Objective-C
Objective-C
Validate JWS with Multiple Signatures using the General JSON Serialization Format
See more JSON Web Signatures (JWS) Examples
Validates and recovers data and headers from a JSON Web Signature (JWS) containing 3 signatures.Note: Chilkat supports all of the following JWS algorithms:
+--------------+-------------------------------+--------------------+ | "alg" Param | Digital Signature or MAC | Implementation | | Value | Algorithm | Requirements | +--------------+-------------------------------+--------------------+ | HS256 | HMAC using SHA-256 | Required | | HS384 | HMAC using SHA-384 | Optional | | HS512 | HMAC using SHA-512 | Optional | | RS256 | RSASSA-PKCS1-v1_5 using | Recommended | | | SHA-256 | | | RS384 | RSASSA-PKCS1-v1_5 using | Optional | | | SHA-384 | | | RS512 | RSASSA-PKCS1-v1_5 using | Optional | | | SHA-512 | | | ES256 | ECDSA using P-256 and SHA-256 | Recommended+ | | ES384 | ECDSA using P-384 and SHA-384 | Optional | | ES512 | ECDSA using P-521 and SHA-512 | Optional | | PS256 | RSASSA-PSS using SHA-256 and | Optional | | | MGF1 with SHA-256 | | | PS384 | RSASSA-PSS using SHA-384 and | Optional | | | MGF1 with SHA-384 | | | PS512 | RSASSA-PSS using SHA-512 and | Optional | | | MGF1 with SHA-512 | | +--------------+-------------------------------+--------------------+
Chilkat Objective-C Downloads
#import <CkoStringBuilder.h>
#import <CkoPublicKey.h>
#import <NSString.h>
#import <CkoJws.h>
#import <CkoJsonObject.h>
BOOL success = NO;
// This requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.
// First, prepare the public keys that will be needed for each signature.
// ---------------------------------------------------
// Use the following RSA key loaded from JWK format.
CkoStringBuilder *sbRsaJwk = [[CkoStringBuilder alloc] init];
[sbRsaJwk Append: @"{\"kty\":\"RSA\","];
[sbRsaJwk Append: @"\"n\":\"ofgWCuLjybRlzo0tZWJjNiuSfb4p4fAkd_wWJcyQoTbji9k0l8W26mPddx"];
[sbRsaJwk Append: @"HmfHQp-Vaw-4qPCJrcS2mJPMEzP1Pt0Bm4d4QlL-yRT-SFd2lZS-pCgNMs"];
[sbRsaJwk Append: @"D1W_YpRPEwOWvG6b32690r2jZ47soMZo9wGzjb_7OMg0LOL-bSf63kpaSH"];
[sbRsaJwk Append: @"SXndS5z5rexMdbBYUsLA9e-KXBdQOS-UTo7WTBEMa2R2CapHg665xsmtdV"];
[sbRsaJwk Append: @"MTBQY4uDZlxvb3qCo5ZwKh9kG4LT6_I5IhlJH7aGhyxXFvUK-DWNmoudF8"];
[sbRsaJwk Append: @"NAco9_h9iaGNj8q2ethFkMLs91kzk2PAcDTW9gb54h4FRWyuXpoQ\","];
[sbRsaJwk Append: @"\"e\":\"AQAB\""];
[sbRsaJwk Append: @"}"];
CkoPublicKey *rsaKey = [[CkoPublicKey alloc] init];
success = [rsaKey LoadFromString: [sbRsaJwk GetAsString]];
if (success == NO) {
NSLog(@"%@",rsaKey.LastErrorText);
return;
}
// ---------------------------------------------------
// Use the following ECC public key loaded from JWK format.
CkoStringBuilder *sbEccJwk = [[CkoStringBuilder alloc] init];
[sbEccJwk Append: @"{\"kty\":\"EC\","];
[sbEccJwk Append: @"\"crv\":\"P-256\","];
[sbEccJwk Append: @"\"x\":\"f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU\","];
[sbEccJwk Append: @"\"y\":\"x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0\""];
[sbEccJwk Append: @"}"];
CkoPublicKey *eccKey = [[CkoPublicKey alloc] init];
success = [eccKey LoadFromString: [sbEccJwk GetAsString]];
if (success == NO) {
NSLog(@"%@",eccKey.LastErrorText);
return;
}
// ---------------------------------------------------
// The HMAC key (in base64url format)
NSString *hmacKey = @"AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow";
// The code below will verify each of the signatures in this JWS:
// {
// "payload": "SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu",
// "signatures": [
// {
// "protected": "eyJhbGciOiJSUzI1NiIsImtpZCI6Im15UnNhS2V5In0",
// "signature": "IPMQ02niTQDwLzsRZSCaEm9VEyAX_AVe3HWjniNt9kW-a8d6ZVbd2k6jGae8s1yIh0cgxDnXQ6-p6_sBI0cnMO0xpuJANhh2vFtNJl5lisad94-H3mB3lSfafRqxeYp5D8bh39BPv7y3PrUNVMQdKEJp_D5oJ0ROPTIYx3EG8eJQOx1HO0KqhcUo401XR6KSsIyFm5joBLNKTVzxZUTT1RRZZtwTdeZkbGevugIOX_9gHAtARpV6WaFA4Vvjnq8X9wPgqjWNCQRupadhTPz0JAsa-wy5vXQjsFlXAn43mDPpMfna5Ab3F5pS4yDwkbX6nRn7XBxH1SnnNJRFholQZw"
// },
// {
// "protected": "eyJhbGciOiJFUzI1NiIsImtpZCI6Im15RWNLZXkifQ",
// "signature": "1OQtaT3pgZmkDxvlfghvxL_8kX16WIen6u1MadEq1pA4qytA0--_EwZDNk00GDPWFpoJtKznibMZzLOg_UhHIw"
// },
// {
// "protected": "eyJhbGciOiJIUzI1NiIsImtpZCI6Im15TWFjS2V5In0",
// "signature": "YY8yVjmJJfy7YJOn3uUydG8WCY2PEuCvOLil5Ks5lnw"
// }
// ]
// }
CkoStringBuilder *sbJws = [[CkoStringBuilder alloc] init];
[sbJws Append: @"{ "];
[sbJws Append: @" \"payload\": \"SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu\","];
[sbJws Append: @" \"signatures\": ["];
[sbJws Append: @" { "];
[sbJws Append: @" \"protected\": \"eyJhbGciOiJSUzI1NiIsImtpZCI6Im15UnNhS2V5In0\","];
[sbJws Append: @" \"signature\": \"IPMQ02niTQDwLzsRZSCaEm9VEyAX_AVe3HWjniNt9kW-a8d6ZVbd2k6jGae8s1yIh0cgxDnXQ6-p6_sBI0cnMO0xpuJANhh2vFtNJl5lisad94-H3mB3lSfafRqxeYp5D8bh39BPv7y3PrUNVMQdKEJp_D5oJ0ROPTIYx3EG8eJQOx1HO0KqhcUo401XR6KSsIyFm5joBLNKTVzxZUTT1RRZZtwTdeZkbGevugIOX_9gHAtARpV6WaFA4Vvjnq8X9wPgqjWNCQRupadhTPz0JAsa-wy5vXQjsFlXAn43mDPpMfna5Ab3F5pS4yDwkbX6nRn7XBxH1SnnNJRFholQZw\""];
[sbJws Append: @" },"];
[sbJws Append: @" { "];
[sbJws Append: @" \"protected\": \"eyJhbGciOiJFUzI1NiIsImtpZCI6Im15RWNLZXkifQ\","];
[sbJws Append: @" \"signature\": \"1OQtaT3pgZmkDxvlfghvxL_8kX16WIen6u1MadEq1pA4qytA0--_EwZDNk00GDPWFpoJtKznibMZzLOg_UhHIw\""];
[sbJws Append: @" },"];
[sbJws Append: @" { "];
[sbJws Append: @" \"protected\": \"eyJhbGciOiJIUzI1NiIsImtpZCI6Im15TWFjS2V5In0\","];
[sbJws Append: @" \"signature\": \"YY8yVjmJJfy7YJOn3uUydG8WCY2PEuCvOLil5Ks5lnw\""];
[sbJws Append: @" }"];
[sbJws Append: @" ]"];
[sbJws Append: @"}"];
CkoJws *jws = [[CkoJws alloc] init];
success = [jws LoadJwsSb: sbJws];
if (success == NO) {
NSLog(@"%@",jws.LastErrorText);
return;
}
// The payload is easily accessible:
NSLog(@"%@%@",@"Payload: ",[jws GetPayload: @"utf-8"]);
CkoStringBuilder *sbKeyId = [[CkoStringBuilder alloc] init];
BOOL bCaseSensitive = NO;
CkoJsonObject *protHeader = [[CkoJsonObject alloc] init];
int numSignatures = [jws.NumSignatures intValue];
int i = 0;
while (i < numSignatures) {
success = [jws GetProtectedH: [NSNumber numberWithInt: i] json: protHeader];
if (success == NO) {
NSLog(@"%@",jws.LastErrorText);
return;
}
NSLog(@"%@",@"--------------------------");
NSLog(@"%d%@",i,@": ");
// Get the protected header.
protHeader.EmitCompact = NO;
NSLog(@"%@",[protHeader Emit]);
// Get the key ID ("kid") member.
// Note: In this example, the "kid" values are contained in the protected headers.
// They could've just as easily been located in unprotected headers. In that case,
// we would've called GetUnprotectedH instead of GetProtectedH(i).
[sbKeyId Clear];
[sbKeyId Append: [protHeader StringOf: @"kid"]];
// Set the key based on key ID.
if ([sbKeyId ContentsEqual: @"myRsaKey" caseSensitive: bCaseSensitive] == YES) {
[jws SetPublicKey: [NSNumber numberWithInt: i] pubKey: rsaKey];
}
if ([sbKeyId ContentsEqual: @"myEcKey" caseSensitive: bCaseSensitive] == YES) {
[jws SetPublicKey: [NSNumber numberWithInt: i] pubKey: eccKey];
}
if ([sbKeyId ContentsEqual: @"myMacKey" caseSensitive: bCaseSensitive] == YES) {
[jws SetMacKey: [NSNumber numberWithInt: i] key: hmacKey encoding: @"base64url"];
}
// Validate this signature.
int v = [[jws Validate: [NSNumber numberWithInt: i]] intValue];
if (v < 0) {
// Perhaps Chilkat was not unlocked or the trial expired..
NSLog(@"%@",@"Validate failed for some other reason.");
NSLog(@"%@",jws.LastErrorText);
}
else {
if (v == 0) {
NSLog(@"%@",@"Invalid signature. The key was incorrect, the JWS was invalid, or both.");
}
else {
NSLog(@"%@",@"Signature validated.");
}
}
i = i + 1;
}
// The output of this program is:
// Payload: In our village, folks say God crumbles up the old moon into stars.
// --------------------------
// 0:
// {
// "alg": "RS256",
// "kid": "myRsaKey"
// }
//
// Signature validated.
// --------------------------
// 1:
// {
// "alg": "ES256",
// "kid": "myEcKey"
// }
//
// Signature validated.
// --------------------------
// 2:
// {
// "alg": "HS256",
// "kid": "myMacKey"
// }
//
// Signature validated.