Class SM9Engine

java.lang.Object

org.bouncycastle.crypto.engines.SM9Engine

public class SM9Engine
extends Object

The SM9 public key encryption algorithm (GM/T 0044.4-2016, clause 7). Two data-encapsulation methods are supported: a KDF-based stream cipher (SM9Engine.Mode.STREAM) and SM4 in ECB mode with PKCS#7 padding (SM9Engine.Mode.SM4). The ciphertext is C = C1 || C3 || C2, where C1 is the G1 point [r]Q_B encoded as x||y, C3 = MAC(K2, C2), and C2 is the encapsulated message.

Usage follows the SM2Engine pattern: construct with the desired mode, init(true, new ParametersWithRandom(recipientKey, random)) to encrypt or init(false, userKey) to decrypt, then processBlock(byte[], int, int).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	SM9Engine.Mode	The GM/T 0044.4-2016 data-encapsulation method.

Constructor Summary

Constructors

Constructor	Description
SM9Engine()	Base constructor: SM4 data encapsulation (SM9Engine.Mode.SM4).
SM9Engine(SM9Engine.Mode mode)

Method Summary

Modifier and Type	Method	Description
int	getOutputSize(int inputLen)	Return an upper bound for the output produced by processBlock(byte[], int, int) on inputLen input bytes (exact for encryption and stream-mode decryption, an upper bound for SM4-mode decryption, whose padding length is unknown until removed).
void	init(boolean forEncryption, CipherParameters param)	Initialise the engine.
byte[]	processBlock(byte[] in, int inOff, int inLen)

Methods inherited from class Object

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

Constructor Details

SM9Engine

public SM9Engine()

Base constructor: SM4 data encapsulation (SM9Engine.Mode.SM4).

SM9Engine

public SM9Engine(SM9Engine.Mode mode)

Method Details

init

public void init(boolean forEncryption,
 CipherParameters param)

Initialise the engine. For encryption pass the recipient's SM9EncPublicKeyParameters, optionally wrapped in a ParametersWithRandom; for decryption pass the user's SM9EncPrivateKeyParameters.

getOutputSize

public int getOutputSize(int inputLen)

Return an upper bound for the output produced by processBlock(byte[], int, int) on inputLen input bytes (exact for encryption and stream-mode decryption, an upper bound for SM4-mode decryption, whose padding length is unknown until removed).

processBlock

public byte[] processBlock(byte[] in,
 int inOff,
 int inLen)
                    throws InvalidCipherTextException

Throws:

InvalidCipherTextException