java.lang.Object
- es.gob.jmulticard.jse.provider.rsacipher.RSAPadding

```
final class RSAPadding
extends java.lang.Object
```
Utilidad para la aplicación y la retirada de rellenos RSA. The various PKCS#1 versions can be found in the EMC/RSA Labs web site, which is currently: http://www.emc.com/emc-plus/rsa-labs/index.htm or in the IETF RFCs derived from the above PKCS#1 standards. RFC 2313: v1.5 RFC 2437: v2.0 RFC 3447: v2.1 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 later 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	Description
`private static java.util.Map<java.lang.String,byte[]>`	`EMPTY_HASHES`
`private byte[]`	`lHash`
`private int`	`maxDataSize`	Tamaño máximo de los datos.
`private java.security.MessageDigest`	`md`
`private java.security.MessageDigest`	`mgfMd`
`(package private) static int`	`PAD_BLOCKTYPE_1`	Relleno PKCS#1 v1.5, blocktype 1 (firma).
`(package private) static int`	`PAD_BLOCKTYPE_2`	Relleno PKCS#1 v1.5, blocktype 2 (cifrado).
`(package private) static int`	`PAD_NONE`	Sin relleno.
`(package private) static int`	`PAD_OAEP_MGF1`	Relleno PKCS#1 v2.1 OAEP.
`private int`	`paddedSize`
`private java.security.SecureRandom`	`random`
`private int`	`type`

Constructor Summary

Constructors
Modifier	Constructor	Description
`private`	`RSAPadding(int paddingType, int sizeAfterPadding, java.security.SecureRandom randomSrc, javax.crypto.spec.OAEPParameterSpec spec)`	Constructor interno.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`(package private) static RSAPadding`	`createInstance(int type, int paddedSize, java.security.SecureRandom random)`	Get a RSAPadding instance of the specified type.
`(package private) static RSAPadding`	`createInstance(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.
`private static byte[]`	`getInitialHash(java.security.MessageDigest md, byte[] digestInput)`	Return the value of the digest using the specified message digest `md` and the digest input `digestInput`.
`(package private) int`	`getMaxDataSize()`	Return the maximum size of the plaintext data that can be processed using this object.
`private void`	`mgf1(byte[] seed, int seedOfs, int seedLen, byte[] out, int outOffset, int maskLength)`	Compute MGF1 using mgfMD as the message digest.
`(package private) byte[]`	`pad(byte[] data)`	Pad the data and return the padded block.
`(package private) byte[]`	`pad(byte[] data, int ofs, int len)`	Rellena los datos.
`private byte[]`	`padOaep(byte[] message)`	PKCS#1 v2.0 OAEP padding (MGF1).
`private byte[]`	`padV15(byte[] data)`	PKCS#1 v1.5 padding (blocktype 1 and 2).
`(package private) byte[]`	`unpad(byte[] padded)`	Unpad the padded block and return the data.
`private byte[]`	`unpadOAEP(byte[] padded)`	PKCS#1 v2.1 OAEP unpadding (MGF1).
`private byte[]`	`unpadV15(byte[] padded)`	PKCS#1 v1.5 unpadding (blocktype 1 (signature) and 2 (encryption)).

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

PAD_BLOCKTYPE_1
```
static final int PAD_BLOCKTYPE_1
```
Relleno PKCS#1 v1.5, blocktype 1 (firma).

See Also:

Constant Field Values

PAD_BLOCKTYPE_2
```
static final int PAD_BLOCKTYPE_2
```
Relleno PKCS#1 v1.5, blocktype 2 (cifrado).

See Also:

Constant Field Values

PAD_NONE
```
static final int PAD_NONE
```
Sin relleno. Con este tipo la clase no hace nada.

See Also:

Constant Field Values

PAD_OAEP_MGF1
```
static final int PAD_OAEP_MGF1
```
Relleno PKCS#1 v2.1 OAEP.

See Also:

Constant Field Values

type
```
private final int type
```

paddedSize
```
private final int paddedSize
```

random

private java.security.SecureRandom random

maxDataSize
```
private final int maxDataSize
```
Tamaño máximo de los datos.

md
```
private java.security.MessageDigest md
```

mgfMd

private java.security.MessageDigest mgfMd

lHash
```
private byte[] lHash
```

EMPTY_HASHES

private static final java.util.Map<java.lang.String,byte[]> EMPTY_HASHES

Constructor Detail

RSAPadding

private RSAPadding(int paddingType,
                   int sizeAfterPadding,
                   java.security.SecureRandom randomSrc,
                   javax.crypto.spec.OAEPParameterSpec spec)
            throws java.security.InvalidKeyException,
                   java.security.InvalidAlgorithmParameterException

Constructor interno.

Throws:: java.security.InvalidKeyException; java.security.InvalidAlgorithmParameterException

Method Detail
- createInstance
```
static RSAPadding createInstance(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
- createInstance
```
static RSAPadding createInstance(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
- getInitialHash
```
private static byte[] getInitialHash(java.security.MessageDigest md,
                                     byte[] digestInput)
```
  Return the value of the digest using the specified message digest md and the digest input digestInput. if digestInput is null or 0-length, zero length is used to generate the initial digest. Note: the md object must be in reset state
- getMaxDataSize
```
int getMaxDataSize()
```
  Return the maximum size of the plaintext data that can be processed using this object.
- pad
```
byte[] pad(byte[] data,
           int ofs,
           int len)
    throws javax.crypto.BadPaddingException
```
  Rellena los datos. Pad the data and return the padded block.
  
  Throws:
  
  javax.crypto.BadPaddingException
- pad
```
byte[] pad(byte[] data)
    throws javax.crypto.BadPaddingException
```
  Pad the data and return the padded block.
  
  Throws:
  
  javax.crypto.BadPaddingException
- unpad
```
byte[] unpad(byte[] padded)
      throws javax.crypto.BadPaddingException
```
  Unpad the padded block and return the data.
  
  Throws:
  
  javax.crypto.BadPaddingException
- padV15
```
private byte[] padV15(byte[] data)
```
  PKCS#1 v1.5 padding (blocktype 1 and 2).
- unpadV15
```
private byte[] unpadV15(byte[] padded)
                 throws javax.crypto.BadPaddingException
```
  PKCS#1 v1.5 unpadding (blocktype 1 (signature) and 2 (encryption)). Note that we want to make it a constant-time operation
  
  Throws:
  
  javax.crypto.BadPaddingException
- padOaep
```
private byte[] padOaep(byte[] message)
                throws javax.crypto.BadPaddingException
```
  PKCS#1 v2.0 OAEP padding (MGF1). Paragraph references refer to PKCS#1 v2.1 (June 14, 2002)
  
  Throws:
  
  javax.crypto.BadPaddingException
- unpadOAEP
```
private byte[] unpadOAEP(byte[] padded)
                  throws javax.crypto.BadPaddingException
```
  PKCS#1 v2.1 OAEP unpadding (MGF1).
  
  Throws:
  
  javax.crypto.BadPaddingException
- mgf1
```
private void mgf1(byte[] seed,
                  int seedOfs,
                  int seedLen,
                  byte[] out,
                  int outOffset,
                  int maskLength)
           throws javax.crypto.BadPaddingException
```
  Compute MGF1 using mgfMD as the message digest. Note that we combine MGF1 with the XOR operation to reduce data copying. We generate maskLen bytes of MGF1 from the seed and XOR it into out[] starting at outOfs;
  
  Throws:
  
  javax.crypto.BadPaddingException

Class RSAPadding

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

PAD_BLOCKTYPE_1

PAD_BLOCKTYPE_2

PAD_NONE

PAD_OAEP_MGF1

type

paddedSize

random

maxDataSize

md

mgfMd

lHash

EMPTY_HASHES

Constructor Detail

RSAPadding

Method Detail

createInstance

createInstance

getInitialHash

getMaxDataSize

pad

pad

unpad

padV15

unpadV15

padOaep

unpadOAEP

mgf1