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KeyTransRecipientInformation.javaAPI DocBouncy Castle Crypto API 1.41 (Java 1.5)5434Wed Oct 01 10:55:28 BST 2008org.bouncycastle.cms

KeyTransRecipientInformation

public class KeyTransRecipientInformation extends RecipientInformation
the KeyTransRecipientInformation class for a recipient who has been sent a secret key encrypted using their public key that needs to be used to extract the message.

Fields Summary
private org.bouncycastle.asn1.cms.KeyTransRecipientInfo
_info
Constructors Summary
public KeyTransRecipientInformation(org.bouncycastle.asn1.cms.KeyTransRecipientInfo info, org.bouncycastle.asn1.x509.AlgorithmIdentifier encAlg, InputStream data)

        super(encAlg, AlgorithmIdentifier.getInstance(info.getKeyEncryptionAlgorithm()), data);
        
        this._info = info;
//        this._encAlg = encAlg;
        this._rid = new RecipientId();

        RecipientIdentifier r = info.getRecipientIdentifier();

        try
        {
            if (r.isTagged())
            {
                ASN1OctetString octs = ASN1OctetString.getInstance(r.getId());

                _rid.setSubjectKeyIdentifier(octs.getOctets());
            }
            else
            {
                IssuerAndSerialNumber   iAnds = IssuerAndSerialNumber.getInstance(r.getId());

                _rid.setIssuer(iAnds.getName().getEncoded());
                _rid.setSerialNumber(iAnds.getSerialNumber().getValue());
            }
        }
        catch (IOException e)
        {
            throw new IllegalArgumentException("invalid rid in KeyTransRecipientInformation");
        }
Methods Summary
public CMSTypedStreamgetContentStream(java.security.Key key, java.lang.String prov)
decrypt the content and return it as a byte array.

        return getContentStream(key, CMSUtils.getProvider(prov));
public CMSTypedStreamgetContentStream(java.security.Key key, java.security.Provider prov)

        byte[]  encryptedKey = _info.getEncryptedKey().getOctets();
        String  keyExchangeAlgorithm = getExchangeEncryptionAlgorithmName(_keyEncAlg.getObjectId());
        String  alg = CMSEnvelopedHelper.INSTANCE.getSymmetricCipherName(_encAlg.getObjectId().getId());

        try
        {
            Cipher  keyCipher = CMSEnvelopedHelper.INSTANCE.getSymmetricCipher(keyExchangeAlgorithm, prov);
            Key     sKey;
            
            try
            {
                keyCipher.init(Cipher.UNWRAP_MODE, key);

                sKey = keyCipher.unwrap(encryptedKey, alg, Cipher.SECRET_KEY);
            }
            catch (GeneralSecurityException e)   // some providers do not support UNWRAP
            {
                keyCipher.init(Cipher.DECRYPT_MODE, key);

                sKey = new SecretKeySpec(keyCipher.doFinal(encryptedKey), alg);
            }
            catch (IllegalStateException e)   // some providers do not support UNWRAP
            {
                keyCipher.init(Cipher.DECRYPT_MODE, key);

                sKey = new SecretKeySpec(keyCipher.doFinal(encryptedKey), alg);
            }
            catch (UnsupportedOperationException e)   // some providers do not support UNWRAP
            {
                keyCipher.init(Cipher.DECRYPT_MODE, key);

                sKey = new SecretKeySpec(keyCipher.doFinal(encryptedKey), alg);
            }
            catch (ProviderException e)   // some providers do not support UNWRAP
            {
                keyCipher.init(Cipher.DECRYPT_MODE, key);

                sKey = new SecretKeySpec(keyCipher.doFinal(encryptedKey), alg);
            }

            return getContentFromSessionKey(sKey, prov);
        }
        catch (NoSuchAlgorithmException e)
        {
            throw new CMSException("can't find algorithm.", e);
        }
        catch (InvalidKeyException e)
        {
            throw new CMSException("key invalid in message.", e);
        }
        catch (NoSuchPaddingException e)
        {
            throw new CMSException("required padding not supported.", e);
        }
        catch (IllegalBlockSizeException e)
        {
            throw new CMSException("illegal blocksize in message.", e);
        }
        catch (BadPaddingException e)
        {
            throw new CMSException("bad padding in message.", e);
        }
private java.lang.StringgetExchangeEncryptionAlgorithmName(org.bouncycastle.asn1.DERObjectIdentifier oid)

        if (PKCSObjectIdentifiers.rsaEncryption.equals(oid))
        {
            return "RSA/ECB/PKCS1Padding";
        }
        
        return oid.getId();