Objective-C

Export a Public Key as DER into a BinData

Demonstrates the Chilkat PublicKey.GetDerBd method, which writes the public key as binary DER into a BinData. The first argument selects the representation (as for GetPem) and the second is the BinData that receives the bytes (its contents are replaced).

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 in-memory binary export: the raw DER lands in a BinData ready to hash, transmit, or hand to another API without a temporary file. It is the BinData counterpart to the text exporters, and the first argument picks the same PKCS #1 versus SubjectPublicKeyInfo structure.

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Objective-C

#import <CkoPublicKey.h>
#import <CkoBinData.h>

BOOL success = NO;

//  Load a public key to export.  LoadFromFile inspects the content, so it accepts DER, PEM, XML,
//  JWK, and other supported representations.
CkoPublicKey *pubKey = [[CkoPublicKey alloc] init];
success = [pubKey LoadFromFile: @"qa_data/public.pem"];
if (success == NO) {
    NSLog(@"%@",pubKey.LastErrorText);
    return;
}

//  Write the public key as binary DER into a BinData.  The 1st argument selects the representation
//  (as for GetPem) and the 2nd is the BinData that receives the bytes (its contents are replaced).
BOOL preferPkcs1 = NO;
CkoBinData *bd = [[CkoBinData alloc] init];
success = [pubKey GetDerBd: preferPkcs1 bd: bd];
if (success == NO) {
    NSLog(@"%@",pubKey.LastErrorText);
    return;
}

NSLog(@"%@%d%@",@"Exported ",[bd.NumBytes intValue],@" DER bytes.");