CodeChallenge.kt
/*
* Copyright 2021 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.wear.phone.interactions.authentication
import android.os.Build
import androidx.annotation.RequiresApi
import java.nio.charset.StandardCharsets
import java.security.MessageDigest
import java.util.Base64
/**
* Authorization code challenge
*
* * Related specifications:
* Proof Key for Code Exchange by OAuth Public Clients (RFC 7636).
* https://tools.ietf.org/html/rfc7636
*/
@RequiresApi(Build.VERSION_CODES.O)
public class CodeChallenge constructor(
codeVerifier: CodeVerifier
) {
/**
* The challenge value.
*/
private var value: String? = null
/**
* Computes the code challenge value using the specified verifier with SHA-256.
*/
init {
val md = MessageDigest.getInstance("SHA-256")
val hash: ByteArray = md.digest(codeVerifier.getValueBytes())
value = Base64.getUrlEncoder().withoutPadding().encodeToString(hash)
}
public fun getValue(): String {
return value!!
}
override fun equals(other: Any?): Boolean {
if (other is CodeChallenge) {
return other.getValue() == value
}
return false
}
override fun hashCode(): Int {
return value!!.toByteArray(StandardCharsets.UTF_8).contentHashCode()
}
}