100 lines
3.3 KiB
Kotlin
100 lines
3.3 KiB
Kotlin
package com.lagradost.cloudstream3.extractors.helper
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import com.fasterxml.jackson.annotation.JsonProperty
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import com.lagradost.cloudstream3.base64DecodeArray
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import com.lagradost.cloudstream3.base64Encode
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import com.lagradost.cloudstream3.utils.AppUtils
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import java.security.DigestException
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import java.security.MessageDigest
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import javax.crypto.Cipher
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import javax.crypto.spec.IvParameterSpec
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import javax.crypto.spec.SecretKeySpec
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object AesHelper {
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private const val HASH = "AES/CBC/PKCS5PADDING"
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private const val KDF = "MD5"
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fun cryptoAESHandler(
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data: String,
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pass: ByteArray,
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encrypt: Boolean = true,
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padding: String = HASH,
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): String? {
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val parse = AppUtils.tryParseJson<AesData>(data) ?: return null
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val (key, iv) = generateKeyAndIv(
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pass,
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parse.s.hexToByteArray(),
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ivLength = parse.iv.length / 2,
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saltLength = parse.s.length / 2
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) ?: return null
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val cipher = Cipher.getInstance(padding)
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return if (!encrypt) {
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cipher.init(Cipher.DECRYPT_MODE, SecretKeySpec(key, "AES"), IvParameterSpec(iv))
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String(cipher.doFinal(base64DecodeArray(parse.ct)))
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} else {
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cipher.init(Cipher.ENCRYPT_MODE, SecretKeySpec(key, "AES"), IvParameterSpec(iv))
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base64Encode(cipher.doFinal(parse.ct.toByteArray()))
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}
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}
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// https://stackoverflow.com/a/41434590/8166854
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fun generateKeyAndIv(
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password: ByteArray,
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salt: ByteArray,
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hashAlgorithm: String = KDF,
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keyLength: Int = 32,
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ivLength: Int,
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saltLength: Int,
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iterations: Int = 1
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): Pair<ByteArray,ByteArray>? {
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val md = MessageDigest.getInstance(hashAlgorithm)
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val digestLength = md.digestLength
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val targetKeySize = keyLength + ivLength
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val requiredLength = (targetKeySize + digestLength - 1) / digestLength * digestLength
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val generatedData = ByteArray(requiredLength)
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var generatedLength = 0
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try {
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md.reset()
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while (generatedLength < targetKeySize) {
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if (generatedLength > 0)
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md.update(
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generatedData,
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generatedLength - digestLength,
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digestLength
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)
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md.update(password)
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md.update(salt, 0, saltLength)
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md.digest(generatedData, generatedLength, digestLength)
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for (i in 1 until iterations) {
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md.update(generatedData, generatedLength, digestLength)
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md.digest(generatedData, generatedLength, digestLength)
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}
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generatedLength += digestLength
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}
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return generatedData.copyOfRange(0, keyLength) to generatedData.copyOfRange(keyLength, targetKeySize)
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} catch (e: DigestException) {
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return null
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}
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}
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fun String.hexToByteArray(): ByteArray {
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check(length % 2 == 0) { "Must have an even length" }
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return chunked(2)
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.map { it.toInt(16).toByte() }
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.toByteArray()
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}
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private data class AesData(
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@JsonProperty("ct") val ct: String,
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@JsonProperty("iv") val iv: String,
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@JsonProperty("s") val s: String
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)
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} |