Sign a JWS with a Private Key

See more JSON Web Signatures (JWS) Examples

Demonstrates Jws.SetPrivateKey, which sets the private key used to create a signature. The example uses RS256 (RSASSA-PKCS1-v1_5 with SHA-256).

The file path is relative to the application's current working directory. An absolute path may also be used. Supply the path appropriate to your own environment.

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

BOOL success = NO;

CkoJws *jws = [[CkoJws alloc] init];

//  Protected header specifying RSASSA-PKCS1-v1_5 with SHA-256 (RS256).
CkoJsonObject *header = [[CkoJsonObject alloc] init];
[header UpdateString: @"alg" value: @"RS256"];
success = [jws SetProtectedHeader: [NSNumber numberWithInt: 0] json: header];
if (success == NO) {
    NSLog(@"%@",jws.LastErrorText);
    return;
}

BOOL bIncludeBom = NO;
success = [jws SetPayload: @"This is the content to sign." charset: @"utf-8" includeBom: bIncludeBom];
if (success == NO) {
    NSLog(@"%@",jws.LastErrorText);
    return;
}

//  The file path is relative to the application's current working directory.  An absolute path
//  may also be used.  Supply the path appropriate to your own environment.
//  Load the signer's private key and set it for signature 0.
CkoPrivateKey *privKey = [[CkoPrivateKey alloc] init];
success = [privKey LoadPemFile: @"qa_data/signer_privkey.pem"];
if (success == NO) {
    NSLog(@"%@",privKey.LastErrorText);
    return;
}

success = [jws SetPrivateKey: [NSNumber numberWithInt: 0] privKey: privKey];
if (success == NO) {
    NSLog(@"%@",jws.LastErrorText);
    return;
}

NSString *jwsCompact = [jws CreateJws];
if (jws.LastMethodSuccess == NO) {
    NSLog(@"%@",jws.LastErrorText);
    return;
}

NSLog(@"%@",jwsCompact);