfaces:

ChaChaBaseSpec, Describable, ContextSpec

public final class ChaChaSpec
extends Object
implements ChaChaBaseSpec, Describable

ChaCha20 stream cipher specification

Immutable parameter set for configuring a ChaCha20 context. Provides an initial counter and an optional SymmetricHeaderCodec.

Fields

• initialCounter() - the initial block counter used when no counter is present in the context or header (must be non-negative). Default is 1, matching common practice.
• header() - optional codec for encoding/decoding a stream header that carries runtime parameters such as nonce and counter.

Construction

Use the fluent ChaChaSpec.Builder:

ChaChaSpec spec = ChaChaSpec.builder()
    .initialCounter(42)
    .header(new ChaChaHeaderCodec())
    .build();

Convenience factory

• chacha20(SymmetricHeaderCodec) returns a spec with initial counter 1 and the provided header codec.

Since:

1.0

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	ChaChaSpec.Builder	Fluent builder for ChaChaSpec.

Method Summary

Modifier and Type	Method	Description
static ChaChaSpec.Builder	builder()	Returns a new builder for constructing a ChaChaSpec.
static ChaChaSpec	chacha20(SymmetricHeaderCodec header)	Convenience factory for a ChaCha20 spec with counter = 1.
String	description()	Human-readable description of this spec.
SymmetricHeaderCodec	header()	Returns the optional header codec.
int	initialCounter()	Returns the configured initial counter.

Methods inherited from class Object

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

Method Details

builder

public static ChaChaSpec.Builder builder()

Returns a new builder for constructing a ChaChaSpec.

Returns:

fresh builder instance

chacha20

public static ChaChaSpec chacha20(SymmetricHeaderCodec header)

Convenience factory for a ChaCha20 spec with counter = 1.

Parameters:

header - optional header codec

Returns:

new spec instance

initialCounter

public int initialCounter()

Returns the configured initial counter.

Returns:

non-negative counter value

header

public SymmetricHeaderCodec header()

Returns the optional header codec.

Specified by:

header in interface ChaChaBaseSpec

Returns:

codec instance or null

description

public String description()

Human-readable description of this spec.

Specified by:

description in interface Describable

Returns:

string of the form "ChaCha20(counter=N)"