#import <VirgilKeys/VirgilKeys.h>

#import <VirgilFoundation/VirgilFoundation.h>

//...
VSSKeyPair *keyPair = [[VSSKeyPair alloc] init];
//...

#import <VirgilFoundation/VirgilFoundation.h>

//...
VSSKeyPair *keyPair = [[VSSKeyPair alloc] initWithPassword:<#password#>];
//...

#import <VirgilFoundation/VirgilFoundation.h>
#import <VirgilKit/VirgilKit.h>
#import <VirgilKeys/VirgilKeys.h>

//...
@property (nonatomic, strong) VSSKeysClient *keysClient;
//...
//...
// Create a new key pair
VSSKeyPair *keyPair = [[VSSKeyPair alloc] init];
// Create a new user data object
VSSUserData* userData = [[VSSUserData alloc] initWithDataClass:UDCUserId dataType:UDTEmail value:<#email address#>];
// Create a new public key candidate
VSSPublicKey *publicKey = [[VSSPublicKey alloc] initWithKey:pair.publicKey userDataList:@[ userData ]];
// Create a new instance of the keysClient
self.keysClient = [[VSSKeysClient alloc] initWithApplicationToken:<#Virgil Application Token#>];
// Pack the private key into container
VSSPrivateKey *pKey = [[VSSPrivateKey alloc] initWithKey:keyPair.privateKey password:nil];
// Create a request
[self.keysClient createPublicKey:publicKey privateKey:pKey completionHandler:^(VSSPublicKey *pubKey, NSError *error) {
    // Each request to the service is executed in a different background thread.
    // This completion handler is called NOT on the main thread.
    if (error != nil) {
        NSLog(@"Error creating public key object: '%@'", [error localizedDescription]);
        return;
    }

    // Process received pubKey...
    // NSLog(@"Created public key:");
    // NSLog(@"account_id: %@", pubKey.Id.containerId);
    // NSLog(@"public_key_id: %@", pubKey.Id.publicKeyId);
    // NSLog(@"user data attached: %lu", (unsigned long)pubKey.UserDataList.count);
}];
//...

#import <VirgilKeys/VirgilKeys.h>

//...
@property (nonatomic, strong) VSSKeysClient *keysClient;
//...
//...
// Assuming that keysClient was instantiated at some point before. If not - see 'Creating a new public key at the Virgil Keys Service' example.
// Send a request
[self.keysClient searchPublicKeyUserIdValue:<#email address#> completionHandler:^(VSSPublicKey *pubKey, NSError *error) {
    // Each request to the service is executed in a different background thread.
    // This completion handler is called NOT on the main thread.
    if (error != nil) {
        NSLog(@"Error getting public key object: '%@'", [error localizedDescription]);
        return;
    }

    // Process received pubKey... 
    // NSLog(@"Got the public key:");
    // NSLog(@"account_id: %@", pubKey.idb.containerId);
    // NSLog(@"public_key_id: %@", pubKey.idb.publicKeyId);
    // NSLog(@"%@", [[NSString alloc] initWithData:pubKey.key encoding:NSUTF8StringEncoding]);
}];
//...

//...
#import <VirgilFoundation/VirgilFoundation.h>
//...

// Assuming that we have some initial private string message.
NSString *message = @"This is a secret message which should be encrypted.";
// Convert it to the NSData
NSData *toEncrypt = [message dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:NO];
// Assuming that we have received a recepient's public key from the Virgil Keys Service.
// So, VSSPublicKey *recepientKey exists.

// Create a new VSSCryptor instance
VSSCryptor *cryptor = [[VSSCryptor alloc] init];
// Now we should add a key recepient (recepientKey is a VSSPublicKey instance received from the Virgil Keys Service)
[cryptor addKeyRecepient:<#recepientKey.idb.publicKeyId#> publicKey:<#recepientKey.key#>];
// And now we can easily encrypt the plain data
NSData *encryptedData = [cryptor encryptData:toEncrypt embedContentInfo:@YES];
// Now it is safe to send encryptedData to the recepient. Only person who holds the private key which corresponds to the recepientKey.Key public key is able to decrypt and read this data.
//...

//...
#import <VirgilFoundation/VirgilFoundation.h>
//...

// Assuming that we have received some data encrypted using our public key from the Virgil Keys Service.
// Assuming that we got VSSPublicKey instance of our public key from the Virgil Keys Service.
// Assuming that we have our private key which corresponds the public key from the Virgil Keys Service.
// Create a new VSSCryptor instance
VSSCryptor *decryptor = [[VSSCryptor alloc] init];
// Decrypt data
NSData *plainData = [decryptor decryptData:<#encryptedData#> publicKeyId:<#myPublicKey.idb.publicKeyId#> privateKey:<#myPrivateKey#> keyPassword:<# Private key password or nil #>];
// Compose initial message from the plain decrypted data
NSString *initialMessage = [[NSString alloc] initWithData:plainData encoding:NSUTF8StringEncoding];

//...
#import <VirgilFoundation/VirgilFoundation.h>
//...

// Assuming that we have some initial string message that we want to sign.
NSString *message = @"This is a message which should be signed.";
// Convert it to the NSData
NSData *toSign = [message dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:NO];
// Assuming that we have our private key.
// Create a new VSSSigner instance
VSSSigner *signer = [[VSSSigner alloc] init];
// Sign the initial data
NSData *signature = [signer signData:toSign privateKey:<#myPrivateKey#> keyPassword:<#password or nil#>];
if (signature.length > 0) {
    // Use composed signature data to make recipient sure about the sender identity.
    //...
}
//...

//...
#import <VirgilFoundation/VirgilFoundation.h>
//...

// Assuming that we get the public key of the user whose signature we need to verify from the Virgil Keys Service
// Assuming that we have a NSData object which was actually signed.
// Assuming that we have a NSData object with a signature.
// Create a new VSSSigner instance
VSSSigner *verifier = [[VSSSigner alloc] init];
// Verify signature against the signed data and sender's public key.
BOOL verified = [verifier verifySignature:<#signature#> data:<#signed data#> publicKey:<#senderKey.key#>];
if (verified) {
    // Sender is the real holder of the private key, so it might be trusted.
    //...
}
//...