docs: add comments to code

apollo/src/commonMain/kotlin/io/iohk/atala/prism/apollo/derivation/HDKey.kt

@@ -182,6 +182,11 @@ class HDKey(
         return this.deriveChild(BigIntegerWrapper(BigInteger(index)))
     }
 
+    /**
+     * Method to get the KMMECSecp256k1PrivateKey from HDKey
+     *
+     * @return KMMECSecp256k1PrivateKey
+     */
     fun getKMMSecp256k1PrivateKey(): KMMECSecp256k1PrivateKey {
         privateKey?.let {
             return KMMECSecp256k1PrivateKey.secp256k1FromByteArray(privateKey)

apollo/src/commonMain/kotlin/io/iohk/atala/prism/apollo/derivation/MnemonicHelper.kt

@@ -4,6 +4,9 @@ import io.iohk.atala.prism.apollo.hashing.PBKDF2SHA512
 import io.iohk.atala.prism.apollo.securerandom.SecureRandom
 import org.kotlincrypto.hash.sha2.SHA256
 
+/**
+ * This helper provides a set of methods to work with Mnemonics
+ */
 final class MnemonicHelper {
     companion object {
         private const val SEED_ENTROPY_BITS_24_WORDS = 256
@@ -13,15 +16,33 @@ final class MnemonicHelper {
 
         class InvalidMnemonicCode(code: String) : RuntimeException(code)
 
+        /**
+         * It validates if a provided list of works is a valid mnemonic
+         *
+         * @return Boolean
+         */
         fun isValidMnemonicCode(code: List<String>): Boolean {
             return code.all { it in MnemonicCodeEnglish.wordList }
         }
 
+        /**
+         * It creates a random list of works
+         *
+         * @return List<String> as mnemonics
+         */
         fun createRandomMnemonics(): List<String> {
             val entropyBytes = SecureRandom.generateSeed(SEED_ENTROPY_BITS_24_WORDS / 8)
             return toMnemonicCode(MnemonicCodeEnglish.wordList, entropyBytes)
         }
 
+        /**
+         * Creates a seed from a mnemonics list and a passphrase.
+         *
+         * @param mnemonics The word list used for generating the mnemonic code.
+         * @param passphrase Passphrase used to derive the mnemonic string
+         * @throws InvalidMnemonicCode if the list of mnemonics is invalid
+         * @return ByteArray representing the seed raw value
+         */
         @Throws(InvalidMnemonicCode::class)
         fun createSeed(mnemonics: List<String>, passphrase: String = "AtalaPrism"): ByteArray {
             if (!isValidMnemonicCode(mnemonics)) {
@@ -36,11 +57,25 @@ final class MnemonicHelper {
             )
         }
 
+        /**
+         * Create random seed with a passphrase
+         *
+         * @param String passphrase to include into the seed creation
+         * @return ByteArray seed raw value
+         */
         fun createRandomSeed(passphrase: String = "AtalaPrism"): ByteArray {
             val mnemonics = this.createRandomMnemonics()
             return this.createSeed(mnemonics, passphrase)
         }
 
+        /**
+         * Converts a byte array of entropy into a mnemonic code (word list) based on the specified word list.
+         *
+         * @param words The word list to be used for generating the mnemonic code. This list should conform to the BIP-39 standard.
+         * @param entropy The entropy byte array, which is used to generate the mnemonic code. The length of this array must be a multiple of 4 bytes (32 bits).
+         * @throws Exception if the entropy is empty or its length is not a multiple of 32 bits.
+         * @return A list of strings representing the mnemonic code.
+         */
         fun toMnemonicCode(words: List<String>, entropy: ByteArray): List<String> {
             if (entropy.size % 4 > 0) {
                 throw Exception("Entropy length not multiple of 32 bits.")

apollo/src/commonMain/kotlin/io/iohk/atala/prism/apollo/secp256k1/Secp256k1Lib.kt

@@ -1,15 +1,60 @@
 package io.iohk.atala.prism.apollo.secp256k1
 
+/**
+ * This class provides various Secp256k1 cryptographic functionalities such as creating public keys, signing data,
+ * verifying signatures, and compressing or decompressing public keys.
+ */
 expect class Secp256k1Lib constructor() {
+    /**
+     * Creates a public key from a given private key.
+     *
+     * @param privateKey The private key in byte array format.
+     * @param compressed A boolean indicating whether the public key should be compressed.
+     * @return A byte array representing the public key.
+     */
     fun createPublicKey(privateKey: ByteArray, compressed: Boolean): ByteArray
 
+    /**
+     * Derives a new private key from an existing private key and derived bytes.
+     *
+     * @param privateKeyBytes The original private key in byte array format.
+     * @param derivedPrivateKeyBytes The byte array used for deriving the new private key.
+     * @return A byte array representing the derived private key, or null if derivation fails.
+     */
     fun derivePrivateKey(privateKeyBytes: ByteArray, derivedPrivateKeyBytes: ByteArray): ByteArray?
 
+    /**
+     * Signs data using a given private key.
+     *
+     * @param privateKey The private key used for signing, in byte array format.
+     * @param data The data to be signed, in byte array format.
+     * @return A byte array representing the signature.
+     */
     fun sign(privateKey: ByteArray, data: ByteArray): ByteArray
 
+    /**
+     * Verifies a signature against a public key and data.
+     *
+     * @param publicKey The public key in byte array format.
+     * @param signature The signature to be verified, in byte array format.
+     * @param data The data against which the signature will be verified, in byte array format.
+     * @return A boolean indicating whether the signature is valid.
+     */
     fun verify(publicKey: ByteArray, signature: ByteArray, data: ByteArray): Boolean
 
+    /**
+     * Decompresses a compressed public key.
+     *
+     * @param compressed The compressed public key in byte array format.
+     * @return A byte array representing the uncompressed public key.
+     */
     fun uncompressPublicKey(compressed: ByteArray): ByteArray
 
+    /**
+     * Compresses an uncompressed public key.
+     *
+     * @param uncompressed The uncompressed public key in byte array format.
+     * @return A byte array representing the compressed public key.
+     */
     fun compressPublicKey(uncompressed: ByteArray): ByteArray
 }

apollo/src/commonMain/kotlin/io/iohk/atala/prism/apollo/utils/Ed25519KeyPairGeneration.kt

@@ -3,8 +3,17 @@ package io.iohk.atala.prism.apollo.utils
 import kotlin.js.ExperimentalJsExport
 import kotlin.js.JsExport
 
+/**
+ * Interface defining the functionality for generating Ed25519 key pairs.
+ */
 @ExperimentalJsExport
 @JsExport
 interface Ed25519KeyPairGeneration {
+
+    /**
+     * Generates an Ed25519 key pair.
+     *
+     * @return A [KMMEdKeyPair] instance representing the generated public and private keys.
+     */
     fun generateKeyPair(): KMMEdKeyPair
 }

apollo/src/commonMain/kotlin/io/iohk/atala/prism/apollo/utils/KMMECPoint.kt

@@ -3,6 +3,9 @@ package io.iohk.atala.prism.apollo.utils
 import kotlin.js.ExperimentalJsExport
 import kotlin.js.JsExport
 
+/**
+ * Representation of an EC curve point
+ */
 @OptIn(ExperimentalJsExport::class)
 @JsExport
 data class KMMECPoint(val x: ByteArray, val y: ByteArray) {

apollo/src/commonMain/kotlin/io/iohk/atala/prism/apollo/utils/KMMECSecp256k1PrivateKey.kt

@@ -23,6 +23,9 @@ interface KMMECSecp256k1PrivateKeyCommonStaticInterface {
     }
 }
 
+/**
+ * Definition of the KMMECSecp256k1PublicKey functionality
+ */
 @OptIn(ExperimentalJsExport::class)
 @JsExport
 class KMMECSecp256k1PrivateKey : Encodable {
@@ -33,11 +36,21 @@ class KMMECSecp256k1PrivateKey : Encodable {
         this.raw = raw
     }
 
+    /**
+     * Method to fetch the KMMECSecp256k1PublicKey
+     *
+     * @return KMMECSecp256k1PublicKey
+     */
     fun getPublicKey(): KMMECSecp256k1PublicKey {
         val pubKeyBytes = Secp256k1Lib().createPublicKey(raw, false)
         return KMMECSecp256k1PublicKey(pubKeyBytes)
     }
 
+    /**
+     * Method to get the encoded raw value
+     *
+     * @return ByteArray representing the raw value of this KMMECSecp256k1PrivateKey
+     */
     override fun getEncoded(): ByteArray {
         return raw
     }

apollo/src/commonMain/kotlin/io/iohk/atala/prism/apollo/utils/KMMECSecp256k1PublicKey.kt

@@ -54,6 +54,9 @@ interface KMMECSecp256k1PublicKeyCommonStaticInterface {
     }
 }
 
+/**
+ * Definition of the KMMECSecp256k1PublicKey functionality
+ */
 @OptIn(ExperimentalJsExport::class)
 @JsExport
 class KMMECSecp256k1PublicKey {
@@ -64,6 +67,11 @@ class KMMECSecp256k1PublicKey {
         this.raw = raw
     }
 
+    /**
+     * Method to get the CurvePoint of KMMECSecp256k1PublicKey
+     *
+     * @return KMMECPoint
+     */
     fun getCurvePoint(): KMMECPoint {
         if (raw.size != 65) {
             throw IllegalArgumentException("Public key should be 65 bytes long")

apollo/src/commonMain/kotlin/io/iohk/atala/prism/apollo/utils/KMMEdKeyPair.kt

@@ -2,14 +2,30 @@ package io.iohk.atala.prism.apollo.utils
 
 import kotlin.js.ExperimentalJsExport
 
+/**
+ * Interface defining the functionality for generating KMMEd key pairs.
+ */
 @ExperimentalJsExport
 expect class KMMEdKeyPair(privateKey: KMMEdPrivateKey, publicKey: KMMEdPublicKey) {
     val privateKey: KMMEdPrivateKey
     val publicKey: KMMEdPublicKey
 
     companion object : Ed25519KeyPairGeneration
 
+    /**
+     * Method to sign a provided message
+     *
+     * @param message A ByteArray with the message to be signed
+     * @return A ByteArray conforming the signed message
+     */
     fun sign(message: ByteArray): ByteArray
 
+    /**
+     * Method to verify a provided message and signature
+     *
+     * @param message A ByteArray with the original message
+     * @param sig The signature to be verified
+     * @return A boolean that tell us if the signature matches the original message
+     */
     fun verify(message: ByteArray, sig: ByteArray): Boolean
 }

apollo/src/commonMain/kotlin/io/iohk/atala/prism/apollo/utils/KMMEdPrivateKey.kt

@@ -1,5 +1,15 @@
 package io.iohk.atala.prism.apollo.utils
 
+/**
+ * Definition of the KMMEdPrivateKey functionality
+ */
 public expect class KMMEdPrivateKey {
+
+    /**
+     * Method to sign a message using this KMMEdPrivateKey
+     *
+     * @param message ByteArray representing the message to be signed
+     * @return ByteArray representing the signed message
+     */
     fun sign(message: ByteArray): ByteArray
 }

apollo/src/commonMain/kotlin/io/iohk/atala/prism/apollo/utils/KMMEdPublicKey.kt

@@ -1,5 +1,16 @@
 package io.iohk.atala.prism.apollo.utils
 
+/**
+ * Definition of the KMMEdPublicKey functionality
+ */
 public expect class KMMEdPublicKey {
+
+    /**
+     * Method to verify a signature against the original message
+     *
+     * @param message ByteArray representing the original message
+     * @param sig ByteArray representing the signed message
+     * @return Boolean that tell us if the signature matches the original message
+     */
     fun verify(message: ByteArray, sig: ByteArray): Boolean
 }

apollo/src/commonMain/kotlin/io/iohk/atala/prism/apollo/utils/KMMX25519KeyPair.kt

@@ -2,6 +2,9 @@ package io.iohk.atala.prism.apollo.utils
 
 import kotlin.js.ExperimentalJsExport
 
+/**
+ * Interface defining the functionality for generating KMMX25519 key pairs.
+ */
 @OptIn(ExperimentalJsExport::class)
 expect class KMMX25519KeyPair(privateKey: KMMX25519PrivateKey, publicKey: KMMX25519PublicKey) {
     val privateKey: KMMX25519PrivateKey

apollo/src/commonMain/kotlin/io/iohk/atala/prism/apollo/utils/KMMX25519PrivateKey.kt

@@ -1,3 +1,6 @@
 package io.iohk.atala.prism.apollo.utils
 
+/**
+ * Definition of the KMMX25519PrivateKey functionality
+ */
 expect class KMMX25519PrivateKey

apollo/src/commonMain/kotlin/io/iohk/atala/prism/apollo/utils/KMMX25519PublicKey.kt

@@ -1,3 +1,6 @@
 package io.iohk.atala.prism.apollo.utils
 
+/**
+ * Definition of the KMMX25519PublicKey functionality
+ */
 expect class KMMX25519PublicKey

apollo/src/commonMain/kotlin/io/iohk/atala/prism/apollo/utils/X25519KeyPairGeneration.kt

@@ -3,6 +3,9 @@ package io.iohk.atala.prism.apollo.utils
 import kotlin.js.ExperimentalJsExport
 import kotlin.js.JsExport
 
+/**
+ * Interface defining the functionality for generating X25519 key pairs.
+ */
 @ExperimentalJsExport
 @JsExport
 interface X25519KeyPairGeneration {