vQyTPjcY

1package com.example.tp3_seg.entidades
2
3import android.annotation.TargetApi
4import android.os.Build
5import android.security.keystore.KeyGenParameterSpec
6import android.security.keystore.KeyProperties
7import android.util.Base64
8import androidx.annotation.RequiresApi
9import java.security.KeyStore
10import java.security.MessageDigest
11import javax.crypto.Cipher
12import javax.crypto.KeyGenerator
13import javax.crypto.SecretKey
14import javax.crypto.spec.IvParameterSpec
15
16class Criptografador {
17
18
19    val ks: KeyStore =
20        KeyStore.getInstance("AndroidKeyStore").apply { load(null) }
21
22    @RequiresApi(Build.VERSION_CODES.M)
23    fun getSecretKey(): SecretKey? {
24        var chave: SecretKey? = null
25        if(ks.containsAlias("chaveCripto")) {
26            val entrada = ks.getEntry("chaveCripto", null) as?
27                    KeyStore.SecretKeyEntry
28            chave = entrada?.secretKey
29        } else {
30            val builder = KeyGenParameterSpec.Builder("chaveCripto",
31                KeyProperties.PURPOSE_ENCRYPT or
32                        KeyProperties.PURPOSE_DECRYPT)
33            val keySpec = builder.setKeySize(256)
34                .setBlockModes(KeyProperties.BLOCK_MODE_CBC)
35                .setEncryptionPaddings(
36                    KeyProperties.ENCRYPTION_PADDING_PKCS7).build()
37            val kg = KeyGenerator.getInstance("AES", "AndroidKeyStore")
38            kg.init(keySpec)
39            chave = kg.generateKey()
40        }
41        return chave
42    }
43
44
45    @RequiresApi(Build.VERSION_CODES.M)
46    fun cipher(original: String): ByteArray {
47        var chave = getSecretKey()
48        return cipher(original,chave)
49    }
50
51    fun cipher(original: String, chave: SecretKey?): ByteArray {
52        if (chave != null) {
53            Cipher.getInstance("AES/CBC/PKCS7Padding").run {
54                init(Cipher.ENCRYPT_MODE,chave)
55                var valorCripto = doFinal(original.toByteArray())
56                var ivCripto = ByteArray(16)
57                iv.copyInto(ivCripto,0,0,16)
58                return ivCripto + valorCripto
59            }
60        } else return byteArrayOf()
61    }
62
63
64    @TargetApi(Build.VERSION_CODES.M)
65    fun decipher(cripto: ByteArray): String{
66        var chave = getSecretKey()
67        return decipher(cripto,chave)
68    }
69    fun decipher(cripto: ByteArray, chave: SecretKey?): String{
70        if (chave != null) {
71            Cipher.getInstance("AES/CBC/PKCS7Padding").run {
72                var ivCripto = ByteArray(16)
73                var valorCripto = ByteArray(cripto.size-16)
74                cripto.copyInto(ivCripto,0,0,16)
75                cripto.copyInto(valorCripto,0,16,cripto.size)
76                val ivParams = IvParameterSpec(ivCripto)
77                init(Cipher.DECRYPT_MODE,chave,ivParams)
78                return String(doFinal(valorCripto))
79            }
80        } else return ""
81    }
82
83    fun getHash(texto: String): String{
84        var md = MessageDigest.getInstance("MD5")
85        return Base64.encodeToString(
86            md.digest(texto.toByteArray()), Base64.DEFAULT).trimEnd()
87    }
88
89
90
91
92
93}