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-rw-r--r--taler-kotlin-android/src/main/java/net/taler/common/Amount.kt11
-rw-r--r--taler-kotlin-android/src/main/java/net/taler/common/Bech32.kt257
-rw-r--r--taler-kotlin-android/src/main/java/net/taler/common/CyptoUtils.kt71
3 files changed, 339 insertions, 0 deletions
diff --git a/taler-kotlin-android/src/main/java/net/taler/common/Amount.kt b/taler-kotlin-android/src/main/java/net/taler/common/Amount.kt
index a36c0ab..18fb6cb 100644
--- a/taler-kotlin-android/src/main/java/net/taler/common/Amount.kt
+++ b/taler-kotlin-android/src/main/java/net/taler/common/Amount.kt
@@ -56,12 +56,19 @@ public data class Amount(
public companion object {
private const val FRACTIONAL_BASE: Int = 100000000 // 1e8
+ public val SEGWIT_MIN = Amount("BTC", 0, 294)
private val REGEX_CURRENCY = Regex("""^[-_*A-Za-z0-9]{1,12}$""")
public val MAX_VALUE: Long = 2.0.pow(52).toLong()
private const val MAX_FRACTION_LENGTH = 8
public const val MAX_FRACTION: Int = 99_999_999
+ public fun fromDouble(currency: String, value: Double): Amount {
+ val intPart = Math.floor(value).toLong()
+ val fraPart = Math.floor((value - intPart) * FRACTIONAL_BASE).toInt()
+ return Amount(currency, intPart, fraPart)
+ }
+
public fun zero(currency: String): Amount {
return Amount(checkCurrency(currency), 0, 0)
}
@@ -141,6 +148,10 @@ public data class Amount(
return result
}
+ public fun withCurrency(currency: String): Amount {
+ return Amount(checkCurrency(currency), this.value, this.fraction)
+ }
+
public operator fun minus(other: Amount): Amount {
check(currency == other.currency) { "Can only subtract from same currency" }
var resultValue = value
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
new file mode 100644
index 0000000..32885df
--- /dev/null
+++ b/taler-kotlin-android/src/main/java/net/taler/common/Bech32.kt
@@ -0,0 +1,257 @@
+/*
+ * This file is part of GNU Taler
+ * (C) 2020 Taler Systems S.A.
+ *
+ * GNU Taler is free software; you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation; either version 3, or (at your option) any later version.
+ *
+ * GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ * A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ * 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.
+
+// Copyright (c) 2017 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+// modified version of https://gist.github.com/iramiller/4ebfcdfbc332a9722c4a4abeb4e16454
+
+import net.taler.common.CyptoUtils
+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) {
+
+ /**
+ * The encapsulated data as typical 8bit bytes.
+ */
+ val data = Bech32.convertBits(fiveBitData, 5, 8, false)
+
+ /**
+ * Address is the Bech32 encoded value of the data prefixed with the human readable portion and
+ * protected by an appended checksum.
+ */
+ val address = Bech32.encode(hrp, fiveBitData)
+
+ /**
+ * Checksum for encapsulated data + hrp
+ */
+ val checksum = Bech32.checksum(this.hrp, this.fiveBitData.toTypedArray())
+
+ /**
+ * The Bech32 Address toString prints state information for debugging purposes.
+ * @see address() for the bech32 encoded address string output.
+ */
+ override fun toString(): String {
+ return "bech32 : ${this.address}\nhuman: ${this.hrp} \nbytes"
+ }
+}
+
+/**
+ * BIP173 compliant processing functions for handling Bech32 encoding for addresses
+ */
+class Bech32 {
+
+ companion object {
+ const val CHECKSUM_SIZE = 6
+ const val MIN_VALID_LENGTH = 8
+ const val MAX_VALID_LENGTH = 90
+ const val MIN_VALID_CODEPOINT = 33
+ const val MAX_VALID_CODEPOINT = 126
+
+ const val charset = "qpzry9x8gf2tvdw0s3jn54khce6mua7l"
+ val gen = intArrayOf(0x3b6a57b2, 0x26508e6d, 0x1ea119fa, 0x3d4233dd, 0x2a1462b3)
+
+ fun generateFakeSegwitAddress(reservePub: String?, addr: String): List<String> {
+ if (reservePub == null || reservePub.isEmpty()) return listOf<String>()
+ 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)
+
+ first_rnd[0] = first_rnd[0].and(0b0111_1111);
+ second_rnd[0] = second_rnd[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 second_part = ByteArray(20);
+ second_rnd.copyInto( second_part, 0, 0, 4)
+ pub.copyInto( second_part, 4, 16, 32)
+
+ val zero = ByteArray(1)
+ zero[0] = 0
+ val hrp = when {
+ addr[0] == 'b' && addr[1] == 'c' && addr[2] == 'r' && addr[3] == 't' -> "bcrt"
+ addr[0] == 't' && addr[1] == 'b' -> "tb"
+ addr[0] == 'b' && addr[1] == 'c' -> "bc"
+ else -> throw Error("unknown bitcoin net")
+ }
+
+ return listOf(
+ Bech32Data(hrp, zero + convertBits(first_part, 8, 5, true)).address,
+ Bech32Data(hrp, zero + convertBits(second_part, 8, 5, true)).address,
+ )
+ }
+
+ /**
+ * 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.equals(bech32.toLowerCase()) || bech32.equals(bech32.toUpperCase()))
+ { "bech32 must be either all upper or lower case" }
+ 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()
+
+ 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 actualSum = checksum(hrp, dataBytes.dropLast(CHECKSUM_SIZE).toTypedArray())
+ require(1 == polymod(expandHrp(hrp).plus(dataBytes.map { d -> d.toInt() }))) { "checksum failed: $checkBytes != $actualSum" }
+
+ return Bech32Data(hrp, dataBytes.dropLast(CHECKSUM_SIZE).toByteArray())
+ }
+
+ /**
+ * ConvertBits regroups bytes with toBits set based on reading groups of bits as a continuous stream group by fromBits.
+ * 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"}
+
+ // resulting bytes with each containing the toBits bits from the input set.
+ var regrouped = arrayListOf<Byte>()
+
+ var nextByte = 0.toUByte()
+ var filledBits = 0
+
+ data.forEach { d ->
+ // discard unused bits.
+ var b = (d.toUByte() shl (8 - fromBits))
+
+ // How many bits remain to extract from input data.
+ var remainFromBits = fromBits
+
+ while (remainFromBits > 0) {
+ // How many bits remain to be copied in
+ 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"}
+
+ // 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))
+
+ // discard extracted bits and update position counters
+ b = b shl toExtract
+ remainFromBits -= toExtract
+ filledBits += toExtract
+
+ // if we have a complete group then reset.
+ if (filledBits == toBits) {
+ regrouped.add(nextByte.toByte())
+ filledBits = 0
+ nextByte = 0.toUByte()
+ }
+ }
+ }
+
+ // pad any unfinished groups as required
+ if (pad && filledBits > 0) {
+ nextByte = nextByte shl (toBits - filledBits)
+ regrouped.add(nextByte.toByte())
+ filledBits = 0
+ nextByte = 0.toUByte()
+ }
+
+ return regrouped.toByteArray()
+ }
+
+ /**
+ * Encodes data 5-bit bytes (data) with a given human readable portion (hrp) into a bech32 string.
+ * @see convertBits for conversion or ideally use the Bech32Data extension functions
+ */
+ fun encode(hrp: String, fiveBitData: ByteArray): String {
+ return (fiveBitData.plus(checksum(hrp, fiveBitData.toTypedArray()))
+ .map { b -> charset[b.toInt()] }).joinToString("", hrp + "1")
+ }
+
+ /**
+ * Calculates a bech32 checksum based on BIP 173 specification
+ */
+ fun checksum(hrp: String, data: Array<Byte>): ByteArray {
+ var values = expandHrp(hrp)
+ .plus(data.map { d -> d.toInt() })
+ .plus(Array<Int>(6){ _ -> 0}.toIntArray())
+
+ var poly = polymod(values) xor 1
+
+ return (0..5).map {
+ ((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 }
+ .plus(0)
+ .plus(hrp.map { c -> c.toInt() and 31 })
+ .toIntArray()
+
+ /**
+ * Polynomial division function for checksum calculation. For details see BIP173
+ */
+ fun polymod(values: IntArray): Int {
+ var chk = 1
+ return values.map {
+ var b = chk shr 25
+ chk = ((chk and 0x1ffffff) shl 5) xor it
+ (0..4).map {
+ if (((b shr it) and 1) == 1) {
+ chk = chk xor gen[it]
+ }
+ }
+ }.let { chk }
+ }
+ }
+} \ No newline at end of file
diff --git a/taler-kotlin-android/src/main/java/net/taler/common/CyptoUtils.kt b/taler-kotlin-android/src/main/java/net/taler/common/CyptoUtils.kt
new file mode 100644
index 0000000..c1fbe8c
--- /dev/null
+++ b/taler-kotlin-android/src/main/java/net/taler/common/CyptoUtils.kt
@@ -0,0 +1,71 @@
+/*
+ * This file is part of GNU Taler
+ * (C) 2022 Taler Systems S.A.
+ *
+ * GNU Taler is free software; you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation; either version 3, or (at your option) any later version.
+ *
+ * GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ * A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ * 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/>
+ */
+
+package net.taler.common
+
+import kotlin.math.floor
+
+object CyptoUtils {
+ internal fun getValue(c: Char): Int {
+ val a = when (c) {
+ 'o','O' -> '0'
+ 'i','I','l','L' -> '1'
+ 'u','U' -> 'V'
+ else -> c
+ }
+ if (a in '0'..'9') {
+ return a - '0'
+ }
+ val A = if (a in 'a'..'z') a.uppercaseChar() else a
+ var dec = 0
+ if (A in 'A'..'Z') {
+ if ('I' < A) dec++
+ if ('L' < A) dec++
+ if ('O' < A) dec++
+ if ('U' < A) dec++
+ return A - 'A' + 10 - dec
+ }
+ throw Error("encoding error")
+ }
+
+ fun decodeCrock(e: String): ByteArray {
+ val size = e.length
+ var bitpos = 0
+ var bitbuf = 0
+ var readPosition = 0
+ val outLen = floor((size * 5f) / 8).toInt()
+ val out = ByteArray(outLen)
+ var outPos = 0
+ while (readPosition < size || bitpos > 0) {
+ if (readPosition < size) {
+ val v = getValue(e[readPosition++])
+ bitbuf = bitbuf.shl(5).or(v)
+ bitpos += 5
+ }
+ while (bitpos >= 8) {
+ val d = bitbuf.shr(bitpos -8).and(0xff).toByte()
+ out[outPos++] = d
+ bitpos -= 8
+ }
+ if (readPosition == size && bitpos > 0) {
+ bitbuf = bitbuf.shl( 8 - bitpos).and(0xff)
+ bitpos = if (bitbuf == 0) 0 else 8
+ }
+ }
+ return out
+ }
+
+} \ No newline at end of file