(Objective-C) Create CAdES p7m using AWS KMS to Sign in the Cloud

See more Signing in the Cloud Examples

Demonstrates how to create a CAdES p7m, using AWS KMS. The signing of the hash happens in the Cloud on AWS KMS. Everything else regarding the creation of CAdES happens locally within Chilkat.

Note: This example requires Chilkat v9.5.0.96 or greater.

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

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

// Load the certificate used for signing.  The certificate's private key is stored in AWS KMS
// However, we still need the certificate locally (without private key).
CkoCert *cert = [[CkoCert alloc] init];
BOOL success = [cert LoadFromFile: @"qa_data/certs/myCert.cer"];
if (success == NO) {
    NSLog(@"%@",cert.LastErrorText);
    return;
}

// Here's a screenshot showing the key ID of a private key in AWS KMS:


// To sign using AWS KMS, 
// add the following lines of code to specify your AWS authentication credentials,
// and the ID of the KMS private key.
CkoJsonObject *jsonAwsKms = [[CkoJsonObject alloc] init];
// Set the "service" equal to "aws_kms" to tell Chilkat to use AWS KMS for signing.
[jsonAwsKms UpdateString: @"service" value: @"aws_kms"];
[jsonAwsKms UpdateString: @"access_key" value: @"ACCESS_KEY"];
[jsonAwsKms UpdateString: @"secret_key" value: @"SECRET_KEY"];
// Make sure to specify the correct region for your case.
[jsonAwsKms UpdateString: @"region" value: @"us-west-2"];
// In the above screenshot, our key ID is "187012e8-008f-4fc7-b100-5efe6146dff2".  You will use your key ID.
[jsonAwsKms UpdateString: @"key_id" value: @"187012e8-008f-4fc7-b100-5efe6146dff2"];

success = [cert SetCloudSigner: jsonAwsKms];

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

success = [crypt SetSigningCert: cert];
if (success == NO) {
    NSLog(@"%@",crypt.LastErrorText);
    return;
}

// The CadesEnabled property applies to all methods that create PKCS7 signatures. 
// To create a CAdES-BES signature, set this property equal to true.
crypt.CadesEnabled = YES;

crypt.HashAlgorithm = @"sha256";

CkoJsonObject *signedAttrs = [[CkoJsonObject alloc] init];
[signedAttrs UpdateInt: @"contentType" value: [NSNumber numberWithInt: 1]];
[signedAttrs UpdateInt: @"signingTime" value: [NSNumber numberWithInt: 1]];
[signedAttrs UpdateInt: @"messageDigest" value: [NSNumber numberWithInt: 1]];
[signedAttrs UpdateInt: @"signingCertificateV2" value: [NSNumber numberWithInt: 1]];
crypt.SigningAttributes = [signedAttrs Emit];

// You can sign any type of file..
NSString *inputXmlPath = @"qa_data/e-Invoice.xml";
NSString *outputP7mPath = @"qa_output/signed.p7m";

// Create the CAdES-BES attached signature, which contains the original data.
// Chilkat will build the .p7m locally, but will (internally) use ARSS
// to do the RSA signing remotely.
success = [crypt CreateP7M: inputXmlPath p7mPath: outputP7mPath];
if (success == NO) {
    NSLog(@"%@",crypt.LastErrorText);
    return;
}

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