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net.rim.device.api.crypto.encoder
Class SignatureEncoder

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

public abstract class SignatureEncoder

extends Object

Defines encode signatures produced by the SignatureSigner classes. The details of creating and using the appropriate encoding algorithm are left to SignatureEncoder and are completely transparent to the developer.

Encoding Signatures

Encoding a signature simply involves calling the public static encode() method with a SignatureSigner object and a string that contains the requested encoding algorithm. For example, to encode an ECDSASignatureSigner using X509 encoding, code similar to the following would be used:

                    
      PrivateKey privateKey = ...; 
      SignatureSigner signer = new ECDSASignatureSigner( privateKey );
      String message = "Buy 10000 shares of Jabroni Jeans";
      signer.update( message );
      EncodedSignature encodedSignature = SignatureEncoder.encode( signer, "X509" );
 

where signer is a valid ECDSASignatureSigner object that has been created with the appropriate parameters.

Decoding Signatures

Decoding a signature involves calling the public static decode() method in this class with an EncodedSignature object and the public key to use for verification. Decoding an ECDSA signature using the X509 encoding algorithm can be accomplished by using code similar to the following:

      PublicKey publicKey = ...;
      byte[] encodedSignatureData = ...;
      SignatureDecoder decoder = SignatureDecoder.decode( encodedSignatureData, "X509" );
      SignatureVerifier verifier = decoder.getVerifier( publicKey );
 

Only the encoded signature and encoding algorithm into decode. The user gets back a SignatureDecoder object which they can then pass a public key into to create a signature verifier. The user can also call the initialize function of the decoder in order to change the digest used by the signature verifier.

Supported Encoding Algorithms

Please see here for a list of the RIM supplied encoding algorithms. Currently, RIM provides the following signature encoding algorithms, which can be accessed with the specifed string :

X509 encoding	use the encoding string "X509"
WTLS encoding	use the encoding string "WTLS"
CMS encoding	use the encoding string "CMS"

The X509 encoding is defined in RFC 2459. The WTLS encoding is found in WAP-199-WTLS from Feb 2000. Finally, the CMS encoding is defined in RFC 2630.

For algorithms not found in this list, a developer can implement additional signature encoding algorithms that can be integrated into the Crypto API.

See the tutorial on Adding Encoders.

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.

See Also:

EncodedSignature, SignatureDecoder, DecodedSignature

Constructor Summary

Method Summary

static EncodedSignature

encode(SignatureSigner signer, String encodingAlgorithm) Takes in the provided signature signer and returns an encoded signature using the specified encoding algorithm.

Methods inherited from class java.lang.Object

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

Constructor Detail

Method Detail

encode

public static EncodedSignature encode(SignatureSigner signer,
                                      String encodingAlgorithm)
                               throws NoSuchAlgorithmException,
                                      CryptoTokenException,
                                      CryptoUnsupportedOperationException

Takes in the provided signature signer and returns an encoded signature using the specified encoding algorithm.

Parameters:

signer - The signature signer to use for signing.

encodingAlgorithm - A String representing the encoding algorithm to use such as "X509".

Returns:

An encoded signature.

Throws:

NoSuchAlgorithmException - Thrown if the encoding algorithm cannot be found.

CryptoTokenException - Thrown if an error occurs with the crypto token or the crypto token is invalid.

CryptoUnsupportedOperationException - Thrown if a call is made to an unsupported operation.

Since:

JDE 3.6

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.