Class KemCtxOpener

java.lang.Object

zeroecho.sdk.guard.KemCtxOpener

All Implemented Interfaces:

AutoCloseable, RecipientOpener

public final class KemCtxOpener
extends Object
implements RecipientOpener

Reusable opener for KEM:<algorithm>:GCM-WRAP entries.

Each applicable recipient entry receives a fresh decapsulation context from the explicit session. A failed same-algorithm entry therefore cannot consume the opener state needed by a later legitimate entry.

Constructor Summary

Constructors

Constructor	Description
KemCtxOpener(ZeroEchoSession session)	Creates an opener that derives contexts through the explicit session.

Method Summary

Modifier and Type	Method	Description
byte[]	tryOpen(String entryId, byte[] entryBlob, UnlockMaterial material)	Tries to recover the content-encryption key from the supplied recipient entry.

Methods inherited from class Object

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

Methods inherited from interface RecipientOpener

close

Constructor Details

KemCtxOpener

public KemCtxOpener(ZeroEchoSession session)

Creates an opener that derives contexts through the explicit session.

Parameters:

session - runtime configuration used for context creation

Throws:

NullPointerException - if session is null

Method Details

tryOpen

public byte[] tryOpen(String entryId,
 byte[] entryBlob,
 UnlockMaterial material)
               throws GeneralSecurityException,
IOException

Description copied from interface: RecipientOpener

Tries to recover the content-encryption key from the supplied recipient entry.

Specified by:

tryOpen in interface RecipientOpener

Parameters:

entryId - identifier string written by the sender; may be empty when labels are suppressed; used only as a routing hint

entryBlob - opaque bytes of the recipient entry produced by the matching Recipient; never null

material - unlocking material to use (for example, a private key or a password); never null

Returns:

a newly allocated byte array containing the recovered CEK, or null if this opener is not applicable

Throws:

GeneralSecurityException - if the entry appears applicable but cryptographic verification or unwrapping fails

IOException - if parsing the entry blob fails due to structural errors or truncated data