Objective-C

Encrypt with Chilkat, Decrypt with OpenSSL

See more OpenSSL Examples

Demonstrates how to RSA encrypt a string using Chilkat, and then shows the corresponding OpenSSL command to RSA decrypt. The OpenSSL command to decrypt is as follows:

openssl rsautl -decrypt -inkey VP_Private.pem -in rsa_encrypted.bin -out original.txt

Objective-C

#import <CkoRsa.h>
#import <CkoPublicKey.h>
#import <NSString.h>
#import <CkoFileAccess.h>

BOOL success = NO;

//  This example requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

CkoRsa *rsa = [[CkoRsa alloc] init];

//  Note: RSA encryption uses the public key.  
//  RSA decryption uses the private key.
//  The reason is that the public key can be freely provided to anybody.  This allows anybody
//  to send an encrypted message to the private key owner, and only the private key owner 
//  can decrypt.
CkoPublicKey *key = [[CkoPublicKey alloc] init];

//  Load an RSA public key from a PEM file:
success = [key LoadFromFile: @"qa_data/pem/VP_Public.pem"];
if (success == NO) {
    NSLog(@"%@",key.LastErrorText);
    return;
}

//  Load the public key into the RSA object.
success = [rsa UsePublicKey: key];
if (success == NO) {
    NSLog(@"%@",rsa.LastErrorText);
    return;
}

NSString *strToEncrypt = @"00000000;XYZ2-3BHQ-ABCD-MMVV;6MY1-GHJK-9LRR;0";

//  The LittleEndian property is false by default, but it is set here
//  anyway to show that LittleEndian byte ordering is required for OpenSSL compatibility.
rsa.LittleEndian = NO;

BOOL usePrivateKey = NO;
NSData encryptedBytes;
encryptedBytes = [rsa EncryptString: strToEncrypt bUsePrivateKey: usePrivateKey];
if (rsa.LastMethodSuccess == NO) {
    NSLog(@"%@",rsa.LastErrorText);
    return;
}

//  The OpenSSL command to decrypt would be this:
//  openssl rsautl -decrypt -inkey VP_Private.pem -in rsa_encrypted.bin -out original.txt

CkoFileAccess *fac = [[CkoFileAccess alloc] init];
success = [fac WriteEntireFile: @"qa_output/rsa_encrypted.bin" fileData: encryptedBytes];
if (success == NO) {
    NSLog(@"%@",fac.LastErrorText);
    return;
}

NSLog(@"%@",@"RSA Encryption Succeeded.");