(Objective-C) Sign String to create a CAdES-T Signature

This example will sign a string to create a CAdEST-T signature.

Note: This example requires Chilkat v9.5.0.78 or greater.

Chilkat Objective-C Library Downloads MAC OS X (Cocoa) Libs iOS Libs

#import <CkoCrypt2.h>
#import <CkoCert.h>
#import <CkoJsonObject.h>
#import <NSString.h>
#import <CkoBinData.h>

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

CkoCrypt2 *crypt = [[CkoCrypt2 alloc] init];

// This example will use the certificate + private key currently inserted into a smartcard reader.
CkoCert *cert = [[CkoCert alloc] init];

// If we wish to provide the smartcard PIN (otherwise the user will be prompted by the operating system).
cert.SmartCardPin = @"000000";
BOOL success = [cert LoadFromSmartcard: @""];
if (success != YES) {
    NSLog(@"%@",cert.LastErrorText);
    return;
}

// Note: It is also possible to use certs from .pfx/.p12, .pem, or other sources such as 
// pre-installed Windows certificates.

success = [crypt SetSigningCert: cert];

// Use SHA-256 rather than the default of SHA-1
crypt.HashAlgorithm = @"sha256";

// Create JSON that tells Chilkat what signing attributes to include:
CkoJsonObject *attrs = [[CkoJsonObject alloc] init];
[attrs UpdateBool: @"contentType" value: YES];
[attrs UpdateBool: @"signingTime" value: YES];
[attrs UpdateBool: @"messageDigest" value: YES];
[attrs UpdateBool: @"signingCertificateV2" value: YES];

// A CAdES-T signature is one that includes a timestampToken created by an online TSA (time stamping authority).
// We must include the TSA's URL, as well as a few options to indicate what is desired.
// Except for the TSA URL, the options shown here are typically what you would need.
[attrs UpdateBool: @"timestampToken.enabled" value: YES];
[attrs UpdateString: @"timestampToken.tsaUrl" value: @"https://freetsa.org/tsr"];
[attrs UpdateBool: @"timestampToken.addNonce" value: NO];
[attrs UpdateBool: @"timestampToken.requestTsaCert" value: YES];
[attrs UpdateString: @"timestampToken.hashAlg" value: @"sha256"];

crypt.SigningAttributes = [attrs Emit];

NSString *strToSign = @"THIS IS MY ID";

CkoBinData *bd = [[CkoBinData alloc] init];
[bd AppendString: strToSign charset: @"utf-8"];

// This creates the CAdES-T signature.  During the signature creation, it
// communicates with the TSA to get a timestampToken.
// The contents of bd are signed and replaced with the CAdES-T signature (which embeds the original content).
success = [crypt OpaqueSignBd: bd];
if (success != YES) {
    NSLog(@"%@",crypt.LastErrorText);
    return;
}

// Get the signature in base64 format:
NSLog(@"%@",[bd GetEncoded: @"base64_mime"]);

// Or save the signature to a file.
[bd WriteFile: @"qa_output/cades-t_sample.p7m"];

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