Validate a JWS Signature

See more JSON Web Signatures (JWS) Examples

Demonstrates Jws.Validate, which validates exactly one signature, identified by a zero-based index, using the key configured at that same index.

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

BOOL success = NO;

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

//  Load the JWS compact serialization.
NSString *jwsCompact = @"eyJhbGciOiJIUzI1NiJ9.VGhpcyBpcyB0aGUgY29udGVudCB0byBzaWduLg.<signature>";
success = [jws LoadJws: jwsCompact];
if (success == NO) {
    NSLog(@"%@",jws.LastErrorText);
    return;
}

//  Provide the key for signature 0 (here an HMAC key).
NSString *base64Key = @"YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU=";
success = [jws SetMacKey: [NSNumber numberWithInt: 0] key: base64Key encoding: @"base64"];
if (success == NO) {
    NSLog(@"%@",jws.LastErrorText);
    return;
}

//  Validate the signature identified by the zero-based index, using the key configured at that index.
//  Validate returns 1 when the signature or MAC is cryptographically valid, 0 when it is not, or a
//  negative value on error.
int v = [[jws Validate: [NSNumber numberWithInt: 0]] intValue];
if (v < 0) {
    NSLog(@"%@",jws.LastErrorText);
    return;
}

if (v != 1) {
    NSLog(@"%@",@"The signature is not valid.");
    return;
}

NSLog(@"%@",@"The signature is valid.");