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-rw-r--r--taler-kotlin-android/src/main/java/net/taler/common/Bech32.kt133
1 files changed, 79 insertions, 54 deletions
diff --git a/taler-kotlin-android/src/main/java/net/taler/common/Bech32.kt b/taler-kotlin-android/src/main/java/net/taler/common/Bech32.kt
index 32885df..4b77f85 100644
--- a/taler-kotlin-android/src/main/java/net/taler/common/Bech32.kt
+++ b/taler-kotlin-android/src/main/java/net/taler/common/Bech32.kt
@@ -13,6 +13,7 @@
* You should have received a copy of the GNU General Public License along with
* GNU Taler; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
*/
+
// Copyright (c) 2020 Figure Technologies Inc.
// The contents of this file were derived from an implementation
// by the btcsuite developers https://github.com/btcsuite/btcutil.
@@ -23,27 +24,17 @@
// modified version of https://gist.github.com/iramiller/4ebfcdfbc332a9722c4a4abeb4e16454
-import net.taler.common.CyptoUtils
+package net.taler.common
+
+import java.util.Locale.ROOT
import kotlin.experimental.and
import kotlin.experimental.or
-
infix fun Int.min(b: Int): Int = b.takeIf { this > b } ?: this
infix fun UByte.shl(bitCount: Int) = ((this.toInt() shl bitCount) and 0xff).toUByte()
infix fun UByte.shr(bitCount: Int) = (this.toInt() shr bitCount).toUByte()
/**
- * Given an array of bytes, associate an HRP and return a Bech32Data instance.
- */
-fun ByteArray.toBech32Data(hrp: String) =
- Bech32Data(hrp, Bech32.convertBits(this, 8, 5, true))
-
-/**
- * Using a string in bech32 encoded address format, parses out and returns a Bech32Data instance
- */
-fun String.toBech32Data() = Bech32.decode(this)
-
-/**
* Bech32 Data encoding instance containing data for encoding as well as a human readable prefix
*/
data class Bech32Data(val hrp: String, val fiveBitData: ByteArray) {
@@ -71,6 +62,30 @@ data class Bech32Data(val hrp: String, val fiveBitData: ByteArray) {
override fun toString(): String {
return "bech32 : ${this.address}\nhuman: ${this.hrp} \nbytes"
}
+
+ override fun equals(other: Any?): Boolean {
+ if (this === other) return true
+ if (javaClass != other?.javaClass) return false
+
+ other as Bech32Data
+
+ if (hrp != other.hrp) return false
+ if (!fiveBitData.contentEquals(other.fiveBitData)) return false
+ if (!data.contentEquals(other.data)) return false
+ if (address != other.address) return false
+ if (!checksum.contentEquals(other.checksum)) return false
+
+ return true
+ }
+
+ override fun hashCode(): Int {
+ var result = hrp.hashCode()
+ result = 31 * result + fiveBitData.contentHashCode()
+ result = 31 * result + data.contentHashCode()
+ result = 31 * result + address.hashCode()
+ result = 31 * result + checksum.contentHashCode()
+ return result
+ }
}
/**
@@ -80,32 +95,32 @@ class Bech32 {
companion object {
const val CHECKSUM_SIZE = 6
- const val MIN_VALID_LENGTH = 8
- const val MAX_VALID_LENGTH = 90
+ private const val MIN_VALID_LENGTH = 8
+ private const val MAX_VALID_LENGTH = 90
const val MIN_VALID_CODEPOINT = 33
- const val MAX_VALID_CODEPOINT = 126
+ private const val MAX_VALID_CODEPOINT = 126
const val charset = "qpzry9x8gf2tvdw0s3jn54khce6mua7l"
- val gen = intArrayOf(0x3b6a57b2, 0x26508e6d, 0x1ea119fa, 0x3d4233dd, 0x2a1462b3)
+ private val gen = intArrayOf(0x3b6a57b2, 0x26508e6d, 0x1ea119fa, 0x3d4233dd, 0x2a1462b3)
fun generateFakeSegwitAddress(reservePub: String?, addr: String): List<String> {
- if (reservePub == null || reservePub.isEmpty()) return listOf<String>()
+ if (reservePub == null || reservePub.isEmpty()) return listOf()
val pub = CyptoUtils.decodeCrock(reservePub)
if (pub.size != 32) return listOf()
- val first_rnd = pub.copyOfRange(0,4)
- val second_rnd = pub.copyOfRange(0,4)
+ val firstRnd = pub.copyOfRange(0, 4)
+ val secondRnd = pub.copyOfRange(0, 4)
- first_rnd[0] = first_rnd[0].and(0b0111_1111);
- second_rnd[0] = second_rnd[0].or(0b1000_0000.toByte());
+ firstRnd[0] = firstRnd[0].and(0b0111_1111)
+ secondRnd[0] = secondRnd[0].or(0b1000_0000.toByte())
- val first_part = ByteArray(20);
- first_rnd.copyInto( first_part, 0, 0, 4)
- pub.copyInto( first_part, 4, 0, 16)
+ val firstPart = ByteArray(20)
+ firstRnd.copyInto(firstPart, 0, 0, 4)
+ pub.copyInto(firstPart, 4, 0, 16)
- val second_part = ByteArray(20);
- second_rnd.copyInto( second_part, 0, 0, 4)
- pub.copyInto( second_part, 4, 16, 32)
+ val secondPart = ByteArray(20)
+ secondRnd.copyInto(secondPart, 0, 0, 4)
+ pub.copyInto(secondPart, 4, 16, 32)
val zero = ByteArray(1)
zero[0] = 0
@@ -117,8 +132,8 @@ class Bech32 {
}
return listOf(
- Bech32Data(hrp, zero + convertBits(first_part, 8, 5, true)).address,
- Bech32Data(hrp, zero + convertBits(second_part, 8, 5, true)).address,
+ Bech32Data(hrp, zero + convertBits(firstPart, 8, 5, true)).address,
+ Bech32Data(hrp, zero + convertBits(secondPart, 8, 5, true)).address,
)
}
@@ -126,22 +141,31 @@ class Bech32 {
* Decodes a Bech32 String
*/
fun decode(bech32: String): Bech32Data {
- require(bech32.length >= MIN_VALID_LENGTH && bech32.length <= MAX_VALID_LENGTH) { "invalid bech32 string length" }
- require(bech32.toCharArray().none { c -> c.toInt() < MIN_VALID_CODEPOINT || c.toInt() > MAX_VALID_CODEPOINT })
- { "invalid character in bech32: ${bech32.toCharArray().map { c -> c.toInt() }
- .filter { c -> c.toInt() < MIN_VALID_CODEPOINT || c.toInt() > MAX_VALID_CODEPOINT }}" }
+ require(bech32.length in MIN_VALID_LENGTH..MAX_VALID_LENGTH) { "invalid bech32 string length" }
+ require(bech32.toCharArray()
+ .none { c -> c.code < MIN_VALID_CODEPOINT || c.code > MAX_VALID_CODEPOINT })
+ {
+ "invalid character in bech32: ${
+ bech32.toCharArray().map { c -> c.code }
+ .filter { c -> c < MIN_VALID_CODEPOINT || c > MAX_VALID_CODEPOINT }
+ }"
+ }
- require(bech32.equals(bech32.toLowerCase()) || bech32.equals(bech32.toUpperCase()))
+ require(bech32 == bech32.lowercase(ROOT) || bech32 == bech32.uppercase(ROOT))
{ "bech32 must be either all upper or lower case" }
- require(bech32.substring(1).dropLast(CHECKSUM_SIZE).contains('1')) { "invalid index of '1'" }
+ require(bech32.substring(1).dropLast(CHECKSUM_SIZE)
+ .contains('1')) { "invalid index of '1'" }
- val hrp = bech32.substringBeforeLast('1').toLowerCase()
- val dataString = bech32.substringAfterLast('1').toLowerCase()
+ val hrp = bech32.substringBeforeLast('1').lowercase(ROOT)
+ val dataString = bech32.substringAfterLast('1').lowercase(ROOT)
- require(dataString.toCharArray().all { c -> charset.contains(c) }) { "invalid data encoding character in bech32"}
+ require(dataString.toCharArray()
+ .all { c -> charset.contains(c) }) { "invalid data encoding character in bech32" }
val dataBytes = dataString.map { c -> charset.indexOf(c).toByte() }.toByteArray()
- val checkBytes = dataString.takeLast(CHECKSUM_SIZE).map { c -> charset.indexOf(c).toByte() }.toByteArray()
+ val checkBytes =
+ dataString.takeLast(CHECKSUM_SIZE).map { c -> charset.indexOf(c).toByte() }
+ .toByteArray()
val actualSum = checksum(hrp, dataBytes.dropLast(CHECKSUM_SIZE).toTypedArray())
require(1 == polymod(expandHrp(hrp).plus(dataBytes.map { d -> d.toInt() }))) { "checksum failed: $checkBytes != $actualSum" }
@@ -154,10 +178,10 @@ class Bech32 {
* This process is used to convert from base64 (from 8) to base32 (to 5) or the inverse.
*/
fun convertBits(data: ByteArray, fromBits: Int, toBits: Int, pad: Boolean): ByteArray {
- require (fromBits in 1..8 && toBits in 1..8) { "only bit groups between 1 and 8 are supported"}
+ require(fromBits in 1..8 && toBits in 1..8) { "only bit groups between 1 and 8 are supported" }
// resulting bytes with each containing the toBits bits from the input set.
- var regrouped = arrayListOf<Byte>()
+ val regrouped = arrayListOf<Byte>()
var nextByte = 0.toUByte()
var filledBits = 0
@@ -174,8 +198,9 @@ class Bech32 {
val remainToBits = toBits - filledBits
// we extract the remaining bits unless that is more than we need.
- val toExtract = remainFromBits.takeUnless { remainToBits < remainFromBits } ?: remainToBits
- check(toExtract >= 0) { "extract should be positive"}
+ val toExtract =
+ remainFromBits.takeUnless { remainToBits < remainFromBits } ?: remainToBits
+ check(toExtract >= 0) { "extract should be positive" }
// move existing bits to the left to make room for bits toExtract, copy in bits to extract
nextByte = (nextByte shl toExtract) or (b shr (8 - toExtract))
@@ -218,24 +243,24 @@ class Bech32 {
* Calculates a bech32 checksum based on BIP 173 specification
*/
fun checksum(hrp: String, data: Array<Byte>): ByteArray {
- var values = expandHrp(hrp)
+ val values = expandHrp(hrp)
.plus(data.map { d -> d.toInt() })
- .plus(Array<Int>(6){ _ -> 0}.toIntArray())
+ .plus(Array(6) { 0 }.toIntArray())
- var poly = polymod(values) xor 1
+ val poly = polymod(values) xor 1
return (0..5).map {
- ((poly shr (5 * (5-it))) and 31).toByte()
+ ((poly shr (5 * (5 - it))) and 31).toByte()
}.toByteArray()
}
/**
* Expands the human readable prefix per BIP173 for Checksum encoding
*/
- fun expandHrp(hrp: String) =
- hrp.map { c -> c.toInt() shr 5 }
+ private fun expandHrp(hrp: String) =
+ hrp.map { c -> c.code shr 5 }
.plus(0)
- .plus(hrp.map { c -> c.toInt() and 31 })
+ .plus(hrp.map { c -> c.code and 31 })
.toIntArray()
/**
@@ -243,9 +268,9 @@ class Bech32 {
*/
fun polymod(values: IntArray): Int {
var chk = 1
- return values.map {
- var b = chk shr 25
- chk = ((chk and 0x1ffffff) shl 5) xor it
+ return values.map { num ->
+ val b = chk shr 25
+ chk = ((chk and 0x1ffffff) shl 5) xor num
(0..4).map {
if (((b shr it) and 1) == 1) {
chk = chk xor gen[it]