(Objective-C) Working with PEM Encrypted Private Keys

Demonstrates how to load and save PEM encrypted private keys.

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#import <CkoGlobal.h>
#import <CkoPem.h>
#import <NSString.h>
#import <CkoFileAccess.h>
#import <CkoPrivateKey.h>

// Starting in v9.5.0.49, all Chilkat classes can be unlocked at once at the beginning of a program
// by calling UnlockBundle.  It requires a Bundle unlock code.
CkoGlobal *chilkatGlob = [[CkoGlobal alloc] init];
BOOL success = [chilkatGlob UnlockBundle: @"Anything for 30-day trial."];
if (success != YES) {
    NSLog(@"%@",chilkatGlob.LastErrorText);
    return;
}

CkoPem *pem = [[CkoPem alloc] init];

NSString *pemPassword = @"secret";

// To load a PEM file containing encrypted private keys, simply
// provide the password.
success = [pem LoadPemFile: @"/Users/chilkat/testData/pem/pemContainingEncryptedPrivateKeys.pem" password: pemPassword];
if (success != YES) {
    NSLog(@"%@",pem.LastErrorText);
    return;
}

CkoFileAccess *fac = [[CkoFileAccess alloc] init];
NSString *pemText = [fac ReadEntireTextFile: @"/Users/chilkat/testData/pem/pemContainingEncryptedPrivateKeys.pem" charset: pemPassword];

// To load a PEM from a string, call LoadPem instead of LoadPemFile:
success = [pem LoadPem: pemText];
if (success != YES) {
    NSLog(@"%@",pem.LastErrorText);
    return;
}

// A few notes:
// The PEM may contain both private keys and certificates (or anything else).
// The password is utilized for whatever content in the PEM is encrypted.  
// It is OK to have both encrypted and non-encrypted content within a given PEM.

// PEM private keys can be encrypted in different formats.  The LoadPem and LoadPemFile
// methods automatically handle the different formats.
// One format is PKCS8 and is indicated by this delimiter within the PEM:

// -----BEGIN ENCRYPTED PRIVATE KEY-----
// MIICoTAbBgkqhkiG9w0BBQMwDgQIfdD0zv24lgkCAggABIICgE0PdHJmRbNs6cBX
// ...

// Another format, we'll call "passphrase" looks like this in the PEM:
// -----BEGIN RSA PRIVATE KEY-----
// Proc-Type: 4,ENCRYPTED
// DEK-Info: DES-EDE3-CBC,A4215544D11C5D0C
// 
// paqy9XRexcSjurHfG0xhCaUD0HrvIdhuC0CbRxxxeMlkLaV6+uT80rBxt2AaibWG
// ...

// Show the bit length of each private key:
int i;
int numPrivateKeys = [pem.NumPrivateKeys intValue];
if (numPrivateKeys == 0) {
    NSLog(@"%@",(@"Error: Expected the PEM to contain private keys."));
    return;
}

for (i = 1; i <= numPrivateKeys; i++) {
    CkoPrivateKey *privKey = [pem GetPrivateKey: [NSNumber numberWithInt: (i - 1)]];
    NSLog(@"%d%@%d%@",i,@": ",[privKey.BitLength intValue],@" bits");

}