Remove apache library and manually convert ByteArray to Hex

    implementation 'androidx.recyclerview:recyclerview:1.0.0'

    implementation 'androidx.lifecycle:lifecycle-extensions:2.0.0'

    testImplementation 'junit:junit:4.12'

    implementation group: 'commons-codec', name: 'commons-codec', version: '1.11'

    implementation 'org.bouncycastle:bcprov-jdk15on:1.60'

    implementation 'org.bouncycastle:bcpg-jdk15on:1.60'

    implementation "androidx.vectordrawable:vectordrawable:1.0.0"

import android.content.Context

import android.os.AsyncTask

import foundation.e.apps.application.model.data.FullData

import org.apache.commons.codec.binary.Hex

import org.bouncycastle.jce.provider.BouncyCastleProvider

import org.bouncycastle.openpgp.PGPCompressedData

import org.bouncycastle.openpgp.PGPPublicKeyRingCollection

        integrityVerificationCallback.onIntegrityVerified(context, verificationSuccessful)

    }

    private fun getApkFileSha1(file: File): String {

    private fun getApkFileSha1(file: File): String?{

        val messageDigest = MessageDigest.getInstance("SHA-1")

        val fileInputStream = FileInputStream(file)

        var length = 0

                messageDigest.update(buffer, 0, length)

            }

        }

        return String(Hex.encodeHex(messageDigest.digest()))

        return byteArrayToHex(messageDigest.digest())

    }

    private fun byteArrayToHex(a: ByteArray): String? {

        val sb = StringBuilder(a.size * 2)

        for (b in a) sb.append(String.format("%02x", b))

        return sb.toString()

    }

    private fun verifyAPKSignature(