Casper Crypto Handle Package - Swift package for ObjectiveC call

About this package

This package provides Ed25519 and Secp256k1 crypto tasks as library for ObjectiveC call.

This package includes the following functions for both Secp256k1 and Ed25519:

(PrivateKey,PublicKey) generation
Sign message
Verify message
Read PrivateKey/PublicKey from PEM file
Write PrivateKey/PublicKey to PEM file

All the functions of the classes can be call from ObjectiveC to do the crypto tasks.

How to use this package from ObjectiveC package

From ObjectiveC package project, choose "Package.swift" file and add the following line of dependencies:

  dependencies: [
        .package(name: "CasperCryptoHandlePackage", url: "https://github.com/hienbui9999/CasperCryptoHandlePackage.git", from: "1.0.6"),
    ]

Save the "Package.swift" file, wait for a while for the Project to load the Swift Package.

Somehow it is like what is in this image, as you can see when the package is loaded, there will be "CasperCryptoHandlePackage 1.0.6" in the left panel

Create 1 ObjectiveC source file, add the following line of importing at the beginning of the file

@import CasperCryptoHandlePackage;

Now you can call Swift function of this package from ObjectiveC, such as this call to generate the (Private,Public) key pair, written in ObjectiveC:

-(CryptoKeyPair *) generateKey {
    CryptoKeyPair * ret = [[CryptoKeyPair alloc] init];
    Ed25519CrytoSwift * ed25519 = [[Ed25519CrytoSwift alloc] init];
    KeyPairClass * kpc = [ed25519 generateKeyPair];
    ret.privateKeyStr = kpc.privateKeyInStr;
    ret.publicKeyStr = kpc.publicKeyInStr;
    return ret;
}

in which the following call is call to Swift package function:

Ed25519CrytoSwift * ed25519 = [[Ed25519CrytoSwift alloc] init];
KeyPairClass * kpc = [ed25519 generateKeyPair];

Or if you wish to sign a message with Ed25519 crypto, in ObjectiveC you will write like this

-(NSString*) signMessageWithValue:(NSString*) messageToSign withPrivateKey:(NSString*) privateKeyStr {
    Ed25519CrytoSwift * ed25519 = [[Ed25519CrytoSwift alloc] init];
    NSString * ret = [ed25519 signMessageStringWithMessageToSign:messageToSign privateKeyStr:privateKeyStr];
    return ret;
}

This ObjectiveC function simply call the Swift function to sign the message

    Ed25519CrytoSwift * ed25519 = [[Ed25519CrytoSwift alloc] init];
    NSString * ret = [ed25519 signMessageStringWithMessageToSign:messageToSign privateKeyStr:privateKeyStr];

Here is a list of function provided by Swift for Ed25519 and Secp256k1:

public func generateKeyPair() -> KeyPairClass

public func getPrivateKeyStringForPemFile(privateKeyStr:String) -> String 

public func getPublicKeyStringForPemFile(publicKeyStr:String) -> String

public func getPrivateKeyStringFromPemString(pemStr: String) -> String

public func getPublicKeyStringFromPemString(pemStr: String) -> String 

public func signMessageString(messageToSign:String,privateKeyStr:String) -> String 

public func verifyMessage(signedMessage:String,publicKeyToVerifyString:String,originalMessage:String)-> Bool

Example of usage

Please refer to the Casper ObjectiveC SDK at this address https://github.com/tqhuy2018/Casper-ObjectiveC-sdk

This Swift package is used in the Crypto functions and Put Deploy function of the Casper ObjectiveC SDK