Objective-C

Get RSA Public Key in JWK Format (JSON Web Key)

See more JSON Web Signatures (JWS) Examples

Demonstrates how to get an RSA public key in JWK (JSON Web Key) format.

Note: This example requires Chilkat v9.5.0.66 or later.

Objective-C

#import <CkoStringBuilder.h>
#import <CkoPublicKey.h>
#import <NSString.h>
#import <CkoJsonObject.h>

BOOL success = NO;

// Note: This example requires Chilkat v9.5.0.66 or later.

// Load a PEM file into memory.
CkoStringBuilder *sbPem = [[CkoStringBuilder alloc] init];
success = [sbPem LoadFile: @"qa_data/pem/rsa_public.pem" charset: @"utf-8"];
if (success != YES) {
    NSLog(@"%@",@"Failed to load PEM file.");
    return;
}

// Load the PEM into a public key object.
CkoPublicKey *pubKey = [[CkoPublicKey alloc] init];
success = [pubKey LoadFromString: [sbPem GetAsString]];
if (success != YES) {
    NSLog(@"%@",pubKey.LastErrorText);
    return;
}

// Get the public key in JWK format:
NSString *jwk = [pubKey GetJwk];

// The GetJwk method will return the JWK in the most compact JSON format possible,
// as a single line with no extra whitespace.  To get a more human-readable JWK (for this example),
// load into a Chilkat JSON object and emit non-compact:

CkoJsonObject *json = [[CkoJsonObject alloc] init];
[json Load: jwk];
json.EmitCompact = NO;
NSLog(@"%@",@"RSA Public Key in JWK format:");
NSLog(@"%@",[json Emit]);

// Sample output:
// { 
//   "kty": "RSA",
//   "n": "33TqqLR3eeUmDtHS89qF3p4MP7Wfqt2Zjj3lZjLjjCGDvwr9cJNlNDiuKboODgUiT4ZdPWbOiMAfDcDzlOxA04DDnEFGAf-kDQiNSe2ZtqC7bnIc8-KSG_qOGQIVaay4Ucr6ovDkykO5Hxn7OU7sJp9TP9H0JH8zMQA6YzijYH9LsupTerrY3U6zyihVEDXXOv08vBHk50BMFJbE9iwFwnxCsU5-UZUZYw87Uu0n4LPFS9BT8tUIvAfnRXIEWCha3KbFWmdZQZlyrFw0buUEf0YN3_Q0auBkdbDR_ES2PbgKTJdkjc_rEeM0TxvOUf7HuUNOhrtAVEN1D5uuxE1WSw",
//   "e": "AQAB"
// }

// Additional information can be added like this:
[json AppendString: @"use" value: @"enc"];
[json AppendString: @"kid" value: @"123ABC"];

// Now examine the JSON:
NSLog(@"%@",[json Emit]);

// { 
//   "kty": "RSA",
//   "n": "33TqqLR3eeUmDtHS89qF3p4MP7Wfqt2Zjj3lZjLjjCGDvwr9cJNlNDiuKboODgUiT4ZdPWbOiMAfDcDzlOxA04DDnEFGAf-kDQiNSe2ZtqC7bnIc8-KSG_qOGQIVaay4Ucr6ovDkykO5Hxn7OU7sJp9TP9H0JH8zMQA6YzijYH9LsupTerrY3U6zyihVEDXXOv08vBHk50BMFJbE9iwFwnxCsU5-UZUZYw87Uu0n4LPFS9BT8tUIvAfnRXIEWCha3KbFWmdZQZlyrFw0buUEf0YN3_Q0auBkdbDR_ES2PbgKTJdkjc_rEeM0TxvOUf7HuUNOhrtAVEN1D5uuxE1WSw",
//   "e": "AQAB",
//   "use": "enc",
//   "kid": "123ABC"
// }