[Android] Kotlin- Encode Base64 & Encrypt SHA-512

1. Encode Base64 

- Base64.NO_WRAP : Base64 값의 마지막에 붙는 '\n'를 삭제

val target = "TEXT"
val base64 = Base64.encodeToString(target.toByteArray(StandardCharsets.UTF_8), Base64.NO_WRAP)

2. Encrypt SHA-512

- MessageDigest algorighm으로 MD5, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512 사용 가능

fun getEncrypt() : String{
   val target = "TEXT"
   val messageDigest = MessageDigest.getInstance("SHA-512")
   val digest = md.digest(target .toByteArray())
   val encryptedStr = StringBuilder()
   for (i in digest.indices) {
      sb.append(Integer.toString((digest[i] and 0xff.toByte()) + 0x100, 16).substring(1))
   }

   return encryptedStr 
}