Package convex.core.data

Class SignedData<T extends ACell>

java.lang.Object

convex.core.data.AObject

convex.core.data.ACell

convex.core.data.ACountable<E>

convex.core.data.ADataStructure<MapEntry<K,V>>

convex.core.data.AMap<Keyword,ACell>

convex.core.data.ARecord

convex.core.data.SignedData<T>

Type Parameters:

T - The type of the signed object

All Implemented Interfaces:

IAssociative<Keyword,ACell>, IValidated, IWriteable, Map<Keyword,ACell>

public final class SignedData<T extends ACell>
extends ARecord

Node representing a signed data object. A signed data object encapsulates:

• An Address that identifies the signer
• A digital signature
• An underlying Cell that has been signed.

The SignedData instance is considered valid if the signature can be successfully validated for the given Address and data value, and if so can be taken as a cryptographic proof that the signature was created by someone in possession of the corresponding private key. Note we currently go via a Ref here for a few reasons: - It guarantees we have a hash for signing - It makes the SignedData object implementation/representation independent of the value type - It creates a possibility of structural sharing for transaction values excluding signatures Binary representation:

1. 1 byte - Tag.SIGNED_DATA tag
2. 32 bytes - Public Key of signer
3. 64 bytes - raw Signature data
4. 1+ bytes - Data Value Ref (may be embedded)

SECURITY: signing requires presence of a local keypair TODO: SECURITY: any persistence forces validation of Signature??

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K extends Object,V extends Object>

Field Summary

Fields inherited from class convex.core.data.ARecord

DEFAULT_VALUE

Fields inherited from class convex.core.data.ADataStructure

count

Fields inherited from class convex.core.data.ACell

cachedRef, EMPTY_ARRAY

Fields inherited from class convex.core.data.AObject

encoding

Method Summary

Modifier and Type	Method	Description
boolean	checkSignature()	Validates the signature in this SignedData instance.
static SignedData<ATransaction>	create(AKeyPair kp, ASignature sig, Ref<ATransaction> ref)
static <T extends ACell> SignedData<T>	create(AKeyPair keyPair, T value2)
static <T extends ACell> SignedData<T>	create(AccountKey address, ASignature sig, Ref<T> ref)	Creates a SignedData object with the given parameters.
static <T extends ACell> SignedData<T>	createWithRef(AKeyPair keyPair, Ref<T> ref)	Signs a data value Ref with the given keypair.
int	encode(byte[] bs, int pos)	Writes this Cell's encoding to a byte array, including a tag byte which will be written first.
int	encodeRaw(byte[] bs, int pos)	Writes the raw fields of this record in declared order
int	estimatedEncodingSize()	Estimate the encoded data size for this Cell.
ACell	get(Keyword key)	Gets the record field content for a given key, or null if not found.
AccountKey	getAccountKey()	Gets the public key of the signer.
RecordFormat	getFormat()	Gets the RecordFormat instance that describes this Record's layout
<R extends ACell> Ref<R>	getRef(int i)	Gets a numbered child Ref from within this Cell.
final int	getRefCount()	Gets the number of Refs contained within this Cell.
ASignature	getSignature()	Gets the Signature that formed part of this SignedData object
byte	getTag()	Gets the tag byte for this record type.
T	getValue()	Gets the signed value object encapsulated by this SignedData object.
Ref<T>	getValueRef()
boolean	isCanonical()	Returns true if this Cell is in a canonical representation for message writing.
final boolean	isCVMValue()	Returns true if this Cell represents a first class CVM Value.
boolean	isEmbedded()	SignedData is not embedded.
boolean	isSignatureChecked()	Checks if the signature has already gone through verification.
static <T extends ACell> SignedData<T>	read(Blob b, int pos)	Reads a SignedData instance from the given Blob encoding
SignedData<T>	updateRefs(IRefFunction func)	Updates all Refs in this object using the given function.
void	validate()	Validates the complete structure of this object.
void	validateCell()	Validates the local structure and invariants of this cell.
void	validateSignature()

Methods inherited from class convex.core.data.ARecord

accumulateEntrySet, accumulateKeySet, accumulateValues, assoc, assocEntry, containsKey, containsValue, dissoc, dissoc, empty, entryAt, entrySet, forEach, get, getEntry, getEntryByHash, getKeyRefEntry, getKeys, getType, getValuesArray, keySet, reduceEntries, reduceValues, toCanonical, toHashMap, values

Methods inherited from class convex.core.data.AMap

clear, conj, containsKey, containsKeyRef, containsValue, entryVector, filterValues, get, get, get, getElementRef, merge, print, put, putAll, remove, slice, slice

Methods inherited from class convex.core.data.ADataStructure

checkIndex, conjAll, count, isEmpty, size, toCVMString

Methods inherited from class convex.core.data.ACell

announce, announce, attachMemorySize, attachRef, cachedEncoding, cachedHash, calcMemorySize, createAnnounced, createEncoding, createPersisted, createPersisted, createRef, equals, equals, getCanonical, getChildRefs, getEncoding, getEncodingLength, getHash, getMemorySize, getRef, hashCode, isCompletelyEncoded, mark, mark, toString

Methods inherited from class convex.core.data.AObject

attachEncoding, print, print

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, equals, getOrDefault, hashCode, isEmpty, merge, putIfAbsent, remove, replace, replace, replaceAll, size

Method Details

createWithRef

public static <T extends ACell> SignedData<T> createWithRef(AKeyPair keyPair,
 Ref<T> ref)

Signs a data value Ref with the given keypair. SECURITY: Marks as already validated, since we just signed it.

Parameters:

keyPair - The public/private key pair of the signer.

ref - Ref to the data to sign

Returns:

SignedData object signed with the given key-pair

create

public static <T extends ACell> SignedData<T> create(AKeyPair keyPair,
 T value2)

create

public static <T extends ACell> SignedData<T> create(AccountKey address,
 ASignature sig,
 Ref<T> ref)

Creates a SignedData object with the given parameters. SECURITY: Not assumed to be valid.

Parameters:

address - Public Address of the signer

sig - Signature of the supplied data

ref - Ref to the data that has been signed

Returns:

A new SignedData object

create

public static SignedData<ATransaction> create(AKeyPair kp,
 ASignature sig,
 Ref<ATransaction> ref)

getValue

public T getValue()

Gets the signed value object encapsulated by this SignedData object. Does not check Signature.

Returns:

Data value that has been signed

getAccountKey

public AccountKey getAccountKey()

Gets the public key of the signer. If the signature is valid, this represents a cryptographic proof that the signer was in possession of the private key of this address.

Returns:

Public Key of signer.

getSignature

public ASignature getSignature()

Gets the Signature that formed part of this SignedData object

Returns:

Signature instance

get

public ACell get(Keyword key)

Description copied from class: ARecord

Gets the record field content for a given key, or null if not found.

Specified by:

get in class ARecord

Parameters:

key - Key to look up in this record

Returns:

Field value for the given key

encode

public int encode(byte[] bs,
 int pos)

Description copied from class: ACell

Writes this Cell's encoding to a byte array, including a tag byte which will be written first. Cell must be canonical, or else an error may occur.

Specified by:

encode in interface IWriteable

Specified by:

encode in class ACell

Parameters:

bs - A byte array to which to write the encoding

pos - The offset into the byte array

Returns:

New position after writing

encodeRaw

public int encodeRaw(byte[] bs,
 int pos)

Description copied from class: ARecord

Writes the raw fields of this record in declared order

Overrides:

encodeRaw in class ARecord

Parameters:

bs - Array to write to

pos - The offset into the byte array

Returns:

New position after writing

estimatedEncodingSize

public int estimatedEncodingSize()

Description copied from interface: IWriteable

Estimate the encoded data size for this Cell. Used for quickly sizing buffers. Implementations should try to return a size that is highly likely to contain the entire object when encoded, including the tag byte. Should not traverse soft Refs, i.e. must be usable on arbitrary partial data structures

Specified by:

estimatedEncodingSize in interface IWriteable

Overrides:

estimatedEncodingSize in class ARecord

Returns:

The estimated size for the binary representation of this object.

read

public static <T extends ACell> SignedData<T> read(Blob b,
 int pos)
                                            throws BadFormatException

Reads a SignedData instance from the given Blob encoding

Parameters:

b - Blob to read from

pos - Start position in Blob (location of tag byte)

Returns:

New decoded instance

Throws:

BadFormatException - In the event of any encoding error

checkSignature

public boolean checkSignature()

Validates the signature in this SignedData instance. Caches result

Returns:

true if valid, false otherwise

isSignatureChecked

public boolean isSignatureChecked()

Checks if the signature has already gone through verification. MAy or may not be a valid signature.

Returns:

true if valid, false otherwise

validateSignature

public void validateSignature()
                       throws BadSignatureException

Throws:

BadSignatureException

isCanonical

public boolean isCanonical()

Description copied from class: ACell

Returns true if this Cell is in a canonical representation for message writing. Non-canonical objects may be used on a temporary internal basis, they must always be converted to canonical representations for external use (e.g. Encoding).

Overrides:

isCanonical in class ARecord

Returns:

true if the object is in canonical format, false otherwise

isCVMValue

public final boolean isCVMValue()

Description copied from class: ACell

Returns true if this Cell represents a first class CVM Value. Sub-structural cells that are not themselves first class values should return false, pretty much everything else should return true. Note: CVM values might not be in a canonical format, e.g. temporary data structures

Overrides:

isCVMValue in class ARecord

Returns:

true if the object is a CVM Value, false otherwise

getRefCount

public final int getRefCount()

Description copied from class: ACell

Gets the number of Refs contained within this Cell. This number is final / immutable for any given instance and is defined by the Cell encoding rules. WARNING: may not be valid id Cell is not canonical Contained Refs may be either external or embedded.

Specified by:

getRefCount in class ACell

Returns:

The number of Refs in this Cell

getRef

public <R extends ACell> Ref<R> getRef(int i)

Description copied from class: ACell

Gets a numbered child Ref from within this Cell. WARNING: May be unreliable is cell is not canonical

Overrides:

getRef in class ACell

Type Parameters:

R - Type of referenced Cell

Parameters:

i - Index of ref to get

Returns:

The Ref at the specified index

updateRefs

public SignedData<T> updateRefs(IRefFunction func)

Description copied from class: ACell

Updates all Refs in this object using the given function. The function *must not* change the hash value of Refs, in order to ensure structural integrity of modified data structures. The implementation *should* re-attach any original encoding in order to prevent re-encoding or surplus hashing This is a building block for a very sneaky trick that enables use to do a lot of efficient operations on large trees of smart references. Must return the same object if no Refs are altered.

Overrides:

updateRefs in class ACell

Parameters:

func - Ref update function

Returns:

Cell with updated Refs

validate

public void validate()
              throws InvalidDataException

Description copied from interface: IValidated

Validates the complete structure of this object. It is necessary to ensure all child Refs are validated, so the general contract for validate is:

1. Call super.validate() - which will indirectly call validateCell()
2. Call validate() on any contained cells in this class

Specified by:

validate in interface IValidated

Overrides:

validate in class ACell

Throws:

InvalidDataException - If the data Value is invalid in any way

validateCell

public void validateCell()
                  throws InvalidDataException

Description copied from class: ACell

Validates the local structure and invariants of this cell. Called by validate() super implementation. Should validate directly contained data, but should not validate all other structure of this cell. In particular, should not traverse potentially missing child Refs.

Specified by:

validateCell in class ACell

Throws:

InvalidDataException - If the Cell is invalid

getValueRef

public Ref<T> getValueRef()

isEmbedded

public boolean isEmbedded()

SignedData is not embedded. We want to persist in store always to cache verification status

Overrides:

isEmbedded in class ACell

Returns:

Always false

getTag

public byte getTag()

Description copied from class: ARecord

Gets the tag byte for this record type. The Tag is the byte used to identify the record in the binary encoding.

Specified by:

getTag in class ARecord

Returns:

Record tag byte

getFormat

public RecordFormat getFormat()

Description copied from class: ARecord

Gets the RecordFormat instance that describes this Record's layout

Specified by:

getFormat in class ARecord

Returns:

RecordFormat instance