org.plasmalabs.crypto.generation.mnemonic.Entropy.scala Maven / Gradle / Ivy
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package org.plasmalabs.crypto.generation.mnemonic
import cats.implicits._
import org.plasmalabs.crypto.generation.mnemonic.EntropyFailures.InvalidByteSize
import org.plasmalabs.crypto.generation.mnemonic.Language.LanguageWordList
import java.util.UUID
/**
* Wrapper around the entropy contained represented by an array of bytes
* @param value the underlying bytes of entropy
*/
case class Entropy(value: Array[Byte])
object Entropy {
/**
* Generate an Entropy of the specified size.
* @param size one of the values defined in [[MnemonicSizes]]
* @return the generated Entropy
*/
def generate(size: MnemonicSize = MnemonicSizes.words12): Entropy = {
val numBytes = size.entropyLength / byteLen
val r = new Array[Byte](numBytes)
new java.security.SecureRandom().nextBytes(r) // overrides r
Entropy(r)
}
/**
* Generate an mnemonic string from an `Entropy` value
*
* @param entropy The entropy value from which to compute the mnemonic
* @param language The language of the mnemonic string
* @return
*/
def toMnemonicString(
entropy: Entropy,
language: Language = Language.English
): Either[EntropyFailure, IndexedSeq[String]] =
for {
size <- sizeFromEntropyLength(entropy.value.length.toInt)
phrase <- Phrase.fromEntropy(entropy, size, language).leftMap(EntropyFailures.PhraseToEntropyFailure.apply)
} yield phrase.value
/**
* Instantiates an 'Entropy' value from a string by validating the string to a mnemonic phrase and then deriving
* the entropy of the string according to the BIP-39 wordlists
* @param mnemonic string to be decoded to a mnemonic
* @param language applicable language to pull the wordlist for
* @return either an entropy encode failure or the entropy for use in key derivation
*/
def fromMnemonicString(
mnemonic: String,
language: Language = Language.English
): Either[EntropyFailure, Entropy] =
Phrase
.validated(mnemonic, language)
.map(Entropy.unsafeFromPhrase)
.leftMap(EntropyFailures.PhraseToEntropyFailure.apply)
/**
* Instantiates a 128-bit `Entropy` (12 word) value from a given `UUID`.
* @param uuid a UUID to convert into `Entropy`
* @return an `Entropy` value
*/
def fromUuid(uuid: UUID): Entropy =
Entropy(
uuid.toString
.filterNot("-".toSet)
.grouped(2)
.map(Integer.parseInt(_, 16).toByte)
.toArray
)
/**
* Instantiates an `Entropy` value from byte data for an expected mnemonic size.
* @param bytes the byte data to convert into entropy
* @return either a `ValidationFailure` if the byte data is invalid or `Entropy` if it is valid
*/
def fromBytes(bytes: Array[Byte]): Either[EntropyFailure, Entropy] = for {
_ <- sizeFromEntropyLength(bytes.length)
entropy = Entropy(bytes)
} yield entropy
/**
* Instantiates an `Entropy` value from a `Phrase`, `LanguageWordList`, and `MnemonicSize`.
*
* Note: the phrase is not re-validated for the given `LanguageWordList` and `MnemonicSize`
*
* @param phrase the mnemonic phrase to get entropy from
* @return the underlying entropy of the mnemonic phrase
*/
private[mnemonic] def unsafeFromPhrase(phrase: Phrase): Entropy =
Entropy(
Phrase
.toBinaryString(phrase)
._1 // extract the entropy from the Phrase
.grouped(byteLen) // group into bytes
.map(Integer.parseInt(_, 2).toByte) // interpret the binary string as a List[Byte]
.toArray
)
private[mnemonic] def sizeFromEntropyLength(entropyByteLength: Int): Either[EntropyFailure, MnemonicSize] =
entropyByteLength match {
case 16 => Right(MnemonicSizes.words12)
case 20 => Right(MnemonicSizes.words15)
case 24 => Right(MnemonicSizes.words18)
case 28 => Right(MnemonicSizes.words21)
case 32 => Right(MnemonicSizes.words24)
case _ => Left(InvalidByteSize)
}
}
sealed trait EntropyFailure extends RuntimeException
/**
* Enumeration of errors that can be produced when creating a mnemonic from entropy.
*/
object EntropyFailures {
case object InvalidByteSize extends EntropyFailure
case class PhraseToEntropyFailure(failure: PhraseFailure) extends EntropyFailure
case class WordListFailure(failure: LanguageWordList.ValidationFailure) extends EntropyFailure
case object InvalidSizeMismatch extends EntropyFailure
}