Objective-C

Load RSA Public Key from JWK Format (JSON Web Key)

See more RSA Examples

Demonstrates how to load an RSA public key from JWK (JSON Web Key) format.

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

Objective-C

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

BOOL success = NO;

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

//  First build a JWK sample to load..
CkoJsonObject *json = [[CkoJsonObject alloc] init];
[json UpdateString: @"kty" value: @"RSA"];
[json UpdateString: @"n" value: @"33TqqLR3eeUmDtHS89qF3p4MP7Wfqt2Zjj3lZjLjjCGDvwr9cJNlNDiuKboODgUiT4ZdPWbOiMAfDcDzlOxA04DDnEFGAf-kDQiNSe2ZtqC7bnIc8-KSG_qOGQIVaay4Ucr6ovDkykO5Hxn7OU7sJp9TP9H0JH8zMQA6YzijYH9LsupTerrY3U6zyihVEDXXOv08vBHk50BMFJbE9iwFwnxCsU5-UZUZYw87Uu0n4LPFS9BT8tUIvAfnRXIEWCha3KbFWmdZQZlyrFw0buUEf0YN3_Q0auBkdbDR_ES2PbgKTJdkjc_rEeM0TxvOUf7HuUNOhrtAVEN1D5uuxE1WSw"];
[json UpdateString: @"e" value: @"AQAB"];

//  The JSON contains the following:
//  { 
//    "kty": "RSA",
//    "n": "33TqqLR3eeUmDtHS89qF3p4MP7Wfqt2Zjj3lZjLjjCGDvwr9cJNlNDiuKboODgUiT4ZdPWbOiMAfDcDzlOxA04DDnEFGAf-kDQiNSe2ZtqC7bnIc8-KSG_qOGQIVaay4Ucr6ovDkykO5Hxn7OU7sJp9TP9H0JH8zMQA6YzijYH9LsupTerrY3U6zyihVEDXXOv08vBHk50BMFJbE9iwFwnxCsU5-UZUZYw87Uu0n4LPFS9BT8tUIvAfnRXIEWCha3KbFWmdZQZlyrFw0buUEf0YN3_Q0auBkdbDR_ES2PbgKTJdkjc_rEeM0TxvOUf7HuUNOhrtAVEN1D5uuxE1WSw",
//    "e": "AQAB",
//  } 

//  Note: The JSON can contain other members, such as "use", "kid", or anything else.  These will be ignored.
json.EmitCompact = NO;

//  Show the JWK string to be loaded:
NSString *jwkStr = [json Emit];

CkoPublicKey *pubKey = [[CkoPublicKey alloc] init];
//  The LoadFromString method will automatically detect the format.
success = [pubKey LoadFromString: jwkStr];
if (success != YES) {
    NSLog(@"%@",pubKey.LastErrorText);
    return;
}

//  OK.. the JWK is loaded.  It can be used in whatever way desired...

//  The key can be retrieved in any other format, such as XML or PEM..
NSLog(@"%@",[pubKey GetXml]);

//  XML output:
//  <RSAPublicKey>
//      <Modulus>33TqqLR3eeUmDtHS89qF3p4MP7Wfqt2Zjj3lZjLjjCGDvwr9cJNlNDiuKboODgUiT4ZdPWbOiMAfDcDzlOxA04DDnEFGAf+kDQiNSe2ZtqC7bnIc8+KSG/qOGQIVaay4Ucr6ovDkykO5Hxn7OU7sJp9TP9H0JH8zMQA6YzijYH9LsupTerrY3U6zyihVEDXXOv08vBHk50BMFJbE9iwFwnxCsU5+UZUZYw87Uu0n4LPFS9BT8tUIvAfnRXIEWCha3KbFWmdZQZlyrFw0buUEf0YN3/Q0auBkdbDR/ES2PbgKTJdkjc/rEeM0TxvOUf7HuUNOhrtAVEN1D5uuxE1WSw==</Modulus>
//      <Exponent>AQAB</Exponent>
//  </RSAPublicKey>

//  Choose PCKS1 or PCKS8 PEM format..
BOOL bPreferPkcs1 = NO;
NSLog(@"%@",[pubKey GetPem: bPreferPkcs1]);

//  PEM output
//  -----BEGIN PUBLIC KEY-----
//  MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA33TqqLR3eeUmDtHS89qF
//  3p4MP7Wfqt2Zjj3lZjLjjCGDvwr9cJNlNDiuKboODgUiT4ZdPWbOiMAfDcDzlOxA
//  04DDnEFGAf+kDQiNSe2ZtqC7bnIc8+KSG/qOGQIVaay4Ucr6ovDkykO5Hxn7OU7s
//  Jp9TP9H0JH8zMQA6YzijYH9LsupTerrY3U6zyihVEDXXOv08vBHk50BMFJbE9iwF
//  wnxCsU5+UZUZYw87Uu0n4LPFS9BT8tUIvAfnRXIEWCha3KbFWmdZQZlyrFw0buUE
//  f0YN3/Q0auBkdbDR/ES2PbgKTJdkjc/rEeM0TxvOUf7HuUNOhrtAVEN1D5uuxE1W
//  SwIDAQAB
//  -----END PUBLIC KEY-----