(Objective-C) Generate RSA SSH Key

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Generates an RSA SSH key and saves to various public and private key file formats (OpenSSH and PuTTY).

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#import <CkoSshKey.h>
#import <NSString.h>

CkoSshKey *key = [[CkoSshKey alloc] init];

// numBits may range from 384 to 4096.  Typical values are
// 1024 or 2048.  (must be a multiple of 64)
// A good choice for the exponent is 65537.  Chilkat recommends
// always using this value.
int numBits = 2048;
int exponent = 65537;
BOOL success = [key GenerateRsaKey: [NSNumber numberWithInt: numBits] exponent: [NSNumber numberWithInt: exponent]];
if (success != YES) {
    NSLog(@"%@",@"Bad params passed to RSA key generation method.");
    return;
}

// Note: Generating a public/private key pair is CPU intensive
// and may take a short amount of time (more than few seconds,
// but less than a minute).

NSString *exportedKey = 0;
BOOL exportEncrypted;

// Export the RSA private key to OpenSSH, PuTTY, and XML and save. 
exportEncrypted = NO;
exportedKey = [key ToOpenSshPrivateKey: exportEncrypted];
// Chilkat provides a SaveText method for convenience...
success = [key SaveText: exportedKey path: @"privkey_openssh_unencrypted.pem"];

// Export with encryption to OpenSSH private key format:
key.Password = @"secret";
exportEncrypted = YES;
exportedKey = [key ToOpenSshPrivateKey: exportEncrypted];
success = [key SaveText: exportedKey path: @"privkey_openssh_encrypted.pem"];

// Export the RSA private key to unencrypted PuTTY format:
exportEncrypted = NO;
exportedKey = [key ToPuttyPrivateKey: exportEncrypted];
success = [key SaveText: exportedKey path: @"privkey_putty_unencrypted.ppk"];

// Export the RSA private key to encrypted PuTTY format:
key.Password = @"secret";
exportEncrypted = YES;
exportedKey = [key ToPuttyPrivateKey: exportEncrypted];
success = [key SaveText: exportedKey path: @"privkey_putty_encrypted.ppk"];

// Export private key to XML:
exportedKey = [key ToXml];
success = [key SaveText: exportedKey path: @"privkey.xml"];

// ----------------------------------------------------
// Now for the public key....
// ----------------------------------------------------

// The Secure Shell (SSH) Public Key File Format
// is documented in RFC 4716.
exportedKey = [key ToRfc4716PublicKey];
success = [key SaveText: exportedKey path: @"pubkey_rfc4716.pub"];

// OpenSSH has a separate public-key file format, which 
// is also supported by Chilkat SshKey:
exportedKey = [key ToOpenSshPublicKey];
success = [key SaveText: exportedKey path: @"pubkey_openSsh.pub"];

NSLog(@"%@",@"Finished.");