com.tencent.kona.sun.security.rsa

Class RSAPadding

java.lang.Object

com.tencent.kona.sun.security.rsa.RSAPadding

public final class RSAPadding
extends java.lang.Object

RSA padding and unpadding. The various PKCS#1 versions can be found in the IETF RFCs tracking the corresponding PKCS#1 standards. RFC 2313: PKCS#1 v1.5 RFC 2437: PKCS#1 v2.0 RFC 3447: PKCS#1 v2.1 RFC 8017: PKCS#1 v2.2 The format of PKCS#1 v1.5 padding is: 0x00 | BT | PS...PS | 0x00 | data...data where BT is the blocktype (1 or 2). The length of the entire string must be the same as the size of the modulus (i.e. 128 byte for a 1024 bit key). Per spec, the padding string must be at least 8 bytes long. That leaves up to (length of key in bytes) - 11 bytes for the data. OAEP padding was introduced in PKCS#1 v2.0 and is a bit more complicated and has a number of options. We support: . arbitrary hash functions ('Hash' in the specification), MessageDigest implementation must be available . MGF1 as the mask generation function . the empty string as the default value for label L and whatever specified in javax.crypto.spec.OAEPParameterSpec The algorithms (representations) are forwards-compatible: that is, the algorithm described in previous releases are in later releases. However, additional comments/checks/clarifications were added to the latter versions based on real-world experience (e.g. stricter v1.5 format checking.) Note: RSA keys should be at least 512 bits long

Since:

1.5

Field Summary

Fields

Modifier and Type	Field and Description
static int	PAD_BLOCKTYPE_1
static int	PAD_BLOCKTYPE_2
static int	PAD_NONE
static int	PAD_OAEP_MGF1

Method Summary

Modifier and Type	Method and Description
static RSAPadding	getInstance(int type, int paddedSize) Get a RSAPadding instance of the specified type.
static RSAPadding	getInstance(int type, int paddedSize, java.security.SecureRandom random) Get a RSAPadding instance of the specified type.
static RSAPadding	getInstance(int type, int paddedSize, java.security.SecureRandom random, javax.crypto.spec.OAEPParameterSpec spec) Get a RSAPadding instance of the specified type, which must be OAEP.
int	getMaxDataSize() Return the maximum size of the plaintext data that can be processed using this object.
byte[]	pad(byte[] data) Pad the data and return the padded block.
byte[]	pad(byte[] data, int ofs, int len) Pad the data and return the padded block.
byte[]	unpad(byte[] padded) Unpad the padded block and return the data.

Methods inherited from class java.lang.Object

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

Field Detail

PAD_BLOCKTYPE_1

public static final int PAD_BLOCKTYPE_1

See Also:

Constant Field Values

PAD_BLOCKTYPE_2

public static final int PAD_BLOCKTYPE_2

See Also:

Constant Field Values

PAD_NONE

public static final int PAD_NONE

See Also:

Constant Field Values

PAD_OAEP_MGF1

public static final int PAD_OAEP_MGF1

See Also:

Constant Field Values

Method Detail

getInstance

public static RSAPadding getInstance(int type,
                                     int paddedSize)
                              throws java.security.InvalidKeyException,
                                     java.security.InvalidAlgorithmParameterException

Get a RSAPadding instance of the specified type. Keys used with this padding must be paddedSize bytes long.

Throws:

java.security.InvalidKeyException

java.security.InvalidAlgorithmParameterException

getInstance

public static RSAPadding getInstance(int type,
                                     int paddedSize,
                                     java.security.SecureRandom random)
                              throws java.security.InvalidKeyException,
                                     java.security.InvalidAlgorithmParameterException

Get a RSAPadding instance of the specified type. Keys used with this padding must be paddedSize bytes long.

Throws:

java.security.InvalidKeyException

java.security.InvalidAlgorithmParameterException

getInstance

public static RSAPadding getInstance(int type,
                                     int paddedSize,
                                     java.security.SecureRandom random,
                                     javax.crypto.spec.OAEPParameterSpec spec)
                              throws java.security.InvalidKeyException,
                                     java.security.InvalidAlgorithmParameterException

Get a RSAPadding instance of the specified type, which must be OAEP. Keys used with this padding must be paddedSize bytes long.

Throws:

java.security.InvalidKeyException

java.security.InvalidAlgorithmParameterException

getMaxDataSize

public int getMaxDataSize()

Return the maximum size of the plaintext data that can be processed using this object.

pad

public byte[] pad(byte[] data)
           throws javax.crypto.BadPaddingException

Pad the data and return the padded block.

Throws:

javax.crypto.BadPaddingException

pad

public byte[] pad(byte[] data,
                  int ofs,
                  int len)
           throws javax.crypto.BadPaddingException

Pad the data and return the padded block.

Throws:

javax.crypto.BadPaddingException

unpad

public byte[] unpad(byte[] padded)
             throws javax.crypto.BadPaddingException

Unpad the padded block and return the data.

Throws:

javax.crypto.BadPaddingException