(Objective-C) Load ECC Private Key from JWK Format (JSON Web Key)

Demonstrates how to load an ECC private key from JWK (JSON Web Key) format.

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

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

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

// First build a JWK sample to load..
CkoJsonObject *json = [[CkoJsonObject alloc] init];
[json UpdateString: @"kty" value: @"EC"];
[json UpdateString: @"crv" value: @"P-256"];
[json UpdateString: @"x" value: @"oBUyo8CQAFPeYPvv78ylh5MwFZjTCLQeb042TjiMJxE"];
[json UpdateString: @"y" value: @"vvQyxZkUjJQUPU_0bCy3Pj5qQdfu8jwEfqEeYGZ95CU"];
[json UpdateString: @"d" value: @"EbVzfPnZPxfAyxqEZV05laAoJAl-_6Xt2O4mOB611sM"];

// The JSON contains the following:
// { 
//   "kty": "EC",
//   "crv": "P-256",
//   "x": "oBUyo8CQAFPeYPvv78ylh5MwFZjTCLQeb042TjiMJxE",
//   "y": "vvQyxZkUjJQUPU_0bCy3Pj5qQdfu8jwEfqEeYGZ95CU",
//   "d": "EbVzfPnZPxfAyxqEZV05laAoJAl-_6Xt2O4mOB611sM"
// }

// 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];

CkoPrivateKey *privKey = [[CkoPrivateKey alloc] init];
success = [privKey LoadJwk: jwkStr];
if (success != YES) {
    NSLog(@"%@",privKey.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(@"%@",[privKey GetXml]);

// XML output:
// <ECCKeyValue curve="secp256r1">MHcCAQEEIBG1c3z52T8XwMsahGVdOZWgKCQJfv+l7djuJjgetdbDoAoGCCqGSM49AwEHoEQDQgAEoBUyo8CQAFPeYPvv78ylh5MwFZjTCLQeb042TjiMJxG+9DLFmRSMlBQ9T/RsLLc+PmpB1+7yPAR+oR5gZn3kJQ==</ECCKeyValue>

NSLog(@"%@",[privKey GetPkcs8EncryptedPem: @"secret"]);

// PEM output
// 
// -----BEGIN ENCRYPTED PRIVATE KEY-----
// MIHFMEAGCSqGSIb3DQEFDTAzMBsGCSqGSIb3DQEFDDAOBAiku9rUjavLQQICCAAw
// FAYIKoZIhvcNAwcECGsl/5nLai+JBIGAVIqKAdfcRQNLl1t3x+n8OZ92d1H+qgjS
// Hs83wn2joJK4nlqy+rzosZxQ3e8NTJQyUEWZWcjqMj/N0phS3QWtcD/qbda5oEcv
// QgtU60cZ4ql3truefAmlZz2PdpOfqtYhxlvjJQxnyojn4ntj69OwLOt9SZbaBQQi
// KUL8KXT4Pq8=
// -----END ENCRYPTED PRIVATE KEY-----