SHOW Signed

net.rim.device.api.crypto
Class OAEPUnformatterEngine

java.lang.Object
  |
  +--net.rim.device.api.crypto.OAEPUnformatterEngine

All Implemented Interfaces:

BlockUnformatterEngine

public final class OAEPUnformatterEngine

extends Object

implements BlockUnformatterEngine

Referenced from site http://www.rsasecurity.com/rsalabs/faq/7-10.html.

Optimal Asymmetric Encryption Padding (OAEP) is a method for encoding messages developed by Mihir Bellare and Phil Rogaway [BR94]. The technique of encoding a message with OAEP and then encrypting it with RSA is provably secure in the random oracle model. Informally, this means that if hash functions are truly random, then an adversary who can recover such a message must be able to break RSA.

An OAEP encoded message consists of a ``masked data'' string concatenated with a ``masked random number''. In the simplest form of OAEP, the masked data is formed by taking the XOR of the plaintext message M and the hash G of a random string r. The masked random number is the XOR of r with the hash H of the masked data. The input to the RSA encryption function is then: [M XOR G(r)] || [r XOR H(M XOR G(r))]

Often, OAEP is used to encode small items such as keys. There are other variations on OAEP (differing only slightly from the above) that include a feature called ``plaintext-awareness''. This means that to construct a valid OAEP encoded message, an adversary must know the original plaintext. To accomplish this, the plaintext message M is first padded (for example, with a string of zeroes) before the masked data is formed. OAEP is supported in the ANSI X9.44, IEEE P1363 and SET standards.

For a code sample using the OAEP unformatter engine, click here.

Category:

Signed: This element is only accessible by signed clients. If you intend to use this element, please contact RIM to establish the necessary agreements that will allow you to have your COD files signed. Signing is only required for use on the device, development under the JDE can occur without signing the CODs.

Since:

JDE 3.6.0

See Also:

OAEPFormatterEngine

Constructor Summary

	OAEPUnformatterEngine(PrivateKeyDecryptorEngine engine) Creates an OAEPUnformatterEngine object based upon the given decryptor engine, as well as the SHA-1 digest algorithm.
	OAEPUnformatterEngine(PrivateKeyDecryptorEngine engine, byte[] parameters) Creates an OAEPUnformatterEngine object based upon the given decryptor engine, as well as the SHA-1 digest algorithm, and the given parameters.
	OAEPUnformatterEngine(PrivateKeyDecryptorEngine engine, Digest digest) Creates an OAEPUnformatterEngine object based upon the given decryptor engine and digest algorithm.
	OAEPUnformatterEngine(PrivateKeyDecryptorEngine engine, Digest digest, byte[] parameters) Creates an OAEPUnformatterEngine object based upon the given decryptor engine, digest algorithm and parameters.

Method Summary

	int	decryptAndUnformat(byte[] input, int inputOffset, byte[] output, int outputOffset)
	int	decryptAndUnformat(byte[] input, int inputOffset, byte[] output, int outputOffset, boolean lastBlock)
	String	getAlgorithm() Returns the name of the algorithm used, ie PublicKeyEncryptorEngine.getAlgorithm() + "_OAEP".
	int	getInputBlockLength()
	int	getOutputBlockLength()

Methods inherited from class java.lang.Object

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

Constructor Detail

OAEPUnformatterEngine

public OAEPUnformatterEngine(PrivateKeyDecryptorEngine engine)

Creates an OAEPUnformatterEngine object based upon the given decryptor engine, as well as the SHA-1 digest algorithm.

Parameters:

engine - The PrivateKeyDecryptorEngine used to decrypt the formatted message.

Since:

JDE 3.6.0

Category:

Signed: This element is only accessible by signed clients. If you intend to use this element, please contact RIM to establish the necessary agreements that will allow you to have your COD files signed. Signing is only required for use on the device, development under the JDE can occur without signing the CODs.

OAEPUnformatterEngine

public OAEPUnformatterEngine(PrivateKeyDecryptorEngine engine,
                             byte[] parameters)

Creates an OAEPUnformatterEngine object based upon the given decryptor engine, as well as the SHA-1 digest algorithm, and the given parameters.

Parameters:

engine - The PrivateKeyDecryptorEngine used to decrypt the formatted message.

parameters - A byte array containing the parameters to be compared to those found in the formatted message.

Since:

JDE 3.6.0

Category:

Signed: This element is only accessible by signed clients. If you intend to use this element, please contact RIM to establish the necessary agreements that will allow you to have your COD files signed. Signing is only required for use on the device, development under the JDE can occur without signing the CODs.

OAEPUnformatterEngine

public OAEPUnformatterEngine(PrivateKeyDecryptorEngine engine,
                             Digest digest)

Creates an OAEPUnformatterEngine object based upon the given decryptor engine and digest algorithm.

Parameters:

engine - The PrivateKeyDecryptorEngine object used to decrypt the formatted message.

digest - The digest to be used during the unformatting process.

Since:

JDE 3.6.0

Category:

Signed: This element is only accessible by signed clients. If you intend to use this element, please contact RIM to establish the necessary agreements that will allow you to have your COD files signed. Signing is only required for use on the device, development under the JDE can occur without signing the CODs.

OAEPUnformatterEngine

public OAEPUnformatterEngine(PrivateKeyDecryptorEngine engine,
                             Digest digest,
                             byte[] parameters)

Creates an OAEPUnformatterEngine object based upon the given decryptor engine, digest algorithm and parameters.

Parameters:

engine - The PrivateKeyDecryptorEngine object used to decrypt the formatted message.

digest - The digest to be used during the unformatting process.

parameters - A byte array containing teh paramters to be compared to those found in the formatted message.

Since:

JDE 3.6.0

Category:

Signed: This element is only accessible by signed clients. If you intend to use this element, please contact RIM to establish the necessary agreements that will allow you to have your COD files signed. Signing is only required for use on the device, development under the JDE can occur without signing the CODs.

Method Detail

getAlgorithm

public String getAlgorithm()

Returns the name of the algorithm used, ie PublicKeyEncryptorEngine.getAlgorithm() + "_OAEP".

Since:

JDE 3.6.0

Category:

Signed: This element is only accessible by signed clients. If you intend to use this element, please contact RIM to establish the necessary agreements that will allow you to have your COD files signed. Signing is only required for use on the device, development under the JDE can occur without signing the CODs.

getInputBlockLength

public int getInputBlockLength()

Description copied from interface: BlockUnformatterEngine

Returns the length of an input block in bytes.

Since:

JDE 3.6.0

Category:

Signed: This element is only accessible by signed clients. If you intend to use this element, please contact RIM to establish the necessary agreements that will allow you to have your COD files signed. Signing is only required for use on the device, development under the JDE can occur without signing the CODs.

getOutputBlockLength

public int getOutputBlockLength()

Description copied from interface: BlockUnformatterEngine

Returns the length of an output block in bytes.

Since:

JDE 3.6.0

Category:

Signed: This element is only accessible by signed clients. If you intend to use this element, please contact RIM to establish the necessary agreements that will allow you to have your COD files signed. Signing is only required for use on the device, development under the JDE can occur without signing the CODs.

decryptAndUnformat

public int decryptAndUnformat(byte[] input,
                              int inputOffset,
                              byte[] output,
                              int outputOffset,
                              boolean lastBlock)
                       throws DecodeException,
                              BadPaddingException,
                              CryptoTokenException

Description copied from interface: BlockUnformatterEngine

Decrypts the input and then "unformats" it into the original plaintext.

Since:

JDE 3.6.0

Category:

Signed: This element is only accessible by signed clients. If you intend to use this element, please contact RIM to establish the necessary agreements that will allow you to have your COD files signed. Signing is only required for use on the device, development under the JDE can occur without signing the CODs.

decryptAndUnformat

public int decryptAndUnformat(byte[] input,
                              int inputOffset,
                              byte[] output,
                              int outputOffset)
                       throws DecodeException,
                              BadPaddingException,
                              CryptoTokenException

Description copied from interface: BlockUnformatterEngine

Decrypts the input and then "unformats" it into the original plaintext assuming this block is not the last block in the stream.

Since:

JDE 3.6.0

Category:

Signed: This element is only accessible by signed clients. If you intend to use this element, please contact RIM to establish the necessary agreements that will allow you to have your COD files signed. Signing is only required for use on the device, development under the JDE can occur without signing the CODs.