Objective-C

Sign String to create a CAdES-T Signature, using HTTP Proxy to Access Timestamp Server

This example will sign a string to create a CAdEST-T signature. It will use an HTTP proxy to access the timestamp server. Objective-C

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

BOOL success = NO;

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

CkoCert *cert = [[CkoCert alloc] init];
cert.SmartCardPin = @"123456";
success = [cert LoadFromSmartcard: @""];
if (success != YES) {
    NSLog(@"%@",cert.LastErrorText);
    return;
}

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 = @"Hello World!";

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

//  -------------------------------------------------------------------------
//  The purpose of this example is to show how an HTTP object with custom
//  settings can be used to access the Internet when signing.
//  Access to the Internet is needed to communicate with the timestamp server.
CkoHttp *http = [[CkoHttp alloc] init];
//  This can be a domain name, hostname, or IP address.
http.ProxyDomain = @"172.16.16.56";
http.ProxyPort = [NSNumber numberWithInt:808];
http.ProxyLogin = @"myProxyLogin";
http.ProxyPassword = @"myProxyPassword";
[crypt SetTsaHttpObj: http];
//  -------------------------------------------------------------------------

//  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"]);

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