Class MultiHash

A protocol for differentiating outputs from various well-established cryptographic hash functions, addressing size + encoding considerations.

Inheritance

Object

MultiHash

Implements

IEquatable<MultiHash>

Inherited Members

Object.Equals(Object, Object)

Object.GetType()

Object.MemberwiseClone()

Object.ReferenceEquals(Object, Object)

Namespace: Ipfs

Assembly: Ipfs.Core.dll

Syntax

[JsonConverter(typeof(MultiHash.Json))]
public class MultiHash : IEquatable<MultiHash>

Remarks

See the HashingAlgorithm for supported algorithms.

Constructors

MultiHash(CodedInputStream)

Creates a new instance of the MultiHash class from the specified Google.Protobuf.CodedInputStream.

Declaration

public MultiHash(CodedInputStream stream)

Parameters

Type	Name	Description
Google.Protobuf.CodedInputStream	stream	A Google.Protobuf.CodedInputStream containing the binary representation of the MultiHash.

Remarks

Reads the binary representation of MultiHash from the stream.

The binary representation is a Varint of the Code, Varint of the DigestSize followed by the Digest.

When an unknown Code is encountered a new hashing algorithm is Register(String, Int32, Int32, Func<HashAlgorithm>). This new algorithm does not support matching nor computing a hash. This behaviour allows parsing of any well formed MultiHash even when the hashing algorithm is unknown.

MultiHash(Byte[])

Creates a new instance of the MultiHash class from the specified byte array.

Declaration

public MultiHash(byte[] buffer)

Parameters

Type	Name	Description
Byte[]	buffer	A sequence of bytes containing the binary representation of the MultiHash.

Remarks

Reads the binary representation of MultiHash from the buffer.

The binary representation is a Varint of the Code, Varint of the DigestSize followed by the Digest.

When an unknown Code is encountered a new hashing algorithm is Register(String, Int32, Int32, Func<HashAlgorithm>). This new algorithm does not support matching nor computing a hash. This behaviour allows parsing of any well formed MultiHash even when the hashing algorithm is unknown.

See Also

ToArray()

MultiHash(Stream)

Creates a new instance of the MultiHash class from the specified Stream.

Declaration

public MultiHash(Stream stream)

Parameters

Type	Name	Description
Stream	stream	A Stream containing the binary representation of the MultiHash.

Remarks

Reads the binary representation of MultiHash from the stream.

The binary representation is a Varint of the Code, Varint of the DigestSize followed by the Digest.

When an unknown Code is encountered a new hashing algorithm is Register(String, Int32, Int32, Func<HashAlgorithm>). This new algorithm does not support matching nor computing a hash. This behaviour allows parsing of any well formed MultiHash even when the hashing algorithm is unknown.

MultiHash(String)

Creates a new instance of the MultiHash class from the specified Base58 encoded String.

Declaration

public MultiHash(string s)

Parameters

Type	Name	Description
String	s	A Base58 encoded MultiHash.

Remarks

When an unknown Code is encountered a new hashing algorithm is Register(String, Int32, Int32, Func<HashAlgorithm>). This new algorithm does not support matching nor computing a hash. This behaviour allows parsing of any well formed MultiHash even when the hashing algorithm is unknown.

See Also

ToBase58()

MultiHash(String, Byte[])

Creates a new instance of the MultiHash class with the specified HashingAlgorithm and Digest value.

Declaration

public MultiHash(string algorithmName, byte[] digest)

Parameters

Type	Name	Description
String	algorithmName	A valid IPFS hashing algorithm name, e.g. "sha2-256" or "sha2-512".
Byte[]	digest	The digest value as a byte array.

Fields

DefaultAlgorithmName

The default hashing algorithm is "sha2-256".

Declaration

public const string DefaultAlgorithmName = "sha2-256"

Field Value

Type	Description
String

UnknownHashingAlgorithm

Occurs when an unknown hashing algorithm number is parsed.

Declaration

public static EventHandler<UnknownHashingAlgorithmEventArgs> UnknownHashingAlgorithm

Field Value

Type	Description
EventHandler<UnknownHashingAlgorithmEventArgs>

Properties

Algorithm

The hashing algorithm.

Declaration

public HashingAlgorithm Algorithm { get; }

Property Value

Type	Description
HashingAlgorithm	Details on the hashing algorithm.

Digest

The hashing algorithm's digest value.

Declaration

public byte[] Digest { get; }

Property Value

Type	Description
Byte[]	The output of the hashing algorithm.

IsIdentityHash

Determines if the identity hash algorithm is in use.

Declaration

public bool IsIdentityHash { get; }

Property Value

Type	Description
Boolean	true if the identity hash algorithm is used; otherwise, false.

Remarks

The identity hash is used to inline a small amount of data into a Cid. When true, the Digest is also the content.

Methods

ComputeHash(Byte[], String)

Generate the multihash for the specified byte array.

Declaration

public static MultiHash ComputeHash(byte[] data, string algorithmName = "sha2-256")

Parameters

Type	Name	Description
Byte[]	data	The byte array containing the data to hash.
String	algorithmName	The name of the hashing algorithm to use; defaults to DefaultAlgorithmName.

Returns

Type	Description
MultiHash	A MultiHash for the data.

ComputeHash(Stream, String)

Generate the multihash for the specified Stream.

Declaration

public static MultiHash ComputeHash(Stream data, string algorithmName = "sha2-256")

Parameters

Type	Name	Description
Stream	data	The Stream containing the data to hash.
String	algorithmName	The name of the hashing algorithm to use; defaults to DefaultAlgorithmName.

Returns

Type	Description
MultiHash	A MultiHash for the data.

Equals(MultiHash)

Declaration

public bool Equals(MultiHash that)

Parameters

Type	Name	Description
MultiHash	that

Returns

Type	Description
Boolean

Equals(Object)

Declaration

public override bool Equals(object obj)

Parameters

Type	Name	Description
Object	obj

Returns

Type	Description
Boolean

Overrides

Object.Equals(Object)

GetHashAlgorithm(String)

Gets the HashAlgorithm with the specified IPFS multi-hash name.

Declaration

public static HashAlgorithm GetHashAlgorithm(string name = "sha2-256")

Parameters

Type	Name	Description
String	name	The name of a hashing algorithm, see https://github.com/multiformats/multicodec/blob/master/table.csv for IPFS defined names.

Returns

Type	Description
HashAlgorithm	The hashing implementation associated with the name. After using the hashing algorithm it should be disposed.

Exceptions

Type	Condition
KeyNotFoundException	When name is not registered.

GetHashAlgorithmName(Int32)

Gets the name of hashing algorithm name with the specified code.

Declaration

public static string GetHashAlgorithmName(int code)

Parameters

Type	Name	Description
Int32	code	The code of a hashing algorithm, see https://github.com/multiformats/multicodec/blob/master/table.csv for IPFS defined codes.

Returns

Type	Description
String	The name assigned to code.

Exceptions

Type	Condition
KeyNotFoundException	When code is not registered.

GetHashCode()

Declaration

public override int GetHashCode()

Returns

Type	Description
Int32

Overrides

Object.GetHashCode()

Matches(Byte[])

Determines if the data matches the hash.

Declaration

public bool Matches(byte[] data)

Parameters

Type	Name	Description
Byte[]	data	The data to check.

Returns

Type	Description
Boolean	true if the data matches the MultiHash; otherwise, false.

Remarks

Matches is used to ensure data integrity.

Matches(Stream)

Determines if the stream data matches the hash.

Declaration

public bool Matches(Stream data)

Parameters

Type	Name	Description
Stream	data	The Stream containing the data to check.

Returns

Type	Description
Boolean	true if the data matches the MultiHash; otherwise, false.

Remarks

Matches is used to ensure data integrity.

ToArray()

Returns the IPFS binary representation as a byte array.

Declaration

public byte[] ToArray()

Returns

Type	Description
Byte[]	A byte array.

Remarks

The binary representation is a sequence of MultiHash.

ToBase32()

Returns the Base32 encoding of the MultiHash.

Declaration

public string ToBase32()

Returns

Type	Description
String	The Base32 representation of the MultiHash.

ToBase58()

Returns the Base58 encoding of the MultiHash.

Declaration

public string ToBase58()

Returns

Type	Description
String	The Base58 representation of the MultiHash.

ToString()

Returns the Base58 encoding of the MultiHash.

Declaration

public override string ToString()

Returns

Type	Description
String	A base-58 representaton of the MultiHash.

Overrides

Object.ToString()

See Also

ToBase58()

Write(CodedOutputStream)

Writes the binary representation of the multihash to the specified Google.Protobuf.CodedOutputStream.

Declaration

public void Write(CodedOutputStream stream)

Parameters

Type	Name	Description
Google.Protobuf.CodedOutputStream	stream	The Google.Protobuf.CodedOutputStream to write to.

Remarks

The binary representation is a Varint of the Code, Varint of the DigestSize followed by the Digest.

Write(Stream)

Writes the binary representation of the multihash to the specified Stream.

Declaration

public void Write(Stream stream)

Parameters

Type	Name	Description
Stream	stream	The Stream to write to.

Remarks

The binary representation is a 1-byte Code, 1-byte DigestSize followed by the Digest.

Operators

Equality(MultiHash, MultiHash)

Value equality.

Declaration

public static bool operator ==(MultiHash a, MultiHash b)

Parameters

Type	Name	Description
MultiHash	a
MultiHash	b

Returns

Type	Description
Boolean

Implicit(String to MultiHash)

Implicit casting of a String to a MultiHash.

Declaration

public static implicit operator MultiHash(string s)

Parameters

Type	Name	Description
String	s	A Base58 encoded MultiHash.

Returns

Type	Description
MultiHash	A new MultiHash.

Remarks

Equivalent to

new MultiHash(s)

Inequality(MultiHash, MultiHash)

Value inequality.

Declaration

public static bool operator !=(MultiHash a, MultiHash b)

Parameters

Type	Name	Description
MultiHash	a
MultiHash	b

Returns

Type	Description
Boolean

Implements

System.IEquatable<T>

See Also

https://github.com/jbenet/multihash