Dart Requires Chilkat v11.0.0+
Dart
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 Dart Downloads
import 'package:chilkat/chilkat.dart';
void main() {
// 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.
final sbRsaJwk = CkStringBuilder();
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('}');
final rsaKey = CkPublicKey();
try {
rsaKey.loadFromString(sbRsaJwk.getAsString());
} on ChilkatException catch (e) {
print(e.lastErrorText);
return;
}
// ---------------------------------------------------
// Use the following ECC public key loaded from JWK format.
final sbEccJwk = CkStringBuilder();
sbEccJwk.append('{"kty":"EC",');
sbEccJwk.append('"crv":"P-256",');
sbEccJwk.append('"x":"f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU",');
sbEccJwk.append('"y":"x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0"');
sbEccJwk.append('}');
final eccKey = CkPublicKey();
try {
eccKey.loadFromString(sbEccJwk.getAsString());
} on ChilkatException catch (e) {
print(e.lastErrorText);
return;
}
// ---------------------------------------------------
// The HMAC key (in base64url format)
final 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"
// }
// ]
// }
final sbJws = CkStringBuilder();
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('}');
final jws = CkJws();
try {
jws.loadJwsSb(sbJws);
} on ChilkatException catch (e) {
print(e.lastErrorText);
return;
}
// The payload is easily accessible:
print('Payload: ${jws.getPayload('utf-8')}');
final sbKeyId = CkStringBuilder();
final bCaseSensitive = false;
final protHeader = CkJsonObject();
final numSignatures = jws.numSignatures;
var i = 0;
while (i < numSignatures) {
try {
jws.getProtectedH(i, protHeader);
} on ChilkatException catch (e) {
print(e.lastErrorText);
return;
}
print('--------------------------');
print('$i: ');
// Get the protected header.
protHeader.emitCompact = false;
print(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', bCaseSensitive)) {
jws.setPublicKey(i, rsaKey);
}
if (sbKeyId.contentsEqual('myEcKey', bCaseSensitive)) {
jws.setPublicKey(i, eccKey);
}
if (sbKeyId.contentsEqual('myMacKey', bCaseSensitive)) {
jws.setMacKey(i, hmacKey, 'base64url');
}
// Validate this signature.
final v = jws.validate(i);
if (v < 0) {
// Perhaps Chilkat was not unlocked or the trial expired..
print('Validate failed for some other reason.');
print(jws.lastErrorText);
} else {
if (v == 0) {
print('Invalid signature. The key was incorrect, the JWS was invalid, or both.');
} else {
print('Signature validated.');
}
}
i++;
}
// 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.
}