Objective-C

Create PKCS7 (CMS) EnvelopedData

Encrypt some data to a recipient by creating a PKCS7 (CMS) EnvelopedData structure. The data will be encrypted using a symmetric content-encryption algorithm (e.g., AES), and the randomly generated symmetric key will be encrypted using the recipient’s RSA public key extracted from their X.509 certificate. Objective-C

#import <CkoCrypt2.h>
#import <CkoCert.h>
#import <NSString.h>

BOOL success = NO;

CkoCrypt2 *crypt = [[CkoCrypt2 alloc] init];

//  Specify the encryption to be used.
//  "pki" indicates "Public Key Infrastructure" and will create a PKCS7 encrypted (enveloped-data) message.
crypt.CryptAlgorithm = @"pki";
crypt.Pkcs7CryptAlg = @"aes";
crypt.KeyLength = [NSNumber numberWithInt:256];
crypt.OaepHash = @"sha256";
crypt.OaepPadding = YES;

CkoCert *cert = [[CkoCert alloc] init];

//  Use a certificate found in the Windows certificate store.
success = [cert LoadByCommonName: @"My Certificate"];
if (success != YES) {
    NSLog(@"%@",cert.LastErrorText);
    return;
}

//  Tell the crypt object to use the certificate.
[crypt SetEncryptCert: cert];

NSString *toBeEncrypted = @"This string is to be encrypted.";

//  Get the result in multi-line BASE64 MIME format.
crypt.EncodingMode = @"base64_mime";
crypt.Charset = @"utf-8";

NSString *result = [crypt EncryptStringENC: toBeEncrypted];
if (success != YES) {
    NSLog(@"%@",crypt.LastErrorText);
    return;
}

//  -------------------------------------------------------------------------
//  See the following example to decrypt what was created in this example
//  Decrypt PKCS7 (CMS) EnvelopedData
//  -------------------------------------------------------------------------

NSLog(@"%@",result);

//  Sample output:

//  MIICSgYJKoZIhvcNAQcDoIICOzCCAjcCAQAxggHiMIIB3gIBADCBljCBgTELMAkGA1UEBhMCSVQx
//  EDAOBgNVBAgMB0JlcmdhbW8xGTAXBgNVBAcMEFBvbnRlIFNhbiBQaWV0cm8xFzAVBgNVBAoMDkFj
//  dGFsaXMgUy5wLkEuMSwwKgYDVQQDDCNBY3RhbGlzIENsaWVudCBBdXRoZW50aWNhdGlvbiBDQSBH
//  MwIQPCWvkSv8oQ7xRmEHJ6TzEDA8BgkqhkiG9w0BAQcwL6APMA0GCWCGSAFlAwQCAQUAoRwwGgYJ
//  KoZIhvcNAQEIMA0GCWCGSAFlAwQCAQUABIIBAKqHAPQNSsQoX7B2NH7QyEOWQRsSVs8oCHXmy8f4
//  MVZD2er3bvYUCIomxpwbLEAl14qjUIMynahooYGgqip7+4FqL301G+BVjZVfEhHWj+VI1dAWnWuL
//  VHlvc/pbQNBWqV8rKVJsNIsuAZkdj4WSwLVKxYkYX43B8fh/g71XN2DTJu7Z/824v48KBmgpQBOT
//  2q7IcDGxNPAFN2p6eavIVGn2LvhEbf/Fszyj+GR5tMcnQP1BOLJ3s3JzUBbvj8hcZrF1Vhl9HnTU
//  YQx8G/KdW1mR+Wlhl3BWoK0LYKRTbnTx2BXOs0CY1SXOAdhKr01ZYjA+xW4nGzY0lfXS9QZjh9gw
//  TAYJKoZIhvcNAQcBMB0GCWCGSAFlAwQBKgQQw0xTbfmnt0zjWHo5SaQIp4AgxTVY9E/Ncqy6t+RM
//  8y4c3Av62/wB8IpPUEmtM2OeuZo=