(Objective-C) RSA Signature SHA256withRSA, iso-8859-1, base64

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RSA sign the iso-8859-1 byte representation of a string with SHA256withRSA, and return the signature in the base64 encoding.

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

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

// This example will duplicate the following Java code:
// 
// Signature sign = Signature.getInstance("SHA256withRSA");
// sign.initSign(privateKey);
// sign.update(original.getBytes(Charset.forName("ISO-8859-1")));
// 
// ...
// byte[] resultado = sign.sign();
// sello = encodeByteArrayToBase64(resultado);
// 

// Load an RSA private key for signing.
// You can load any format file.  This example loads a .pem, but you can provide path to any type of file holding a private key.
CkoPrivateKey *privKey = [[CkoPrivateKey alloc] init];
BOOL success = [privKey LoadAnyFormatFile: @"qa_data/pem/rsa_passwd.pem" password: @"passwd"];
if (success != YES) {
    NSLog(@"%@",privKey.LastErrorText);
    return;
}

CkoRsa *rsa = [[CkoRsa alloc] init];
[rsa ImportPrivateKeyObj: privKey];

NSString *originalData = @"This is the string to be hashed an RSA signed.";

// Indicate that we want the iso-8859-1 byte representation of the string to be signed
rsa.Charset = @"iso-8859-1";

// We want the RSA signature in base64 format
rsa.EncodingMode = @"base64";

NSString *sigBase64 = [rsa SignStringENC: originalData hashAlg: @"sha256"];
NSLog(@"%@",sigBase64);