refactor: Change PBKDF2SHA512 from class to Object

apollo/src/androidMain/kotlin/io/iohk/atala/prism/apollo/hashing/PBKDF2SHA512.kt

@@ -7,24 +7,22 @@ import org.bitcoinj.crypto.PBKDF2SHA512
  * deriving a key from a password using the PBKDF2 algorithm with SHA-512
  * hash function.
  */
-actual class PBKDF2SHA512 {
-    actual companion object {
-        /**
-         * Derives a key from a password using the PBKDF2 algorithm with SHA-512 hash function.
-         *
-         * @param p The password used for key derivation.
-         * @param s The salt value.
-         * @param c The iteration count.
-         * @param dkLen The desired length of the derived key in bytes.
-         * @return The derived key as a ByteArray.
-         */
-        actual fun derive(
-            p: String,
-            s: String,
-            c: Int,
-            dkLen: Int
-        ): ByteArray {
-            return PBKDF2SHA512.derive(p, s, c, dkLen)
-        }
+actual object PBKDF2SHA512 {
+    /**
+     * Derives a key from a password using the PBKDF2 algorithm with SHA-512 hash function.
+     *
+     * @param p The password used for key derivation.
+     * @param s The salt value.
+     * @param c The iteration count.
+     * @param dkLen The desired length of the derived key in bytes.
+     * @return The derived key as a ByteArray.
+     */
+    actual fun derive(
+        p: String,
+        s: String,
+        c: Int,
+        dkLen: Int
+    ): ByteArray {
+        return PBKDF2SHA512.derive(p, s, c, dkLen)
     }
 }

apollo/src/appleMain/kotlin/io/iohk/atala/prism/apollo/hashing/PBKDF2SHA512.kt

@@ -13,50 +13,48 @@ import platform.CoreCrypto.kCCPRFHmacAlgSHA512
  * deriving a key from a password using the PBKDF2 algorithm with SHA-512
  * hash function.
  */
-actual class PBKDF2SHA512 {
-    actual companion object {
-        /**
-         * Derives a key from a password using the PBKDF2 algorithm with SHA-512 hash function.
-         *
-         * @param p The password used for key derivation.
-         * @param s The salt value.
-         * @param c The iteration count.
-         * @param dkLen The desired length of the derived key in bytes.
-         * @return The derived key as a ByteArray.
-         */
-        @OptIn(ExperimentalUnsignedTypes::class, ExperimentalForeignApi::class)
-        actual fun derive(
-            p: String,
-            s: String,
-            c: Int,
-            dkLen: Int
-        ): ByteArray {
-            val rounds = c.toUInt()
-            val salt = s.encodeToByteArray().toUByteArray()
-            val derivedKey = UByteArray(dkLen) // initialize buffer for derived key
+actual object PBKDF2SHA512 {
+    /**
+     * Derives a key from a password using the PBKDF2 algorithm with SHA-512 hash function.
+     *
+     * @param p The password used for key derivation.
+     * @param s The salt value.
+     * @param c The iteration count.
+     * @param dkLen The desired length of the derived key in bytes.
+     * @return The derived key as a ByteArray.
+     */
+    @OptIn(ExperimentalUnsignedTypes::class, ExperimentalForeignApi::class)
+    actual fun derive(
+        p: String,
+        s: String,
+        c: Int,
+        dkLen: Int
+    ): ByteArray {
+        val rounds = c.toUInt()
+        val salt = s.encodeToByteArray().toUByteArray()
+        val derivedKey = UByteArray(dkLen) // initialize buffer for derived key
 
-            derivedKey.usePinned { derivedKeyPin ->
-                salt.usePinned { saltPin ->
+        derivedKey.usePinned { derivedKeyPin ->
+            salt.usePinned { saltPin ->
 
-                    val result = CCKeyDerivationPBKDF(
-                        algorithm = kCCPBKDF2,
-                        password = p,
-                        passwordLen = p.length.convert(),
-                        salt = saltPin.addressOf(0),
-                        saltLen = saltPin.get().size.convert(),
-                        prf = kCCPRFHmacAlgSHA512,
-                        rounds = rounds,
-                        derivedKey = derivedKeyPin.addressOf(0),
-                        derivedKeyLen = derivedKeyPin.get().size.convert()
-                    )
+                val result = CCKeyDerivationPBKDF(
+                    algorithm = kCCPBKDF2,
+                    password = p,
+                    passwordLen = p.length.convert(),
+                    salt = saltPin.addressOf(0),
+                    saltLen = saltPin.get().size.convert(),
+                    prf = kCCPRFHmacAlgSHA512,
+                    rounds = rounds,
+                    derivedKey = derivedKeyPin.addressOf(0),
+                    derivedKeyLen = derivedKeyPin.get().size.convert()
+                )
 
-                    if (result != 0) {
-                        throw Error("Key derivation failed with error: $result")
-                    }
+                if (result != 0) {
+                    throw Error("Key derivation failed with error: $result")
                 }
             }
-
-            return derivedKey.toByteArray()
         }
+
+        return derivedKey.toByteArray()
     }
 }

apollo/src/commonMain/kotlin/io/iohk/atala/prism/apollo/hashing/PBKDF2SHA512.kt

@@ -5,17 +5,15 @@ package io.iohk.atala.prism.apollo.hashing
  * deriving a key from a password using the PBKDF2 algorithm with SHA-512
  * hash function.
  */
-expect class PBKDF2SHA512 {
-    companion object {
-        /**
-         * Derives a key from a password using the PBKDF2 algorithm with SHA-512 hash function.
-         *
-         * @param p The password used for key derivation.
-         * @param s The salt value.
-         * @param c The iteration count.
-         * @param dkLen The desired length of the derived key in bytes.
-         * @return The derived key as a ByteArray.
-         */
-        fun derive(p: String, s: String, c: Int, dkLen: Int): ByteArray
-    }
+expect object PBKDF2SHA512 {
+    /**
+     * Derives a key from a password using the PBKDF2 algorithm with SHA-512 hash function.
+     *
+     * @param p The password used for key derivation.
+     * @param s The salt value.
+     * @param c The iteration count.
+     * @param dkLen The desired length of the derived key in bytes.
+     * @return The derived key as a ByteArray.
+     */
+    fun derive(p: String, s: String, c: Int, dkLen: Int): ByteArray
 }

apollo/src/jsMain/kotlin/io/iohk/atala/prism/apollo/hashing/PBKDF2SHA512.kt

@@ -10,33 +10,31 @@ import org.khronos.webgl.get
  * deriving a key from a password using the PBKDF2 algorithm with SHA-512
  * hash function.
  */
-actual class PBKDF2SHA512 {
-    actual companion object {
-        /**
-         * Derives a key from a password using the PBKDF2 algorithm with SHA-512 hash function.
-         *
-         * @param p The password used for key derivation.
-         * @param s The salt value.
-         * @param c The iteration count.
-         * @param dkLen The desired length of the derived key in bytes.
-         * @return The derived key as a ByteArray.
-         */
-        actual fun derive(
-            p: String,
-            s: String,
-            c: Int,
-            dkLen: Int
-        ): ByteArray {
-            val opts = js("{}")
-            opts.c = 2048
-            opts.dkLen = 64
-            val derived = pbkdf2(sha512, p, s, opts).buffer
-            val uint8Array = Uint8Array(derived)
-            val byteArray = ByteArray(uint8Array.length)
-            for (i in 0 until uint8Array.length) {
-                byteArray[i] = uint8Array[i].toByte()
-            }
-            return byteArray
+actual object PBKDF2SHA512 {
+    /**
+     * Derives a key from a password using the PBKDF2 algorithm with SHA-512 hash function.
+     *
+     * @param p The password used for key derivation.
+     * @param s The salt value.
+     * @param c The iteration count.
+     * @param dkLen The desired length of the derived key in bytes.
+     * @return The derived key as a ByteArray.
+     */
+    actual fun derive(
+        p: String,
+        s: String,
+        c: Int,
+        dkLen: Int
+    ): ByteArray {
+        val opts = js("{}")
+        opts.c = 2048
+        opts.dkLen = 64
+        val derived = pbkdf2(sha512, p, s, opts).buffer
+        val uint8Array = Uint8Array(derived)
+        val byteArray = ByteArray(uint8Array.length)
+        for (i in 0 until uint8Array.length) {
+            byteArray[i] = uint8Array[i].toByte()
         }
+        return byteArray
     }
 }

apollo/src/jvmMain/kotlin/io/iohk/atala/prism/apollo/hashing/PBKDF2SHA512.kt

@@ -7,24 +7,22 @@ import org.bitcoinj.crypto.PBKDF2SHA512
  * deriving a key from a password using the PBKDF2 algorithm with SHA-512
  * hash function.
  */
-actual class PBKDF2SHA512 {
-    actual companion object {
-        /**
-         * Derives a key from a password using the PBKDF2 algorithm with SHA-512 hash function.
-         *
-         * @param p The password used for key derivation.
-         * @param s The salt value.
-         * @param c The iteration count.
-         * @param dkLen The desired length of the derived key in bytes.
-         * @return The derived key as a ByteArray.
-         */
-        actual fun derive(
-            p: String,
-            s: String,
-            c: Int,
-            dkLen: Int
-        ): ByteArray {
-            return PBKDF2SHA512.derive(p, s, c, dkLen)
-        }
+actual object PBKDF2SHA512 {
+    /**
+     * Derives a key from a password using the PBKDF2 algorithm with SHA-512 hash function.
+     *
+     * @param p The password used for key derivation.
+     * @param s The salt value.
+     * @param c The iteration count.
+     * @param dkLen The desired length of the derived key in bytes.
+     * @return The derived key as a ByteArray.
+     */
+    actual fun derive(
+        p: String,
+        s: String,
+        c: Int,
+        dkLen: Int
+    ): ByteArray {
+        return PBKDF2SHA512.derive(p, s, c, dkLen)
     }
 }