SHA1Hash (Javadocs [I2P+ 2.13.0+] - API Version 0.9.70+)

java.lang.Object
- net.i2p.data.SimpleDataStructure
- - net.i2p.crypto.SHA1Hash

All Implemented Interfaces:
DataStructure
Direct Known Subclasses:
InfoHash, NID, TokenKey
```
public class SHA1Hash
extends SimpleDataStructure
```
I2P data structure for SHA-1 hash values. This class provides a SimpleDataStructure wrapper for 20-byte SHA-1 hashes used throughout I2P for data integrity and identification purposes. It extends SimpleDataStructure to support I2P's serialization framework and provides efficient caching of hash codes.
Common uses include:
- Router and destination identifiers
- Message integrity verification
- Data structure indexing and lookup

Field Summary
Fields
Modifier and Type Field and Description
static int HASH_LENGTH
HASH_LENGTH.
- Fields inherited from class net.i2p.data.SimpleDataStructure
  _data

Fields
Modifier and Type	Field and Description
`static int`	`HASH_LENGTH` HASH_LENGTH.

Constructor Summary
Constructors
Constructor and Description
SHA1Hash()
Create an empty SHA-1 hash (data is null).
SHA1Hash(byte[] data)
Create a SHA-1 hash from the given data.

Constructors
Constructor and Description
`SHA1Hash()` Create an empty SHA-1 hash (data is null).
`SHA1Hash(byte[] data)` Create a SHA-1 hash from the given data.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`int`	`hashCode()` a Hash is a hash, so just use the first 4 bytes for speed
`int`	`length()` Hash length in bytes.
`void`	`readBytes(InputStream in)` readBytes.
`void`	`setData(byte[] data)` IllegalArgumentException if data is not 20 bytes (null is ok).

Methods inherited from class net.i2p.data.SimpleDataStructure
calculateHash, equals, fromBase64, fromByteArray, getData, read, toBase64, toByteArray, toString, writeBytes

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

- Field Detail
  - HASH_LENGTH
```
public static final int HASH_LENGTH
```
    HASH_LENGTH.
    See Also:
    Constant Field Values
- Constructor Detail
  - SHA1Hash
```
public SHA1Hash()
```
    Create an empty SHA-1 hash (data is null).
  - SHA1Hash
```
public SHA1Hash(byte[] data)
```
    Create a SHA-1 hash from the given data.
    Parameters:
    data - the 20-byte SHA-1 hash data
    Throws:
    IllegalArgumentException - if data is not 20 bytes (null is ok)
- Method Detail
  - hashCode
```
public int hashCode()
```
    a Hash is a hash, so just use the first 4 bytes for speed
    Overrides:
    hashCode in class SimpleDataStructure
    Returns:
    the hash code
  - length
```
public int length()
```
    Hash length in bytes.
    Specified by:
    length in class SimpleDataStructure
    Returns:
    the hash length in bytes
  - readBytes
```
public void readBytes(InputStream in)
               throws DataFormatException,
                      IOException
```
    readBytes.
    Specified by:
    readBytes in interface DataStructure
    Overrides:
    readBytes in class SimpleDataStructure
    Parameters:
    in - the stream to read
    Throws:
    DataFormatException - if the data is improperly formatted
    IOException - if there was a problem reading the stream
  - setData
```
public void setData(byte[] data)
```
    IllegalArgumentException if data is not 20 bytes (null is ok).
    Overrides:
    setData in class SimpleDataStructure
    Parameters:
    data - of correct length, or null
    Throws:
    IllegalArgumentException - if data is not 20 bytes (null is ok)

Class SHA1Hash

Field Summary

Fields inherited from class net.i2p.data.SimpleDataStructure

Constructor Summary

Method Summary

Methods inherited from class net.i2p.data.SimpleDataStructure

Methods inherited from class java.lang.Object

Field Detail

HASH_LENGTH

Constructor Detail

SHA1Hash

SHA1Hash

Method Detail

hashCode

length

readBytes

setData