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

java.lang.Object
- iaik.pkcs.pkcs8.PrivateKeyInfo

All Implemented Interfaces:

ASN1Type, java.io.Serializable, java.security.Key, java.security.PrivateKey, javax.security.auth.Destroyable

Direct Known Subclasses:

DHPrivateKey, DSAPrivateKey, ECDSAPrivateKey, EcPrivateKey, ESDHPrivateKey, RSAPrivateKey, WrappedPrivateKey
```
public abstract class PrivateKeyInfo
extends java.lang.Object
implements java.io.Serializable, ASN1Type, java.security.PrivateKey
```
This class implements the Public-Key Cryptography Standards (PKCS) #8: Private-Key Information Syntax Specification Version 1.2 (RFC 5208) for storing private keys.
A Private-key information according to PKCS#8 combines a private key (of a public-key algorithm) and some attributes, which are used for developing trust in information like public keys from top-level certification authorities (see http://www.imc.org/rfc5208). PKCS#8 defines PrivateKeyInfo as an ASN.1 SEQUENCE containing the following components:
```
 PrivateKeyInfo ::= SEQUENCE {
   version Version,
   privateKeyAlgorithm PrivateKeyAlgorithmIdentifier,
   privateKey PrivateKey
   attributes [0] IMPLICIT Attributes OPTIONAL }
 
```
where:
```
 Version ::= INTEGER   -- Syntax Version Number
 PrivateKeyAlgorithmIdentifier ::= AlgorithmIdentifier  -- private key algorithm, e.g. rsaEncryption from PKCS#1
 PrivateKey ::= OCTET STRING   -- the value of the private key, e.g. a BER encoded RSAPrivateKey value
 Attributes ::= SET OF Attribute  -- additional information, encrypted together with the private-key information
 
```
This class may be extended for every particular private key implemetation wishing to support PKCS#8 PrivateKeyInfo.
This class provides a variety of methods for creating, parsing, de- and encoding private key informations.
See Also:

DHPrivateKey, DSAPrivateKey, RSAPrivateKey, Serialized Form

Field Summary

Fields
Modifier and Type Field and Description

protected AlgorithmID private_key_algorithm
Identifies the appertaining private-key algorithm.

protected ASN1 private_key_info
- Fields inherited from interface java.security.PrivateKey
  serialVersionUID

Fields
Modifier and Type	Field and Description
`protected AlgorithmID`	`private_key_algorithm` Identifies the appertaining private-key algorithm.
`protected ASN1`	`private_key_info`

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`PrivateKeyInfo()` Default Constructor for derived classes.
	`PrivateKeyInfo(ASN1Object obj)` Creates a new PrivateKeyInfo from an ASN1Object.
	`PrivateKeyInfo(byte[] arr)` Creates a new PrivateKeyInfo from a byte array.
	`PrivateKeyInfo(java.io.InputStream is)` Creates a new PrivateKeyInfo from an InputStream.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`protected void`	`createPrivateKeyInfo()` Creates a PrivateKeyInfo ASN.1 data structure (PKCS#8).
`void`	`decode(ASN1Object obj)` Decodes the given ASN.1 `PrivateKeyInfo` object for parsing the internal structure.
`protected abstract void`	`decode(byte[] privateKey)` Abstract method to be implemented for decoding a DER encoded private key.
`protected abstract byte[]`	`encode()` Abstract method to be implemented for encoding this private key according to DER.
`boolean`	`equals(java.lang.Object obj)` Compares this private key to another private key.
`abstract java.lang.String`	`getAlgorithm()` Returns the name of the algorithm.
`byte[]`	`getEncoded()` Returns this PrivateKeyInfo as a DER encoded ASN.1 data structure.
`java.lang.String`	`getFormat()` Returns the name of the encoding format..
`static java.security.PrivateKey`	`getPrivateKey(ASN1Object privateKeyInfo)` Creates a PrivateKeyInfo from an ASN1Object.
`static java.security.PrivateKey`	`getPrivateKey(byte[] privateKeyInfo)` Creates a PrivateKey from a DER encoded byte array in PKCS#8 PrivateKeyInfo format.
`ASN1Object`	`toASN1Object()` Returns this PrivateKeyInfo as ASN1Object.
`java.lang.String`	`toString()` Returns a string that represents the contents of this private key.
`void`	`writeTo(java.io.OutputStream os)` Writes this private key to an output stream.

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

Methods inherited from interface javax.security.auth.Destroyable
destroy, isDestroyed

- Field Detail
  - private_key_info
```
protected ASN1 private_key_info
```
  - private_key_algorithm
```
protected AlgorithmID private_key_algorithm
```
    Identifies the appertaining private-key algorithm.
- Constructor Detail
  - PrivateKeyInfo
```
protected PrivateKeyInfo()
```
    Default Constructor for derived classes.
  - PrivateKeyInfo
```
public PrivateKeyInfo(ASN1Object obj)
               throws java.security.InvalidKeyException
```
    Creates a new PrivateKeyInfo from an ASN1Object.
    This constructor may be used for parsing an already existing PrivateKeyInfo object, supplied as ASN1Object that may have been created by calling toASN1Object.
    
    Parameters:
    
    obj - the PrivateKeyInfo as ASN1Object
    
    Throws:
    
    java.security.InvalidKeyException - if the data can not be parsed
  - PrivateKeyInfo
```
public PrivateKeyInfo(java.io.InputStream is)
               throws java.security.InvalidKeyException,
                      java.io.IOException
```
    Creates a new PrivateKeyInfo from an InputStream.
    This constructor reads a PrivateKeyInfo previously written with method writeTo. This constructor cannot be used to read a serialized object.
    
    Parameters:
    
    is - the input stream from where the PrivateKeyInfo shall be read
    
    Throws:
    
    java.security.InvalidKeyException - if the data can not be parsed
    
    java.io.IOException - if an I/O error occurs
  - PrivateKeyInfo
```
public PrivateKeyInfo(byte[] arr)
               throws java.security.InvalidKeyException
```
    Creates a new PrivateKeyInfo from a byte array.
    This constructor may be used for parsing an already existing PrivateKeyInfo object, supplied as DER encoded ASN.1 structure, which may have been created by calling the getEncoded method of this class.
    
    Parameters:
    
    arr - the array containing the encoded PrivateKeyInfo
    
    Throws:
    
    java.security.InvalidKeyException - if the data can not be parsed
- Method Detail
  - decode
```
protected abstract void decode(byte[] privateKey)
                        throws java.security.InvalidKeyException
```
    Abstract method to be implemented for decoding a DER encoded private key.
    
    Parameters:
    
    privateKey - the private key as DER encoded byte array
    
    Throws:
    
    java.security.InvalidKeyException - if the does not match to the implemented public-key algorithm
  - encode
```
protected abstract byte[] encode()
```
    Abstract method to be implemented for encoding this private key according to DER.
    
    Returns:
    
    the private key as a DER encoded ASN.1 data structure
  - getAlgorithm
```
public abstract java.lang.String getAlgorithm()
```
    Returns the name of the algorithm.
    
    Specified by:
    
    getAlgorithm in interface java.security.Key
    
    Returns:
    
    the name of the algorithm
  - decode
```
public void decode(ASN1Object obj)
            throws CodingException
```
    Decodes the given ASN.1 PrivateKeyInfo object for parsing the internal structure.
    This method implements the ASN1Type interface and internally is called when creating a PKCS#8 PrivateKeyInfo object from an already existing PrivateKeyInfo object, supplied as ASN1Object or DER encoded ASN1Object.
    
    Specified by:
    
    decode in interface ASN1Type
    
    Parameters:
    
    obj - the PrivateKeyInfo as ASN1Object
    
    Throws:
    
    CodingException - if the ASN1Object could not be parsed
  - createPrivateKeyInfo
```
protected void createPrivateKeyInfo()
```
    Creates a PrivateKeyInfo ASN.1 data structure (PKCS#8).
    This method is called by extending classes for creating a PrivateKeyInfo. This method creates a PrivateKeyInfo as an ASN.1 SEQUENCE object with components as specified in the Public-Key Cryptography Standards (PKCS) #8: Private-Key Information Syntax Specification Version 1.2 (RFC 5208):
    - Version (integer)
    - PrivateKeyAlgorithmIdentifier
    - PrivateKey (OCTET STRING)
    - Attributes (SET Of Attribute; optional)
  - getPrivateKey
```
public static java.security.PrivateKey getPrivateKey(ASN1Object privateKeyInfo)
                                              throws java.security.InvalidKeyException
```
    Creates a PrivateKeyInfo from an ASN1Object.
    This is a static method and therefore may be called for creating a PrivateKeyInfo from the given ASN1Object without explicitly instantiating this class, e.g:
```
 PrivateKeyInfo priv_ki = PrivateKeyInfo.getPrivateKeyInfo(asn1_obj);
 
```
    The given ASN1Object represents an already existing PrivateKeyInfo object, and may have been created by calling toASN1Object.
    This method uses a KeyFactory for the registered algorithm to create the PrivateKeyInfo from the DER encoding of the supplied ASN1Object.
    Parameters:
    
    privateKeyInfo - the PrivateKeyInfo as ASN1Object
    
    Returns:
    
    a RSAPrivateKey, DSAPrivateKey or DHPrivateKey, depending on the AgorithmID inherent to the given ASN1Object
    
    Throws:
    
    java.security.InvalidKeyException - if the ASN1Object cannot be parsed or the inherent AlgorithmID does not match to any implemented private-key algorithm
  - getPrivateKey
```
public static java.security.PrivateKey getPrivateKey(byte[] privateKeyInfo)
                                              throws java.security.InvalidKeyException
```
    Creates a PrivateKey from a DER encoded byte array in PKCS#8 PrivateKeyInfo format. This is a static method and therefore may be called for creating a PrivateKey from the given DER encoded ASN1Object without explicitly instantiating this class, e.g:
```
 PrivateKey priv_ki = PrivateKeyInfo.getPrivateKey(key_array);
 
```
    This method uses a KeyFactory for the registered algorithm to create the PrivateKey from the supplied DER encoded byte array.
    Parameters:
    
    privateKeyInfo - the PrivateKey as DER encoded byte array
    
    Returns:
    
    a RSAPrivateKey, DSAPrivateKey or DHPrivateKey, depending on the AgorithmID inherent to the given privateKeyInfo
    
    Throws:
    
    java.security.InvalidKeyException - if the privateKey cannot be parsed
  - toASN1Object
```
public ASN1Object toASN1Object()
```
    Returns this PrivateKeyInfo as ASN1Object.
    
    Specified by:
    
    toASN1Object in interface ASN1Type
    
    Returns:
    
    this PrivateKeyInfo as ASN1Object
  - equals
```
public boolean equals(java.lang.Object obj)
```
    Compares this private key to another private key. This method simply compares der DER encoded version of the keys.
    
    Overrides:
    
    equals in class java.lang.Object
    
    Returns:
    
    true, if the 2 private keys are equal, false otherwise
  - getEncoded
```
public byte[] getEncoded()
```
    Returns this PrivateKeyInfo as a DER encoded ASN.1 data structure.
    
    Specified by:
    
    getEncoded in interface java.security.Key
    
    Returns:
    
    this PrivateKeyInfo as DER encoded byte array
  - getFormat
```
public java.lang.String getFormat()
```
    Returns the name of the encoding format..
    
    Specified by:
    
    getFormat in interface java.security.Key
    
    Returns:
    
    the string "PKCS#8"
  - writeTo
```
public void writeTo(java.io.OutputStream os)
             throws java.io.IOException
```
    Writes this private key to an output stream.
    
    Parameters:
    
    os - the output stream
    
    Throws:
    
    java.io.IOException - if an I/O error occurs
  - toString
```
public java.lang.String toString()
```
    Returns a string that represents the contents of this private key.
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    
    the string representation

Class PrivateKeyInfo

Field Summary

Fields inherited from interface java.security.PrivateKey

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface javax.security.auth.Destroyable

Field Detail

private_key_info

private_key_algorithm

Constructor Detail

PrivateKeyInfo

PrivateKeyInfo

PrivateKeyInfo

PrivateKeyInfo

Method Detail

decode

encode

getAlgorithm

decode

createPrivateKeyInfo

getPrivateKey

getPrivateKey

toASN1Object

equals

getEncoded

getFormat

writeTo

toString