org.bouncycastle.asn1.gm

Class SM9Cipher

java.lang.Object

org.bouncycastle.asn1.ASN1Object

org.bouncycastle.asn1.gm.SM9Cipher

All Implemented Interfaces:

ASN1Encodable, Encodable

public class SM9Cipher
extends ASN1Object

The SM9 public-key encryption ciphertext structure of GM/T 0080-2020 (the C1/C2/C3 values are defined by the encryption algorithm in GM/T 0044.4).

 SM9Cipher ::= SEQUENCE {
     enType  INTEGER,       -- data-encapsulation type (see below)
     C1      BIT STRING,    -- the point C1 = [r]Q_B of G1, uncompressed (0x04||x||y)
     C3      OCTET STRING,  -- the MAC value C3 (32 bytes)
     C2      OCTET STRING   -- the encapsulated message C2
 }
 

The field order and types (enType INTEGER, C1 BIT STRING, C3/C2 OCTET STRING) have been cross-checked against the GmSSL and gmsm (emmansun) reference implementations of GM/T 0080-2020. The GM/T 0080-2020 data-encapsulation type values are 0 = KDF stream cipher (XOR), 1 = SM4-ECB, 2 = SM4-CBC, 4 = SM4-OFB, 8 = SM4-CFB, and this type represents every one of them, so that a conformant ciphertext of any mode can be parsed and inspected. Which modes are implemented is a separate question, answered one layer up: Cipher.SM9 decrypts in the stream (EN_TYPE_STREAM) and SM4-ECB (EN_TYPE_SM4) modes and refuses a ciphertext whose enType is not the one it was configured for. The value is never taken as the mode to decrypt in.

C1 and C3 have a fixed size, 65 and 32 bytes, and both constructors hold them to it; C2 is as long as the encapsulated message makes it.

Field Summary

Fields

Modifier and Type	Field and Description
static int	EN_TYPE_SM4 GM/T 0080-2020 data-encapsulation type 1: SM4 in ECB mode.
static int	EN_TYPE_SM4_CBC GM/T 0080-2020 data-encapsulation type 2: SM4 in CBC mode (not implemented by Cipher.SM9).
static int	EN_TYPE_SM4_CFB GM/T 0080-2020 data-encapsulation type 8: SM4 in CFB mode (not implemented by Cipher.SM9).
static int	EN_TYPE_SM4_OFB GM/T 0080-2020 data-encapsulation type 4: SM4 in OFB mode (not implemented by Cipher.SM9).
static int	EN_TYPE_STREAM GM/T 0080-2020 data-encapsulation type 0: the KDF-based stream cipher (XOR).

Constructor Summary

Constructors

Constructor and Description
SM9Cipher(int enType, byte[] c1, byte[] c3, byte[] c2)

Method Summary

Modifier and Type	Method and Description
byte[]	getC1()
byte[]	getC2()
byte[]	getC3()
int	getEnType()
static SM9Cipher	getInstance(java.lang.Object o)
ASN1Primitive	toASN1Primitive() Method providing a primitive representation of this object suitable for encoding.

Methods inherited from class org.bouncycastle.asn1.ASN1Object

encodeTo, encodeTo, equals, getEncoded, getEncoded, hasEncodedTagValue, hashCode

Methods inherited from class java.lang.Object

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

Field Detail

EN_TYPE_STREAM

public static final int EN_TYPE_STREAM

GM/T 0080-2020 data-encapsulation type 0: the KDF-based stream cipher (XOR).

See Also:

Constant Field Values

EN_TYPE_SM4

public static final int EN_TYPE_SM4

GM/T 0080-2020 data-encapsulation type 1: SM4 in ECB mode.

See Also:

Constant Field Values

EN_TYPE_SM4_CBC

public static final int EN_TYPE_SM4_CBC

GM/T 0080-2020 data-encapsulation type 2: SM4 in CBC mode (not implemented by Cipher.SM9).

See Also:

Constant Field Values

EN_TYPE_SM4_OFB

public static final int EN_TYPE_SM4_OFB

GM/T 0080-2020 data-encapsulation type 4: SM4 in OFB mode (not implemented by Cipher.SM9).

See Also:

Constant Field Values

EN_TYPE_SM4_CFB

public static final int EN_TYPE_SM4_CFB

GM/T 0080-2020 data-encapsulation type 8: SM4 in CFB mode (not implemented by Cipher.SM9).

See Also:

Constant Field Values

Constructor Detail

SM9Cipher

public SM9Cipher(int enType,
                 byte[] c1,
                 byte[] c3,
                 byte[] c2)

Method Detail

getInstance

public static SM9Cipher getInstance(java.lang.Object o)

getEnType

public int getEnType()

getC1

public byte[] getC1()

getC3

public byte[] getC3()

getC2

public byte[] getC2()

toASN1Primitive

public ASN1Primitive toASN1Primitive()

Description copied from class: ASN1Object

Method providing a primitive representation of this object suitable for encoding.

Specified by:

toASN1Primitive in interface ASN1Encodable

Specified by:

toASN1Primitive in class ASN1Object

Returns:

a primitive representation of this object.