Objective-C

Export a Private Key as DER into a BinData

Demonstrates the Chilkat PrivateKey.GetPkcsBd method, which exports the key as DER into a BinData. The first argument selects PKCS #1 (true) versus PKCS #8 (false), the second is the password (empty for unencrypted), and the third is the BinData that receives the bytes.

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: This is the in-memory binary export — the raw DER bytes land in a BinData ready to hash, encrypt, or hand to another API without a temporary file. One method covers several cases: the boolean picks the traditional (PKCS #1) versus modern (PKCS #8) structure, and a nonempty password produces an encrypted PKCS #8 export (with the cipher from Pkcs8EncryptAlg). Source any password securely.

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Objective-C

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

BOOL success = NO;

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

//  The key password is not hard-coded in a real application; obtain it from an interactive
//  prompt, environment variable, or a secrets vault.
NSString *password = @"myKeyPassword";

//  Export the key as DER into a BinData.  The 1st argument selects PKCS #1 (true) versus PKCS #8
//  (false); the 2nd is the password (empty string for an unencrypted export); the 3rd is the
//  BinData that receives the DER bytes.
BOOL usePkcs1 = NO;
CkoBinData *bd = [[CkoBinData alloc] init];
success = [privKey GetPkcsBd: usePkcs1 password: password bd: bd];
if (success == NO) {
    NSLog(@"%@",privKey.LastErrorText);
    return;
}

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