Interface SM9EncMasterPublicKey

All Superinterfaces:

AsymmetricKey, DEREncodablePREVIEW, Key, PublicKey, Serializable

public interface SM9EncMasterPublicKey
extends PublicKey

Interface for an SM9 (GM/T 0044) encryption master public key, the published root of the identity-based scheme.

Field Summary

Fields

Modifier and Type	Field	Description
static final byte	HID	The encryption private-key generation function identifier hid, 0x03 - the value the GM/T 0044.5-2016 Annex C/D worked examples publish for KEM and public-key encryption.
static final byte	HID_EXCHANGE	The key-exchange private-key generation function identifier hid, 0x02, as published by the Chinese edition of the GM/T 0044.5-2016 Annex B worked example (the official English edition of the same annex chose 0x03 - the KGC's published choice governs).

Fields inherited from interface PublicKey

serialVersionUID

Method Summary

Modifier and Type	Method	Description
PublicKey	getExchangeEphemeral(byte[] encoded)	Wrap a peer's key-exchange ephemeral value R, as received, for the final doPhase of KeyAgreement.SM9 - the encoding is the standard's 64-byte x || y form returned by the first doPhase on the peer's side.
PublicKey	getUserPublicKey(byte[] identity)	Return the public key of the user identified by identity: the key a sender encapsulates to.
PublicKey	getUserPublicKey(byte[] identity, byte hid)	Return the public key of the user identified by identity under an explicit hid - 0x03 for KEM / public-key encryption, 0x02 for key exchange; the KGC's published choice governs.

Methods inherited from interface AsymmetricKey

getParams

Methods inherited from interface Key

getAlgorithm, getEncoded, getFormat

Field Details

HID

static final byte HID

The encryption private-key generation function identifier hid, 0x03 - the value the GM/T 0044.5-2016 Annex C/D worked examples publish for KEM and public-key encryption. hid is not fixed by the standard: GM/T 0044.3-2016 defines it as the "identifier of the encryption private key generating function, denoted by one byte", chosen and published by the KGC. These are the two values the published GM/T 0044 examples use.

See Also:

• Constant Field Values

HID_EXCHANGE

static final byte HID_EXCHANGE

The key-exchange private-key generation function identifier hid, 0x02, as published by the Chinese edition of the GM/T 0044.5-2016 Annex B worked example (the official English edition of the same annex chose 0x03 - the KGC's published choice governs).

See Also:

• Constant Field Values

Method Details

getUserPublicKey

PublicKey getUserPublicKey(byte[] identity)

Return the public key of the user identified by identity: the key a sender encapsulates to. It is derived from the master public key and the identity alone, so any sender holding the published master public key can construct it - no certificate or KGC interaction is needed.

Parameters:

identity - the user's identity.

Returns:

the user's public key.

getUserPublicKey

PublicKey getUserPublicKey(byte[] identity,
 byte hid)

Return the public key of the user identified by identity under an explicit hid - 0x03 for KEM / public-key encryption, 0x02 for key exchange; the KGC's published choice governs.

Parameters:

identity - the user's identity.

hid - the private-key generation function identifier the KGC chose.

Returns:

the user's public key.

getExchangeEphemeral

PublicKey getExchangeEphemeral(byte[] encoded)

Wrap a peer's key-exchange ephemeral value R, as received, for the final doPhase of KeyAgreement.SM9 - the encoding is the standard's 64-byte x || y form returned by the first doPhase on the peer's side. A value that is not a point of G1, or is the point at infinity, is rejected here rather than reaching the pairing.

Parameters:

encoded - the peer's ephemeral value R, 64 bytes.

Returns:

the peer's ephemeral value, to pass to doPhase.