Kotlin is a powerful programming language that offers many features for developing secure applications. One of the most important security features is hashing. Hashing is a process of transforming data into a fixed-length value that is difficult to reverse. This makes it ideal for storing sensitive data such as passwords and for verifying the integrity of data.
Kotlin offers two hashing algorithms: PBKDF2 and bcrypt.
PBKDF2 is a standard algorithm for hashing passwords. It is specified in RFC 2898. PBKDF2 uses a pseudorandom function (PRF) and a salt to generate a hash. The PRF is a cryptographic function that takes a secret key and some input data and produces a pseudorandom output. PBKDF2 is computationally intensive, which makes it more resistant to brute-force attacks.
The following example shows how to hash a password using PBKDF2 in Kotlin:
import java.security.spec.KeySpec
import javax.crypto.SecretKeyFactory
import javax.crypto.spec.PBEKeySpec
fun main(args: Array<String>) {
// The password to hash
val password = "secret"
// The salt
val salt = byteArrayOf(0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f)
// The number of iterations
val iterations = 10000
// The size of the derived key in bits
val keySize = 256
try {
// Get the instance of the SecretKeyFactory
val keyFactory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1")
// Generate the key
val keySpec = PBEKeySpec(password.toCharArray(), salt, iterations, keySize)
val secretKey = keyFactory.generateSecret(keySpec)
// Get the key bytes
val keyBytes = secretKey.encoded
// Print the key
println(keyBytes.toHexString())
} catch (e: Exception) {
println(e)
}
}
bcrypt is a hashing algorithm designed for passwords. It is based on the Blowfish cipher and uses a salt to make the hashes more difficult to crack. bcrypt is more computationally intensive than PBKDF2, which makes it even more resistant to brute-force attacks.
The following example shows how to hash a password using bcrypt in Kotlin:
import org.mindrot.jbcrypt.BCrypt
fun main(args: Array<String>) {
// The password to hash
val password = "secret"
// The number of rounds
val rounds = 10
// The salt
val salt = BCrypt.gensalt(rounds)
// The hash
val hash = BCrypt.hashpw(password, salt)
// Print the hash
println(hash)
}