(Objective-C) RSAES-OAEP Encrypt/Decrypt Binary Data with AES-128 and SHA56

Demonstrates the use of the new EncryptBd and DecryptBd methods introduced in Chilkat v9.5.0.67 to create a PKCS7/CMS (Cryptographic Message Syntax) message using RSAES-OAEP with AES-128 and SHA256.

Note: This example requires Chilkat v9.5.0.67 or greater.

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

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

// Load a small JPG file to be encrypted/decrypted.
CkoBinData *jpgBytes = [[CkoBinData alloc] init];
BOOL success = [jpgBytes LoadFile: @"qa_data/jpg/starfish20.jpg"];
if (success != YES) {
    NSLog(@"%@",@"Failed to load JPG file.");
    return;
}

// Show the unencrypted JPG bytes in Base64 format.
// (The "base64_mime" encoding was added in Chilkat v9.5.0.67.
// The "base64" encoding emits a single line of base64, whereas
// "base64_mime" will emit multi-line base64 as it would appear
// in MIME.)
NSLog(@"%@",[jpgBytes GetEncoded: @"base64_mime"]);

// Sample base64_mime JPG data:

// /9j/4AAQSkZJRgABAQEASABIAAD//gAmRmlsZSB3cml0dGVuIGJ5IEFkb2JlIFBob3Rvc2hvcD8g
// NC4w/9sAQwAQCwwODAoQDg0OEhEQExgoGhgWFhgxIyUdKDozPTw5Mzg3QEhcTkBEV0U3OFBtUVdf
// YmdoZz5NcXlwZHhcZWdj/9sAQwEREhIYFRgvGhovY0I4QmNjY2NjY2NjY2NjY2NjY2NjY2NjY2Nj
// Y2NjY2NjY2NjY2NjY2NjY2NjY2NjY2NjY2Nj/8IAEQgAFAAUAwERAAIRAQMRAf/EABcAAAMBAAAA
// AAAAAAAAAAAAAAIDBAX/xAAYAQADAQEAAAAAAAAAAAAAAAABAgMEAP/aAAwDAQACEAMQAAAB2kZY
// NNEijWKddfTmLgALWH//xAAbEAACAgMBAAAAAAAAAAAAAAABAgMRAAQSE//aAAgBAQABBQL0XqN+
// pM2aqJGMiqFFCyg7z//EABwRAAICAgMAAAAAAAAAAAAAAAERAAIQIQMSUf/aAAgBAwEBPwHqU5aq
// Axx+y1tMQl4elj//xAAcEQEAAQUBAQAAAAAAAAAAAAABEQACEBIhA1H/2gAIAQIBAT8B3Bhqy7Zc
// enyiwmGgDhiOzj//xAAdEAABAwUBAAAAAAAAAAAAAAABAAIREBIhIkFR/9oACAEBAAY/ArZyn+Cg
// xtxWuJaoCnqDuin/xAAcEAABBAMBAAAAAAAAAAAAAAABABEhYRAxQVH/2gAIAQEAAT8hkEwPUUR9
// DYfE4nxtRpIkBTsayuALIiuY/9oADAMBAAIAAwAAABDWPTsf/8QAGhEAAwADAQAAAAAAAAAAAAAA
// AAEREDFBIf/aAAgBAwEBPxC0DVPcWm+Ce4OesrkE6bjH/8QAGBEBAQEBAQAAAAAAAAAAAAAAAREA
// QRD/2gAIAQIBAT8QahMiOc8YgSrnTY3ELclHXn//xAAcEAEBAAIDAQEAAAAAAAAAAAABEQAhMUFx
// EFH/2gAIAQEAAT8Qn3igmSZSj+c4N4zapMy9IjFV98wncN2iuLFsCEbDGxQkI6RO/n//2Q==

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

// Specify the encryption to be used.
// "pki" indicates "Public Key Infrastructure" and will create a PKCS7/CMS message.
crypt.CryptAlgorithm = @"pki";
crypt.Pkcs7CryptAlg = @"aes";
crypt.KeyLength = [NSNumber numberWithInt:128];
crypt.OaepHash = @"sha256";
crypt.OaepPadding = YES;

// A certificate is needed as the encryption key..
CkoCert *cert = [[CkoCert alloc] init];
success = [cert LoadFromFile: @"qa_data/rsaes-oaep/cert.pem"];
if (success != YES) {
    NSLog(@"%@",cert.LastErrorText);
    return;
}

// Tell the crypt object to use the certificate.
[crypt SetEncryptCert: cert];

// Do the in-place RSAES-OAEP encryption.
// The contents of jpgBytes are replaced with the CMS message.
success = [crypt EncryptBd: jpgBytes];
if (success != YES) {
    NSLog(@"%@",crypt.LastErrorText);
    return;
}

// Examine the JPG bytes again.  The bytes should be different because they are encrypted:
NSLog(@"%@",[jpgBytes GetEncoded: @"base64_mime"]);

// Sample CMS message:
// This CMS message can be copy-and-pasted into the online web form
// at https://lapo.it/asn1js/   to verify the algorithms used.

// MIIFDAYJKoZIhvcNAQcDoIIE/TCCBPkCAQAxggGgMIIBnAIBADB1MGgxCzAJBgNVBAYTAlVTMQsw
// CQYDVQQIDAJJTDEQMA4GA1UEBwwHV2hlYXRvbjEhMB8GA1UECgwYSW50ZXJuZXQgV2lkZ2l0cyBQ
// dHkgTHRkMRcwFQYDVQQDDA5DaGlsa2F0V2lkZ2V0cwIJAMRwugDmvniwMBwGCSqGSIb3DQEBBzAP
// oA0wCwYJYIZIAWUDBAIBBIIBAHyWLgkJfIvoA3cYEAR/uHfA7uoi4eQXHl2woQAd6W5BbUNVBcYD
// zuCTTOTWo1e7Uh0j0AhMZvVQf3+cngTiimzKwIZ2LNuNAgYOhrO/7coHyB22ImVetncUpCsAv/u7
// 2tYp1dO36T56K+2hMELwcQXTj6v5ODO6a3emdCjITCjHhlYePvq2l0HyU2ALG5RFB6ldk9imhKzn
// 6gfcijfH65S+KfMRlFBCXFu5nCBKmi8Ywo8Ue0rFssUDKLCjCeQNY52symiDbN/d06K/luOUwVhY
// 1KQffdIKmTrZUugw+FaoQRq0xGj39T/sYu8qCinNZu/vPdUmxcXszSaSVJ/LGwcwggNOBgkqhkiG
// 9w0BBwEwHQYJYIZIAWUDBAECBBDLnqRASqqnNUV2IiDkTRl/gIIDIPRaxdKEjhR5RD7pc7yI5j7N
// TioZNvuMETdHWgHy7eOGz+1hP7fObk/RI0mtQx7IPEjkxaduNbXNzTpXAVRVj4Fw1zzXlqh9UPwt
// p3TN3NsVRPQ5GmQ+cnPTSZD8i3i8ru8WFHyj1M6vyA0phrEGltKgqsZbb+OkuO5qG3laJv4XGkmn
// 039pPGSTydQzW+HAp/hsJZLEMwdngXToi854ytjEk+ahCkeOz+d2MAfXZAR+nBCkmAmCQ9SDVTqH
// FVJOAV2WrKBqNv4+iMn63f7QeoVIjk0QTE8D2iRsUiFYjy4ICaUpplLJEewneH5l0W40KA2+mOep
// lIrvWnaX2H8ltOEBGD6Jng7i6p/Q4Lr+Y+HBYIHsBPLox3A4NOh/b0MZcyBr/AV2CsIwkIUGLlYl
// /3rnpl7dRTuHP+fe1lDQVLAxD+U0c73sW7vOALhEe2t2Ae3ayukWPRyfXK9FNHAMhcOI4stHNSwx
// o2fHa+ctTpPh0V5CHY/ELAKKkrH3nW954pk52tc8Xt6CnzVO5ry/ndcmTlQA0PkG6CK98TE9hCTA
// hBdSL4/gVFgi9c35I6VXieY9kJe5ICljw5Ftm5yqTwlJIxGU3Z/WeIYBF4uyMegG75AQ9Md9tX0h
// w8OOu2b6sIvxOZ+durIrYQDlXUXU/IR9exzAlYFENNBPhBgtDsWKSx5gcp+32kC5wtSYSiy3JxNt
// 0W1yEJz8JGZXhuUvRXjwf+AjS4+/o82WTNXVLVKZ0TP50NVvtf9QqWuXvK/kDDPx6w+abK/aqdAs
// QSL7wCxOosR2YUPWbXtwGhyHbIfAwWXijO2RnrqKeXL25Ywg16LQUTHq9Mlbgfw/tx3l5pjrmqFC
// e9t9aaU6kDZqyyfRDOeWwkuDIsT90ulazbed2apgUXYj6AVVvMiC1pRld9wSuHH0vW0x5VsNbmXy
// EY0NJlJY6II/1szy3bpiP6MsqFveCyCX8rM7UgGgpMNbvWPnsX0F/0eJywIrXrnQYXpvfgghIrlr
// qu/ftXWypfcfvATxme+cN2EBsCDhq4VcMgB6JY3ykv6P8PK/QpMTbu4Y

// To decrypt, we'll need the cert with private key.  
// (The certificate alone contains only the public key.)
// Provide the required cert + private key from a PFX (.pfx/.p12) file.
success = [crypt AddPfxSourceFile: @"qa_data/rsaes-oaep/cert_plus_privatekey.pfx" password: @"PFX_PASSWORD"];
if (success != YES) {
    NSLog(@"%@",crypt.LastErrorText);
    return;
}

// Decrypt to restore back to the original:
success = [crypt DecryptBd: jpgBytes];
if (success != YES) {
    NSLog(@"%@",crypt.LastErrorText);
    return;
}

NSLog(@"%@",[jpgBytes GetEncoded: @"base64_mime"]);