Hello guys, I need your help I'm building kmm appl...

# multiplatform

[Mod]

Hello guys,
I need your help
I'm building kmm application and part of the api call is md5 hash key, I made the implementation for android part but for iOS I couldn't use CryptoKit because it's pure swift and using the CoreCrypto I faced a lot of trouble converting the swift code to kotlin

this is the contract:

expect object EncryptionHelper {
    fun md5(input: String): String
}

this is the Android part:

import java.math.BigInteger
import java.security.MessageDigest

actual object EncryptionHelper {
    actual fun md5(input: String): String {
        val md = MessageDigest.getInstance("MD5")
        return BigInteger(1, md.digest(input.toByteArray())).toString(16).padStart(32, '0')
    }
}

[ephemient]

https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man3/CC_MD5.3cc.html

[ephemient]

in fact there is an example in this slack, https://kotlinlang.slack.com/archives/C3SGXARS6/p1544768698174600?thread_ts=1541771174.265700&cid=C3SGXARS6 (although .toString(16) looks suspiciously wrong to me… you'd need to .padStart(2, '0') or change how the string representation is generated)

[ephemient]

replacing CC_SHA256 with CC_MD5 of course, but it works the same way

[Mod]

thank you, I will check this

[ephemient]

I'd probably do

fun UByteArray.toHexString(): String = buildString(size * 2) {
    for (ubyte in this@toHexString) {
        append((ubyte.toInt() shr 4 and 15).digitToChar(radix = 16))
        append((ubyte.toInt() and 15).digitToChar(radix = 16))
    }
}

[Mod]

perfect, I need it in hex string

[jessewilson]

MIGHT consider Okio’s ByteString, which implements md5 and hex in multiplatform code

[Mod]

Thank you, I will check this