java.lang.Object
- net.i2p.data.DataStructureImpl
- - net.i2p.data.Certificate

All Implemented Interfaces:

Serializable, DataStructure

Direct Known Subclasses:

KeyCertificate
```
public class Certificate
extends DataStructureImpl
```
Defines a certificate that can be attached to various I2P structures, such as RouterIdentity and Destination, allowing routers and clients to help manage denial of service attacks and the network utilization. Certificates can even be defined to include identifiable information signed by some certificate authority, though that use probably isn't appropriate for an anonymous network ;) Todo: Properly support multiple certificates

Author:

jrandom

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type	Field	Description
`protected byte[]`	`_payload`
`protected int`	`_type`
`static int`	`CERTIFICATE_LENGTH_SIGNED_WITH_HASH`
`static int`	`CERTIFICATE_TYPE_HASHCASH`	specifies a Hashcash style certificate
`static int`	`CERTIFICATE_TYPE_HIDDEN`	we should not be used for anything (don't use us in the netDb, in tunnels, or tell others about us)
`static int`	`CERTIFICATE_TYPE_KEY`
`static int`	`CERTIFICATE_TYPE_MULTIPLE`	Contains multiple certs
`static int`	`CERTIFICATE_TYPE_NULL`	Specifies a null certificate type with no payload
`static int`	`CERTIFICATE_TYPE_SIGNED`	Signed with 40-byte Signature and (optional) 32-byte hash
`static Certificate`	`NULL_CERT`

Constructor Summary

Constructors
Constructor Description

Certificate()

Certificate(int type, byte[] payload)

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`static Certificate`	`create(byte[] data, int off)`	If null, P256 key, or Ed25519 key cert, return immutable static instance, else create new
`static Certificate`	`create(InputStream in)`	If null, P256 key, or Ed25519 key cert, return immutable static instance, else create new
`boolean`	`equals(Object object)`
`int`	`getCertificateType()`
`byte[]`	`getPayload()`
`int`	`hashCode()`
`int`	`readBytes(byte[] source, int offset)`
`void`	`readBytes(InputStream in)`	Load up the current object with data from the given stream.
`void`	`setCertificateType(int type)`
`void`	`setPayload(byte[] payload)`
`int`	`size()`
`KeyCertificate`	`toKeyCertificate()`	Up-convert this to a KeyCertificate
`String`	`toString()`
`int`	`writeBytes(byte[] target, int offset)`
`void`	`writeBytes(OutputStream out)`	Write out the data structure to the stream, using the format defined in the I2P data structure specification.

Methods inherited from class net.i2p.data.DataStructureImpl
calculateHash, fromBase64, fromByteArray, read, toBase64, toByteArray

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

- Field Detail
  - NULL_CERT
```
public static final Certificate NULL_CERT
```
  - _type
```
protected int _type
```
  - _payload
```
protected byte[] _payload
```
  - CERTIFICATE_TYPE_NULL
```
public static final int CERTIFICATE_TYPE_NULL
```
    Specifies a null certificate type with no payload
    
    See Also:
    
    Constant Field Values
  - CERTIFICATE_TYPE_HASHCASH
```
public static final int CERTIFICATE_TYPE_HASHCASH
```
    specifies a Hashcash style certificate
    
    See Also:
    
    Constant Field Values
  - CERTIFICATE_TYPE_HIDDEN
```
public static final int CERTIFICATE_TYPE_HIDDEN
```
    we should not be used for anything (don't use us in the netDb, in tunnels, or tell others about us)
    
    See Also:
    
    Constant Field Values
  - CERTIFICATE_TYPE_SIGNED
```
public static final int CERTIFICATE_TYPE_SIGNED
```
    Signed with 40-byte Signature and (optional) 32-byte hash
    
    See Also:
    
    Constant Field Values
  - CERTIFICATE_LENGTH_SIGNED_WITH_HASH
```
public static final int CERTIFICATE_LENGTH_SIGNED_WITH_HASH
```
  - CERTIFICATE_TYPE_MULTIPLE
```
public static final int CERTIFICATE_TYPE_MULTIPLE
```
    Contains multiple certs
    
    See Also:
    
    Constant Field Values
  - CERTIFICATE_TYPE_KEY
```
public static final int CERTIFICATE_TYPE_KEY
```
    Since:
    
    0.9.12
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - Certificate
```
public Certificate()
```
  - Certificate
```
public Certificate(int type,
                   byte[] payload)
```
    Throws:
    
    IllegalArgumentException - if type < 0
- Method Detail
  - create
```
public static Certificate create(byte[] data,
                                 int off)
                          throws DataFormatException
```
    If null, P256 key, or Ed25519 key cert, return immutable static instance, else create new
    
    Throws:
    
    DataFormatException - if not enough bytes
    
    Since:
    
    0.8.3
  - create
```
public static Certificate create(InputStream in)
                          throws DataFormatException,
                                 IOException
```
    If null, P256 key, or Ed25519 key cert, return immutable static instance, else create new
    
    Throws:
    
    DataFormatException
    
    IOException
    
    Since:
    
    0.8.3
  - getCertificateType
```
public int getCertificateType()
```
  - setCertificateType
```
public void setCertificateType(int type)
```
    Throws:
    
    IllegalArgumentException - if type < 0
    
    IllegalStateException - if already set
  - getPayload
```
public byte[] getPayload()
```
  - setPayload
```
public void setPayload(byte[] payload)
```
    Throws:
    
    IllegalStateException - if already set
  - readBytes
```
public void readBytes(InputStream in)
               throws DataFormatException,
                      IOException
```
    Description copied from interface: DataStructure
    
    Load up the current object with data from the given stream. Data loaded this way must match the I2P data structure specification. Warning - many classes will throw IllegalStateException if data is already set.
    
    Parameters:
    
    in - stream to read from
    
    Throws:
    
    IllegalStateException - if already set
    
    DataFormatException - if the data is improperly formatted
    
    IOException - if there was a problem reading the stream
  - writeBytes
```
public void writeBytes(OutputStream out)
                throws DataFormatException,
                       IOException
```
    Description copied from interface: DataStructure
    
    Write out the data structure to the stream, using the format defined in the I2P data structure specification.
    
    Parameters:
    
    out - stream to write to
    
    Throws:
    
    DataFormatException - if the data was incomplete or not yet ready to be written
    
    IOException - if there was a problem writing to the stream
  - writeBytes
```
public int writeBytes(byte[] target,
                      int offset)
```
    Returns:
    
    the written length (NOT the new offset)
  - readBytes
```
public int readBytes(byte[] source,
                     int offset)
              throws DataFormatException
```
    Throws:
    
    IllegalStateException - if already set
    
    DataFormatException
  - size
```
public int size()
```
  - toKeyCertificate
```
public KeyCertificate toKeyCertificate()
                                throws DataFormatException
```
    Up-convert this to a KeyCertificate
    
    Throws:
    
    DataFormatException - if cert type != CERTIFICATE_TYPE_KEY
    
    Since:
    
    0.9.12
  - equals
```
public boolean equals(Object object)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object

Constructors
Constructor	Description
`Certificate()`
`Certificate(int type, byte[] payload)`

Class Certificate

Field Summary

Constructor Summary

Method Summary

Methods inherited from class net.i2p.data.DataStructureImpl

Methods inherited from class java.lang.Object

Field Detail

NULL_CERT

_type

_payload

CERTIFICATE_TYPE_NULL

CERTIFICATE_TYPE_HASHCASH

CERTIFICATE_TYPE_HIDDEN

CERTIFICATE_TYPE_SIGNED

CERTIFICATE_LENGTH_SIGNED_WITH_HASH

CERTIFICATE_TYPE_MULTIPLE

CERTIFICATE_TYPE_KEY

Constructor Detail

Certificate

Certificate

Method Detail

create

create

getCertificateType

setCertificateType

getPayload

setPayload

readBytes

writeBytes

writeBytes

readBytes

size

toKeyCertificate

equals

hashCode

toString