(Objective-C) Create JWT Using RSA (RS256, RS384, or RS512)

Demonstrates how to create a JWT using an RSA private key. This is for JOSE headers with an "alg" of RS256, RS384, or RS512. When RSA is used, the private key signs (creates) the JWT, and the public key is for verification.

This example also demonstrates how to include time constraints:

• nbf: Not Before Time
• exp: Expiration Time
• iat: Issue At Time

Chilkat Objective-C Library Downloads MAC OS X (Cocoa) Libs iOS Libs

#import <CkoPrivateKey.h>
#import <CkoJwt.h>
#import <CkoJsonObject.h>
#import <NSString.h>

// Demonstrates how to create a JWT using an RSA private key.

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

CkoPrivateKey *privKey = [[CkoPrivateKey alloc] init];

// Load an RSA private key from a PEM file.
BOOL success = [privKey LoadEncryptedPemFile: @"qa_data/pem/rsa_passwd.pem" password: @"passwd"];
if (success != YES) {
    NSLog(@"%@",privKey.LastErrorText);
    return;
}

CkoJwt *jwt = [[CkoJwt alloc] init];

// Build the JOSE header
CkoJsonObject *jose = [[CkoJsonObject alloc] init];
// Use RS256.  Pass the string "RS384" or "RS512" to use RSA with SHA-384 or SHA-512.
success = [jose AppendString: @"alg" value: @"RS256"];
success = [jose AppendString: @"typ" value: @"JWT"];

// Now build the JWT claims (also known as the payload)
CkoJsonObject *claims = [[CkoJsonObject alloc] init];
success = [claims AppendString: @"iss" value: @"http://example.org"];
success = [claims AppendString: @"sub" value: @"John"];
success = [claims AppendString: @"aud" value: @"http://example.com"];

// Set the timestamp of when the JWT was created to now.
int curDateTime = [[jwt GenNumericDate: [NSNumber numberWithInt: 0]] intValue];
success = [claims AddIntAt: [NSNumber numberWithInt: -1] name: @"iat" value: [NSNumber numberWithInt: curDateTime]];

// Set the "not process before" timestamp to now.
success = [claims AddIntAt: [NSNumber numberWithInt: -1] name: @"nbf" value: [NSNumber numberWithInt: curDateTime]];

// Set the timestamp defining an expiration time (end time) for the token
// to be now + 1 hour (3600 seconds)
success = [claims AddIntAt: [NSNumber numberWithInt: -1] name: @"exp" value: [NSNumber numberWithInt: (curDateTime + 3600)]];

// Produce the smallest possible JWT:
jwt.AutoCompact = YES;

// Create the JWT token.  This is where the RSA signature is created.
NSString *token = [jwt CreateJwtPk: [jose Emit] payload: [claims Emit] key: privKey];

NSLog(@"%@",token);