Objective-C

Create an Opaque Signature with a Separate Private Key

Demonstrates the Chilkat Mime.ConvertToSignedPk method, which creates an opaque signature using a signer certificate and its separately supplied private key. The first argument is the Cert and the second is the PrivateKey.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: The separate-key form of ConvertToSigned, for when the certificate and private key are not bundled together. It produces the same opaque CMS signed-data result; only the source of the key material differs.

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Objective-C

#import <CkoMime.h>
#import <CkoCert.h>
#import <CkoPrivateKey.h>

BOOL success = NO;

CkoMime *mime = [[CkoMime alloc] init];
success = [mime SetBodyFromPlainText: @"This message will be signed."];
if (success == NO) {
    NSLog(@"%@",mime.LastErrorText);
    return;
}

//  Load the certificate and its private key separately.
CkoCert *cert = [[CkoCert alloc] init];
success = [cert LoadFromFile: @"qa_data/signer.cer"];
if (success == NO) {
    NSLog(@"%@",cert.LastErrorText);
    return;
}

CkoPrivateKey *privKey = [[CkoPrivateKey alloc] init];
success = [privKey LoadPemFile: @"qa_data/signer_privkey.pem"];
if (success == NO) {
    NSLog(@"%@",privKey.LastErrorText);
    return;
}

//  Create an opaque signature when the certificate and private key are supplied separately.  The
//  1st argument is the signer certificate and the 2nd is its private key.
success = [mime ConvertToSignedPk: cert privateKey: privKey];
if (success == NO) {
    NSLog(@"%@",mime.LastErrorText);
    return;
}

success = [mime SaveMime: @"qa_output/signed_opaque.eml"];
if (success == NO) {
    NSLog(@"%@",mime.LastErrorText);
    return;
}

NSLog(@"%@",@"Message converted to an opaque signed message.");