MIME S/MIME Encryption Algorithm Properties

See more MIME Examples

Demonstrates the properties that control S/MIME encryption: Pkcs7CryptAlg (the symmetric content-encryption algorithm), Pkcs7KeyLength (the content-encryption key length in bits), OaepPadding (whether RSAES-OAEP key transport is used instead of RSAES-PKCS1-v1_5), and the OAEP hash settings OaepHash and OaepMgfHash. The properties are configured before calling Encrypt.

#import <CkoMime.h>
#import <CkoCert.h>

BOOL success = NO;

CkoMime *mime = [[CkoMime alloc] init];
success = [mime SetBodyFromPlainText: @"This message will be encrypted."];
if (success == NO) {
    NSLog(@"%@",mime.LastErrorText);
    return;
}

//  Pkcs7CryptAlg is the symmetric content-encryption algorithm.  Supported values are aes, aes-gcm,
//  des, 3des, and rc2.  The default is aes.
mime.Pkcs7CryptAlg = @"aes";

//  Pkcs7KeyLength is the content-encryption key length in bits.  The default is 128.
mime.Pkcs7KeyLength = [NSNumber numberWithInt:256];

//  OaepPadding selects the RSA key-transport padding.  The default is false (RSAES-PKCS1-v1_5).
//  Set true to use RSAES-OAEP, in which case the OAEP hash settings apply.
mime.OaepPadding = YES;
mime.OaepHash = @"sha256";
mime.OaepMgfHash = @"sha256";

//  Load the recipient certificate (public key is sufficient for encrypting).
CkoCert *cert = [[CkoCert alloc] init];
success = [cert LoadFromFile: @"qa_data/recipient.cer"];
if (success == NO) {
    NSLog(@"%@",cert.LastErrorText);
    return;
}

//  Encrypt using the algorithm settings configured above.
success = [mime Encrypt: cert];
if (success == NO) {
    NSLog(@"%@",mime.LastErrorText);
    return;
}

NSLog(@"%@%@%@%d%@",@"Encrypted with ",mime.Pkcs7CryptAlg,@" ",[mime.Pkcs7KeyLength intValue],@"-bit key.");