com.arxanfintech.common.crypto

类 Hash

java.lang.Object

com.arxanfintech.common.crypto.Hash

public class Hash
extends java.lang.Object

A Hash identifies objects, that is blocks and transactions, in the ledger. Technically it is a double SHA256 digest of the object's content.

字段概要

字段

限定符和类型	字段和说明
static Hash	INVALID

构造器概要

构造器

限定符	构造器和说明
	Hash(byte[] hash) create a Hash from a digest
protected	Hash(byte[] hash, boolean safe) An unsafe constructor of a Hash from a byte array.
	Hash(java.lang.String hex) create a Hash from a hexadecimal representation of the digest Note that this is in the reverse byte order of the internal binary representation.

方法概要

限定符和类型	方法和说明
static Hash	createFromSafeArray(byte[] hash) Unsafe constructor of a Hash.
boolean	equals(java.lang.Object o)
static byte[]	hash(byte[] data) SHA256 hash of arbitrary data
static byte[]	hash(byte[] data, int offset, int len) SHA256 hash of arbitrary data
int	hashCode()
static Hash	merge(Hash a, Hash b) Merge two Hashes into one for Merkle Tree calculation
static Hash	of(byte[] data) Create a Hash with double SHA256 hash of arbitrary data
java.math.BigInteger	toBigInteger() Convert a Hash into a big positive integer.
byte[]	toByteArray() Safe access to the digest stored in a Hash
java.lang.String	toString()
java.lang.String	toUuidString() UUID created from the first 128 bits of SHA256
byte[]	unsafeGetArray() Unsafe get of the internal byte array.

从类继承的方法 java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

字段详细资料

INVALID

public static final Hash INVALID

构造器详细资料

Hash

public Hash(byte[] hash)

create a Hash from a digest

参数:

hash - - digest must be 32 bytes long

Hash

public Hash(java.lang.String hex)

create a Hash from a hexadecimal representation of the digest Note that this is in the reverse byte order of the internal binary representation.

参数:

hex - - a digest as a 64 character hexadecimal sequence in reverse byte order.

Hash

protected Hash(byte[] hash,
               boolean safe)

An unsafe constructor of a Hash from a byte array. Unsafe as it does not copy the array but keeps reference to it. It is only used in TID and BID

参数:

hash - - a 32 byte digest

safe - - a dummy paramater to distinguish this unsafe constructor from the safe one.

方法详细资料

unsafeGetArray

public byte[] unsafeGetArray()

Unsafe get of the internal byte array. Use this with extreme care and only if you are sure that the content will not be modified as that would lead to hard to locate bugs by shared mutable data. The only reason this method exists is that the code uses lots of Hashes avoiding unnecesary copy of their content significantly reduces memory footprint and increases performance. There is a risk tradoff however.

返回:

internal representation of Hash. DO NOT ALTER

createFromSafeArray

public static Hash createFromSafeArray(byte[] hash)

Unsafe constructor of a Hash. Use this with extreme care and only if you are sure that the byte array in parameter will not be modified elswhere after calling this as that would lead to hard to locate bugs by shared mutable data. The only reason this method exists is that the code uses lots of Hashes avoiding unnecessary copy of their content significantly reduces memory footprint and increases performance. There is a risk tradeoff however.

参数:

hash - a digest. DO NOT ALTER the array after creating a Hash with it.

返回:

a new Hash that shares internal representation with the parameter byte array.

merge

public static Hash merge(Hash a,
                         Hash b)

Merge two Hashes into one for Merkle Tree calculation

参数:

a - - a Hash

b - - another Hash

返回:

SHA256(SHA256(a||b))

hash

public static byte[] hash(byte[] data,
                          int offset,
                          int len)

SHA256 hash of arbitrary data

参数:

data - arbitary data

offset - start hashing at this offset (0 starts)

len - hash len number of bytes

返回:

SHA256(data)

hash

public static byte[] hash(byte[] data)

SHA256 hash of arbitrary data

参数:

data - arbitrary data

返回:

SHA256(data)

of

public static Hash of(byte[] data)

Create a Hash with double SHA256 hash of arbitrary data

参数:

data - arbitrary data

返回:

a Hash initialized with SHA256(SHA256(data))

toUuidString

public java.lang.String toUuidString()

UUID created from the first 128 bits of SHA256

返回:

String

toByteArray

public byte[] toByteArray()

Safe access to the digest stored in a Hash

返回:

a copy of the internal digest in Hash

toBigInteger

public java.math.BigInteger toBigInteger()

Convert a Hash into a big positive integer. See HyperledgerHeader for its use for proof-of-work.

返回:

Hash as big positive integer

toString

public java.lang.String toString()

覆盖:

toString 在类中 java.lang.Object

hashCode

public int hashCode()

覆盖:

hashCode 在类中 java.lang.Object

equals

public boolean equals(java.lang.Object o)

覆盖:

equals 在类中 java.lang.Object