Bitcoin/address validation: Difference between revisions

=={{header|Kotlin}}==

{{trans|Java}}

<lang scala>// version 1.0.6

import java.security.MessageDigest

object Bitcoin {

private const val ALPHABET = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"

private fun ByteArray.contentEquals(other: ByteArray): Boolean {

if (this.size != other.size) return false

for (i in 0 until this.size) if (this[i] != other[i]) return false

return true

}

private fun decodeBase58(input: String): ByteArray? {

val output = ByteArray(25)

for (c in input) {

var p = ALPHABET.indexOf(c)

if (p == -1) return null

for (j in 24 downTo 1) {

p += 58 * (output[j].toInt() and 0xff)

output[j] = (p % 256).toByte()

p = p shr 8

}

if (p != 0) return null

}

return output

}

private fun sha256(data: ByteArray, start: Int, len: Int, recursion: Int): ByteArray {

if (recursion == 0) return data

val md = MessageDigest.getInstance("SHA-256")

md.update(data.sliceArray(start until start + len))

return sha256(md.digest(), 0, 32, recursion - 1)

}

fun validateAddress(address: String): Boolean {

if (address.length !in 26..35) return false

val decoded = decodeBase58(address)

if (decoded == null) return false

val hash = sha256(decoded, 0, 21, 2)

return hash.sliceArray(0..3).contentEquals(decoded.sliceArray(21..24))

}

}

fun main(args: Array<String>) {

val addresses = arrayOf(

"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",

"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j",

"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9",

"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X",

"1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",

"1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",

"BZbvjr",

"i55j",

"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62!",

"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62iz",

"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62izz",

"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9",

"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I"

)

for (address in addresses)

println("${address.padEnd(36)} -> ${if (Bitcoin.validateAddress(address)) "valid" else "invalid"}")

}</lang>

{{out}}

<pre>

1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i -> valid

1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j -> invalid

1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9 -> valid

1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X -> invalid

1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i -> invalid

1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i -> invalid

BZbvjr -> invalid

i55j -> invalid

1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62! -> invalid

1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62iz -> invalid

1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62izz -> invalid

1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9 -> invalid

1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I -> invalid

</pre>