corda / net.corda.core.contracts / PrivacySalt

PrivacySalt

class PrivacySalt : OpaqueBytes

A privacy salt is required to compute nonces per transaction component in order to ensure that an adversary cannot use brute force techniques and reveal the content of a Merkle-leaf hashed value. Because this salt serves the role of the seed to compute nonces, its size and entropy should be equal to the underlying hash function used for Merkle tree generation, currently SecureHash.SHA256, which has an output of 32 bytes. There are two constructors, one that generates a new 32-bytes random salt, and another that takes a ByteArray input. The latter is required in cases where the salt value needs to be pre-generated (agreed between transacting parties), but it is highlighted that one should always ensure it has sufficient entropy.

Constructors

<init>

PrivacySalt()

Constructs a salt with a randomly-generated 32 byte value.

PrivacySalt(bytes: ByteArray)

A privacy salt is required to compute nonces per transaction component in order to ensure that an adversary cannot use brute force techniques and reveal the content of a Merkle-leaf hashed value. Because this salt serves the role of the seed to compute nonces, its size and entropy should be equal to the underlying hash function used for Merkle tree generation, currently SecureHash.SHA256, which has an output of 32 bytes. There are two constructors, one that generates a new 32-bytes random salt, and another that takes a ByteArray input. The latter is required in cases where the salt value needs to be pre-generated (agreed between transacting parties), but it is highlighted that one should always ensure it has sufficient entropy.

Inherited Properties

bytes

val bytes: ByteArray

The bytes are always cloned so that this object becomes immutable. This has been done to prevent tampering with entities such as net.corda.core.crypto.SecureHash and net.corda.core.contracts.PrivacySalt, as well as preserve the integrity of our hash constants net.corda.core.crypto.SecureHash.zeroHash and net.corda.core.crypto.SecureHash.allOnesHash.

Extension Functions

contextLogger

fun Any.contextLogger(): Logger

When called from a companion object, returns the logger for the enclosing class.

deserialize

fun <T : Any> ByteSequence.deserialize(serializationFactory: SerializationFactory = SerializationFactory.defaultFactory, context: SerializationContext = serializationFactory.defaultContext): T

Convenience extension method for deserializing a ByteSequence, utilising the defaults.

deserializeWithCompatibleContext

fun <T : Any> ByteSequence.deserializeWithCompatibleContext(serializationFactory: SerializationFactory = SerializationFactory.defaultFactory, context: SerializationContext = serializationFactory.defaultContext): ObjectWithCompatibleContext<T>

Additionally returns SerializationContext which was used for encoding. It might be helpful to know SerializationContext to use the same encoding in the reply.

sha256

fun OpaqueBytes.sha256(): SHA256

Compute the SHA-256 hash for the contents of the OpaqueBytes.