EnvelopedDataStream ("Entrust Authority Security Toolkit for the Java Platform")

java.lang.Object
- iaik.pkcs.pkcs7.EnvelopedDataStream

All Implemented Interfaces:

ContentStream

Direct Known Subclasses:

SMimeEncrypted
```
public class EnvelopedDataStream
extends java.lang.Object
implements ContentStream
```
This class represents the stream-supporting implementation of the PKCS#7 content type EnvelopedData.
Each PKCS#7 content type is associated with a specific object identifier, derived from:
```
 pkcs-7 OBJECT IDENTIFIER ::=
   { iso(1) member-body(2) US(840) rsadsi(113549)
       pkcs(1) 7 }
 
```
The object identifier for the EnvelopedData content type is defined as:
envelopedData OBJECT IDENTIFIER ::= { pkcs-7 3 }
which corresponds to the OID string "1.2.840.1.113549.1.7.3".
The PKCS #7: Cryptographic Message Syntax Version 1.5 (RFC 2315) specifies the EnvelopedData content type for providing a syntax for building digital envelopes. Content of any type may be enveloped for any number of recipients in parallel. For each recipient, a commonly at random generated content-encryption key is encrypted with the particular recipient´s public key and - together with recipient-specific information - collected into a RecipientInfo value. The content is encrypted with the content-encryption key giving a EncryptedContent value, which - in combination with a recipient-specific encrypted content-encryption key - forms the digital envelope for each particular recipient. All RecipientInfo values are collected together with the encrypted content into anEnvelopedData value to be sent to each intended recipient.
This class implements the EnvelopedData structure resulting from the last step described above. The EnvelopedData type is defined as ASN.1 SEQUENCE type containing the following components (see PKCS #7: Cryptographic Message Syntax Version 1.5 (RFC 2315)):
```
 EnvelopedData ::= SEQUENCE {
   version                Version,
   recipientInfos         RecipientInfos,
   encryptedContentInfo   EncryptedContentInfo }
 

 RecipientInfos ::= SET OF RecipientInfo
 

 EncryptedContentInfo ::= SEQUENCE {
   contentType                 ContentType,
   contentEncryptionAlgorithm  ContentEncryptionAlgorithmIdentifier,
   encryptedContent            [0] IMPLICIT EncryptedContent OPTIONAL }
 

 EncryptedContent ::= OCTET STRING
 
```
The recipientInfos field is a non-empty collection of per-recipient information. The encryptedContentInfo field specifies the type of the content being enveloped, the content-encryption algorithm (the same for all recipients) used for encrypting the content, and the result of the content encryption. If the encrypted content value is not present in the encryptedContent field, it has to be supplied by other means.
A recipient, when receiving the EnvelopedData message, decrypts the corresponding encrypted content-encryption key with his/her private key for subsequently decrypting the encrypted content using the content-encryption key just recovered. The recipient's private key is referenced by an issuer distinguished name and an issuer-specific serial number that uniquely identify the certificate for the corresponding public key.
For more information consult the RSA PKCS #7: Cryptographic Message Syntax Version 1.5 (RFC 2315) specification.

When creating a new EnvelopedDataStream object for the data to be enveloped the symmetric algorithm has to be specified to be used for content-encryption. After setting the recipients, the EnvelopedDataStream object may be encoded and written to an output stream by using a proper writeTo method, e.g.:
1. Create a new EnvelopedDataStream object and specify the content encryption algorithm to be used by means of the EnvelopedDataStream(InputStream is, AlgorithmID contentEA) constructor:
```
     //the data to be enveloped supplied from an input stream:
     InputStream dataStream = ...;
     //use TripleDES in CBC mode for encrypting the content
     EnvelopedDataStream enveloped_data = new EnvelopedDataStream(dataStream, AlgorithmID.des_EDE3_CBC);
     
```
2. For each intended recipient, create a RecipientInfo object, and add all RecipientInfos to the EnvelopedDataStream structure by calling the setRecipientInfos method, e.g. (assuming to add two recipients with corresponding certificates cert1 and cert2; currently only the PKCS#1 rsaEncryption is supported as key- encryption algorithm):
```
     RecipientInfo[] recipients = new RecipientInfo[2];
     recipients[0] = new RecipientInfo(cert1, AlgorithmID.rsaEncryption);
     recipients[1] = new RecipientInfo(cert2, AlgorithmID.rsaEncryption);
     enveloped_data.setRecipientInfos(recipients);
     
```
3. Use a proper writeTo method for BER encoding the EnvelopedData object and writing it to an output stream. You optionally may specify a particular block size for splitting the encoding of encrypted content. This step also will perform the encryption of the symmetric content-encryption key for each participated recipient.
```
     int blockSize = ...;
     OutputStream encoded_stream = ...;
     enveloped_data.writeTo(encoded_stream, blockSize);
     
```
  respectively
```
     enveloped_data.writeTo(encoded_stream);
     
```
  It is recommended only to use the writeTo method where a particular block size can be specified, because it is the intended purpose of this stream-supporting EnvelopedData implementation to handle large amounts of data. When no block size is specified whole the encrypted content is encoded as primitive definite octet string, which advantageously may be done when using the non-stream supporting EnvelopedData implementation. When a positve block size is specified for encoding the EnvelopedData to a stream, the encrypted content is BER encoded as indefinite constructed octet string being composed of a series of definite primitive encoded octet strings of blockSize length:
```
     0x24 0x80
               0x04 <blocksize> <first encrypted content block>
               0x04 <blocksize> <second encrypted content block>
               0x04 <blocksize> <third encrypted content block>
                   ...
     0x00 0x00
     
```
  instead of:
```
     0x04 <length> <encrypted content>
     
```
  The indefinte constrcuted encoding scheme also may be preferable when intending to be compatible to the encoding practice of some particular application (for instance some versions of Netscape Navigator).
A recipient, when receiving a EnvelopedDataStream encoding, uses the EnvelopedDataStream(InputStream is) constructor for parsing the internal structure. Before reading the recovered content by means of the getInputStream method, the cipher has to be initialized for decryption with the particular recipient´s private key by calling the setupCipher method:
1. Create an EnvelopedDataStream structure from the supplied encoding, decode and parse the internal structure:
```
     EnvelopedDataStream enveloped_data = new EnvelopedDataStream(encoded_stream);
     
```
2. Get information about the inherent EncryptedContentInfo:
```
     EncryptedContentInfoStream eci = (EncryptedContentInfoStream)enveloped_data.getEncryptedContentInfo();
     System.out.println("Content type: "+eci.getContentType().getName());
     System.out.println("Content encryption algorithm: "+eci.getContentEncryptionAlgorithm().getName());
     
```
3. Get information about the included RecipientInfos:
```
     RecipientInfo[] recipients = enveloped_data.getRecipientInfos();
     System.out.pritnln("Included RecipientInfos:");
     for (int i=0; i < recipients.length; i++) {
        System.out.print("Recipient "+(i+1)+":");
        System.out.println(recipients[i].getIssuerAndSerialNumber());
     }
     
```
4. Use some recipient´s specific private key to decrypt the inherent encrypted secret key to be used for initializing the cipher for encrypted-content decryption:
```
     //setup cipher for recipient 1:
     int recipientInfoIndex = 0;
     enveloped_data.setupCipher(privateKey, recipientInfoIndex);
     
```
  Unlike the non-stream supporting EnvelopedData class where the encrypted-content decryption already is performed inside the setupCipher method, the cipher will be only initialized for decryption in this class. The encrypted-content decryption actually is done during reading the data obtained by calling the getInputStream method. So don´t call getInputStream before setting up the cipher!
5. Get and read the recovered content:
```
     InputStream data_is = enveloped_data.getInputStream();
     byte[] buf = new byte[1024];
     int r;
     while ((r = data_is.read(buf)) > 0) {
        // do something useful
     }
     
```
See Also:
RecipientInfo, EncryptedContentInfoStream

Field Summary

Fields
Modifier and Type	Field and Description
`protected int`	`block_size` The block size for block oriented stream encoding.
`protected EncryptedContentInfoStream`	`encrypted_content_info` The EncryptedContentInfo for the encrypted content.
`protected java.util.Vector`	`recipient_infos` Repository for the RecipientInfos.
`protected javax.crypto.SecretKey`	`symmetric_key` The secret content encryption key.
`protected int`	`version` The version number; currently 0.

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`EnvelopedDataStream()` Default constructor for dynamic object creation in ContentInfo.
	`EnvelopedDataStream(java.io.InputStream is)` Creates a new EnvelopedDataStream where the DER encoded data is read from the given InputStream.
	`EnvelopedDataStream(java.io.InputStream is, AlgorithmID contentEA)` Creates a new PKCS#7 EnvelopedDataStream object where the content to be enveloped is read from the supplied InputStream.
	`EnvelopedDataStream(java.io.InputStream is, AlgorithmID contentEA, int keyLength)` Creates a new PKCS#7 EnvelopedDataStream object where the content to be enveloped is read from the supplied InputStream.
	`EnvelopedDataStream(RecipientInfo[] recipients, EncryptedContentInfoStream encryptedCI)` Constructs an EnvelopedDataStream object with an already created EncryptedContentInfoStream.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`addRecipientInfo(RecipientInfo recipient)` Adds one recipient to the list of recipient infos.
`void`	`decode(java.io.InputStream is)` Reads and decodes the EnvelopedData from a DerInputStream.
`ObjectID`	`getContentType()` Returns the content type this class implements.
`java.lang.Object`	`getEncryptedContentInfo()` Returns the encrypted content info included in this `EnvelopedDataStream` object.
`java.io.InputStream`	`getInputStream()` Returns an InputStream from where the decrypted data can be read.
`RecipientInfo`	`getRecipientInfo(java.security.cert.X509Certificate recipientCertificate)` Returns the recipient info matching to the supplied recipient certificate.
`RecipientInfo[]`	`getRecipientInfos()` Returns all the recipient infos included in this `EnvelopedData` object.
`int`	`getVersion()` Returns the syntax version number.
`void`	`setBlockSize(int blockSize)` Sets the block size for defining the length of each definite primitive encoded octet string component.
`void`	`setRecipientInfos(RecipientInfo[] recipients)` Sets the recipient infos.
`void`	`setupCipher(java.security.Key key)` Uses the given symmetric key to setup the cipher for decrypting the content.
`void`	`setupCipher(java.security.PrivateKey recipientPrivateKey, int recipientInfoIndex)` Uses the specified private key to setup the Cipher for decrypting the content-encryption key and subsequently using it to decrypt the encrypted content of this`EnvelopedDataStream` object for the requesting recipient, specified by its `recipientInfoIndex`.
`ASN1Object`	`toASN1Object()` Returns this EnvelopedDataStream as ASN1Object.
`protected ASN1Object`	`toASN1Object(int blockSize)` Returns this EnvelopedData as ASN1Object.
`java.lang.String`	`toString()` Returns a string giving some information about this `EnvelopedData` object.
`java.lang.String`	`toString(boolean detailed)` Returns a string giving some - if requested - detailed information about this `EnvelopedData` object.
`void`	`writeTo(java.io.OutputStream os)` DER encoded this EnvelopedData and writes the encoding to the supplied output stream.
`void`	`writeTo(java.io.OutputStream os, int blockSize)` Writes the BER encoding of this EnvelopedData to the supplied output stream where a constructed OCTET STRING is used for encoding the content.

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

- Field Detail
  - version
```
protected int version
```
    The version number; currently 0.
  - recipient_infos
```
protected java.util.Vector recipient_infos
```
    Repository for the RecipientInfos.
  - encrypted_content_info
```
protected EncryptedContentInfoStream encrypted_content_info
```
    The EncryptedContentInfo for the encrypted content.
  - symmetric_key
```
protected javax.crypto.SecretKey symmetric_key
```
    The secret content encryption key.
  - block_size
```
protected int block_size
```
    The block size for block oriented stream encoding.
- Constructor Detail
  - EnvelopedDataStream
```
protected EnvelopedDataStream()
```
    Default constructor for dynamic object creation in ContentInfo.
  - EnvelopedDataStream
```
public EnvelopedDataStream(java.io.InputStream is,
                   AlgorithmID contentEA)
                    throws java.security.NoSuchAlgorithmException
```
    Creates a new PKCS#7 EnvelopedDataStream object where the content to be enveloped is read from the supplied InputStream. The content type is set to PKCS#7 Data.
    When using this constructor, automatically a symmetric key for content encryption is generated. For that reason this constructor shall not be used in situations where the desired content encryption algorithm requires a specific key/parameter handling. In such cases the EnvelopedDataStream(RecipientInfo[], EncryptedContentInfoStream) constructor shall be used to be supplied with precomputed RecipientInfos and EncryptedContentInfo. Consult the EncryptedContentInfoStream class documentation for more information about special key/parameter handling.
    
    Parameters:
    is - the InputStream containing the data to envelope
    contentEA - the content encryption algorithm for encrypting the content
    
    Throws:
    
    java.security.NoSuchAlgorithmException - if there is no implementation for the specified algorithm
  - EnvelopedDataStream
```
public EnvelopedDataStream(java.io.InputStream is,
                   AlgorithmID contentEA,
                   int keyLength)
                    throws java.security.NoSuchAlgorithmException
```
    Creates a new PKCS#7 EnvelopedDataStream object where the content to be enveloped is read from the supplied InputStream. The content type is set to PKCS#7 Data.
    When using this constructor, automatically a symmetric key for content encryption is generated. If the specified content encryption algorithm supports variable key lengths, a particular key length may be set by means of the keyLength parameter. If no length is specified, the defined default key length will be used. If the algorithm only works with keys of fixed-size length, the keyLength parameter may be set to -1 or the EnvelopedDataStream(InputStream is, AlgorithmID contentEA) constructor may be used.
    This constructor shall not be used in situations where the desired content encryption algorithm requires a specific parameter handling. In such cases the EnvelopedDataStream(RecipientInfo[], EncryptedContentInfoStream) constructor shall be used to be supplied with precomputed RcipientInfos and EncryptedContentInfo. Consult the EncryptedContentInfoStream class documentation for more information about special key/parameter handling.
    
    Parameters:
    is - the InputStream containing the data to envelope
    contentEA - the content encryption algorithm for encrypting the content
    keyLength - the key length that may be set when using a content encryption algorithm that supports variable key lengths
    
    Throws:
    
    java.security.NoSuchAlgorithmException - if there is no implementation for the specified algorithm
  - EnvelopedDataStream
```
public EnvelopedDataStream(RecipientInfo[] recipients,
                   EncryptedContentInfoStream encryptedCI)
```
    Constructs an EnvelopedDataStream object with an already created EncryptedContentInfoStream. The given array of RecipientInfo specifies a collection of per-recipient information, and the given EncryptedContentInfoStream supplies the already encrypted content.
    
    Parameters:
    recipients - information about the recipients
    encryptedCI - the encrypted content info
  - EnvelopedDataStream
```
public EnvelopedDataStream(java.io.InputStream is)
                    throws PKCSParsingException,
                           java.io.IOException
```
    Creates a new EnvelopedDataStream where the DER encoded data is read from the given InputStream.
    
    Parameters:
    is - the InputStream holding a DER encoded PKCS#7 EnvelopedData object
    
    Throws:
    
    java.io.IOException - if an I/O error occurs during reading from the InputStream
    
    PKCSParsingException - if an error occurs while parsing the object
- Method Detail
  - decode
```
public void decode(java.io.InputStream is)
            throws java.io.IOException,
                   PKCSParsingException
```
    Reads and decodes the EnvelopedData from a DerInputStream. If the supplied InputStream actually is not an instance of DerInputStream, internally a DerInputStream is created before parsing the data.
    
    Specified by:
    
    decode in interface ContentStream
    
    Parameters:
    is - the InputStream holding a DER encoded PKCS#7 EnvelopedData object
    
    Throws:
    
    java.io.IOException - if an I/O error occurs during reading from the InputStream
    
    PKCSParsingException - if an error occurs while parsing the object
  - getContentType
```
public ObjectID getContentType()
```
    Returns the content type this class implements.
    
    Specified by:
    
    getContentType in interface ContentStream
    
    Returns:
    ObjectID.pkcs7_envelopedData
  - setRecipientInfos
```
public void setRecipientInfos(RecipientInfo[] recipients)
```
    Sets the recipient infos. Each single RecipientInfo specifies the particular recipient´s certificate by IssuerAndAserialNumber, and the key encryption algorithm to be used; currently only PKCS#1 rsaEncryption is supported.
    Example:
```
 RecipientInfo[] recipients = new RecipientInfo[2];
 recipients[0] = new RecipientInfo(cert1, AlgorithmID.rsaEncryption);
 recipients[1] = new RecipientInfo(cert2, AlgorithmID.rsaEncryption);
 enveloped_data.setRecipientInfos(recipients);
 
```
    Parameters:
    recipients - a collection of per-recipient information
    See Also:
    RecipientInfo
  - addRecipientInfo
```
public void addRecipientInfo(RecipientInfo recipient)
```
    Adds one recipient to the list of recipient infos.
    The RecipientInfo specifies the particular recipient´s certificate by IssuerAndAserialNumber, and the key encryption algorithm to be used; currently only PKCS#1 rsaEncryption is supported.
    Example:
```
 RecipientInfo recipient = new RecipientInfo(cert, AlgorithmID.rsaEncryption);
 enveloped_data.addRecipientInfo(recipient);
 
```
    Parameters:
    recipient - the RecipientInfo to be added
  - setBlockSize
```
public void setBlockSize(int blockSize)
```
    Sets the block size for defining the length of each definite primitive encoded octet string component. If the value of blockSize is smaller or equal to zero the whole encrypted data is encoded as definite primitive octet string. This method may be used for enforcing block encoding when wrapping the EnvelopedData into a ContentInfo.
    
    Specified by:
    
    setBlockSize in interface ContentStream
    
    Parameters:
    blockSize - for defining the encoding scheme and setting the octet string component length, if positive
    See Also:
    OCTET_STRING
  - setupCipher
```
public void setupCipher(java.security.PrivateKey recipientPrivateKey,
               int recipientInfoIndex)
                 throws PKCSException,
                        java.security.NoSuchAlgorithmException,
                        java.security.InvalidKeyException
```
    Uses the specified private key to setup the Cipher for decrypting the content-encryption key and subsequently using it to decrypt the encrypted content of thisEnvelopedDataStream object for the requesting recipient, specified by its recipientInfoIndex.
    This method first uses the given private key for decrypting the encrypted temporary symmetric key obtained from the corresponding RecipientInfo structure, and subsequently uses this key to initialize a CipherInputStream for the inherent encrypted content.
    Unlike the non-stream supporting EnvelopedData class where the encrypted-content decryption already is performed inside the setupCipher method, the cipher will be only initialized for decrypting in this class. The encrypted-content decryption actually is done during reading the data obtained by calling the getInputStream method. So don´t call getInputStream before setting up the cipher!
    Attention! This method only can be used when the content encryption AlgorithmID contains IV parameters encoded as an OCTET_STRING. When the algorithmID contains parameters of other type (e.g. S/MIME RC2-CBC parameters) they have to be decoded separatly, and the setupCipher(Key key, AlgorithmParameterSpec) method of the EncryptedContentInfoStream class has to be used to setup the cipher for content decryption, e.g.:
```
 //get the ECI from the enveloped data:
 EncryptedContentInfoStream eci =
      (EncryptedContentInfoStream)enveloped_data.getEncryptedContentInfo();
 // get the recipient infos
 RecipientInfo[] recipients = enveloped_data.getRecipientInfos();
 // use the specific recipient´s private key for decrypting the required
 // symmetric content encryption key, e.g.:
 SecretKey secretKey =
   recipient_infos[0].decryptKey(recipientPrivateKey)
 //get the content encryption algorithm:
 AlgorithmID contentEA = eci.getContentEncryptionAlgorithm();
 // get the parameters as SEQUENCE
 SEQUENCE seq = (SEQUENCE)contentEA.getParameter();
 // the iv is the second component
 OCTET_STRING oct = (OCTET_STRING)seq.getComponentAt(1);
 // create an IvParameterSpec:
 IvParameterSpec ivSpec = new IvParameterSpec(oct.getValue());
 //now setup the cipher with previously decrypted recipient key amd params
 eci.setupCipher(secretKey, ivSpec);
 //get and read the data thereby actually performing the decryption
 InputStream data_is = signed_data.getInputStream();
 byte[] buf = new byte[1024];
 int r;
 while ((r = data_is.read(buf)) > 0) {
   // do something useful
 }
 
```
    Parameters:
    recipientPrivateKey - the private key of the recipient to be used for decrypting the encrypted content-encryption key.
    recipientInfoIndex - specifies which RecipientInfo the private key belongs to
    
    Throws:
    
    PKCSException - if there occurs an error while decrypting the data
    
    java.security.NoSuchAlgorithmException - if there is no implementation of the content-encryption algorithm
    
    java.security.InvalidKeyException - if the specified private key is not valid
  - setupCipher
```
public void setupCipher(java.security.Key key)
                 throws PKCSException,
                        java.security.NoSuchAlgorithmException,
                        java.security.InvalidKeyException
```
    Uses the given symmetric key to setup the cipher for decrypting the content.
    Unlike the non-stream supporting EnvelopedData class where the encrypted-content decryption already is performed inside the setupCipher method, the cipher will be only initialized for decrypting in this class. The encrypted-content decryption actually is done during reading the data obtained by calling the getInputStream method. So don´t call getInputStream before setting up the cipher!
    Attention! This method only can be used when the content encryption AlgorithmID contains IV parameters encoded as an OCTET_STRING. When the algorithmID contains parameters of other type (e.g. S/MIME RC2-CBC parameters) they have to be decoded separatly, and the setupCipher(Key key, AlgorithmParameterSpec) method of the EncryptedContentInfoStream class has to be used to setup the cipher for content decryption, e.g.:
```
 //get the ECI from the enveloped data:
 EncryptedContentInfoStream eci =
      (EncryptedContentInfoStream)enveloped_data.getEncryptedContentInfo();
 //get the content encryption algorithm:
 AlgorithmID contentEA = eci.getContentEncryptionAlgorithm();
 // get the parameters as SEQUENCE
 SEQUENCE seq = (SEQUENCE)contentEA.getParameter();
 // the iv is the second component
 OCTET_STRING oct = (OCTET_STRING)seq.getComponentAt(1);
 // create an IvParameterSpec:
 IvParameterSpec ivSpec = new IvParameterSpec(oct.getValue());
 //now setup the cipher with previously decrypted recipient key amd params
 eci.setupCipher(secretKey, ivSpec);
 //get and read the data thereby actually performing the decryption
 InputStream data_is = signed_data.getInputStream();
 byte[] buf = new byte[1024];
 int r;
 while ((r = data_is.read(buf)) > 0) {
   // do something useful
 }
 
```
    Parameters:
    key - the temporary symmetric key that has been used to encrypt the content, and now is used for decrypting it again
    
    Throws:
    
    PKCSException - if there occurs an error while decrypting the data
    
    java.security.NoSuchAlgorithmException - if there is no implementation for the content-encryption algorithm
    
    java.security.InvalidKeyException - if the specified private key is not valid
  - getInputStream
```
public java.io.InputStream getInputStream()
```
    Returns an InputStream from where the decrypted data can be read. Attention! The stream only may be read once.
    When having created a new EnvelopedDataStream object to be encoded to a stream, this method should not be utilized at all, since the stream automatically will be read during performing the encoding (which is done when calling a writeTo method).
    When having decoded and parsed a received EnvelopedDataStream object comimg from some stream, this method may be used for obtaining the raw (decrypted) data after having setup the cipher.
    
    Returns:
    an InputStream for reading the decrypted data
  - getVersion
```
public int getVersion()
```
    Returns the syntax version number.
    
    Returns:
    the syntax version number
  - getRecipientInfos
```
public RecipientInfo[] getRecipientInfos()
```
    Returns all the recipient infos included in this EnvelopedData object.
    
    Returns:
    an array containing all the RecipientInfo objects included into this EnvelopedData
    See Also:
    EnvelopedData#setRecipientInfos
  - getRecipientInfo
```
public RecipientInfo getRecipientInfo(java.security.cert.X509Certificate recipientCertificate)
```
    Returns the recipient info matching to the supplied recipient certificate. This method may be used by a recipient for quering for the recipient info that holds the content encryption key encrypted with the public key of the given certificate.
    
    Returns:
    the recipient info matching to the supplied recipient certificate, or null if no recipient info belonging to the given certificate can be found
    See Also:
    EnvelopedData#setRecipientInfos
  - getEncryptedContentInfo
```
public java.lang.Object getEncryptedContentInfo()
```
    Returns the encrypted content info included in this EnvelopedDataStream object. When calling this method for obtaining the inherent EncryptedContentInfoStream an explicit cast to EncryptedContentInfoStream has to be made:
```
 EncryptedContentInfoStream eci = (EncryptedContentInfoStream)enveloped_data.getEncryptedContentInfo();
 
```
    Returns:
    the encrypted content info
  - toASN1Object
```
public ASN1Object toASN1Object()
                        throws PKCSException
```
    Returns this EnvelopedDataStream as ASN1Object.
    
    Specified by:
    
    toASN1Object in interface ContentStream
    
    Returns:
    this EnvelopedDataStream as ASN1Object.
    
    Throws:
    
    PKCSException - if the ASN1Object could not be created
  - toASN1Object
```
protected ASN1Object toASN1Object(int blockSize)
                           throws PKCSException
```
    Returns this EnvelopedData as ASN1Object.
    If is positive a constructed OCTET STRING is used for encoding the encrypted content. This method also will perform the encryption of the symmetric content-encryption key for each participated recipient.
    
    Parameters:
    blockSize - the block size defining the encoding scheme - and specifying the length of each primitive encoded octet string component, if positive
    
    Returns:
    this PKCS#7 EnvelopedData as ASN1Object
    
    Throws:
    
    PKCSException - if the ASN1Object could not be created
  - writeTo
```
public void writeTo(java.io.OutputStream os)
             throws java.io.IOException
```
    DER encoded this EnvelopedData and writes the encoding to the supplied output stream.
    
    Parameters:
    os - the output stream to which this EnvelopedData shall be written
    
    Throws:
    
    java.io.IOException
  - writeTo
```
public void writeTo(java.io.OutputStream os,
           int blockSize)
             throws java.io.IOException
```
    Writes the BER encoding of this EnvelopedData to the supplied output stream where a constructed OCTET STRING is used for encoding the content.
    When encoding the content data to the given stream it is piped through a cipher stream thereby performing the content encryption.
    If the a positive blockSize value is specified, the encrypted content is encoded as indefinite constructed octet string being composed of a certain number of definite primitive encoded octet strings of blockSize length:
```
 0x24 0x80
           0x04 <blocksize> <first encrypted content block>
           0x04 <blocksize> <second encrypted content block>
           0x04 <blocksize> <third encrypted content block>
                ...
 0x00 0x00
 
```
    Otherwise, whole the encrypted content is encoded as definite primitive octet string:
```
  0x04 <length> <encrypted content>
 
```
    Parameters:
    os - the output stream to which this SignedData shall be written
    blockSize - the block size defining the encoding scheme - and specifying the length of each primitive encoded octet string component, if positive
    
    Throws:
    
    java.io.IOException - if an error occurs during writing the object
  - toString
```
public java.lang.String toString()
```
    Returns a string giving some information about this EnvelopedData object.
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    the string representation
  - toString
```
public java.lang.String toString(boolean detailed)
```
    Returns a string giving some - if requested - detailed information about this EnvelopedData object.
    
    Specified by:
    
    toString in interface ContentStream
    
    Parameters:
    detailed - - whether or not to give detailed information
    
    Returns:
    the string representation

Class EnvelopedDataStream

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

version

recipient_infos

encrypted_content_info

symmetric_key

block_size

Constructor Detail

EnvelopedDataStream

EnvelopedDataStream

EnvelopedDataStream

EnvelopedDataStream

EnvelopedDataStream

Method Detail

decode

getContentType

setRecipientInfos

addRecipientInfo

setBlockSize

setupCipher

setupCipher

getInputStream

getVersion

getRecipientInfos

getRecipientInfo

getEncryptedContentInfo

toASN1Object

toASN1Object

writeTo

writeTo

toString

toString