(IOS) Extract PKCS7 from MIME and Decrypt

Extracts the base64-encoded PKCS7 body of a MIME message to a file, and then decrypts using Chilkat Crypt2.

Download: Chilkat IOS (IPhone) Objective-C Libraries

NSMutableString *strOutput = [NSMutableString stringWithCapacity:1000];

CkoMime *mime = [[[CkoMime alloc] init] autorelease];

BOOL success;
success = [mime UnlockComponent: @"Anything for 30-day trial"];
if (success == NO) {
    [strOutput appendString: mime.LastErrorText];
    [strOutput appendString: @"\n"];
    self.mainTextField.stringValue = strOutput;
    return;
}

success = [mime LoadMimeFile: @"c:/aaworkarea/EmailInBytes.txt"];
if (success != YES) {
    [strOutput appendString: mime.LastErrorText];
    [strOutput appendString: @"\n"];
    self.mainTextField.stringValue = strOutput;
    return;
}

success = [mime SaveBody: @"c:/aaworkarea/smime.p7m"];
if (success != YES) {
    [strOutput appendString: mime.LastErrorText];
    [strOutput appendString: @"\n"];
    self.mainTextField.stringValue = strOutput;
    return;
}

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

success = [crypt UnlockComponent: @"Anything for 30-day trial"];
if (success == NO) {
    [strOutput appendString: crypt.LastErrorText];
    [strOutput appendString: @"\n"];
    self.mainTextField.stringValue = strOutput;
    return;
}

success = [crypt AddPfxSourceFile: @"c:/aaworkarea/my.pfx" password: @"pfxPassword"];
if (success == NO) {
    [strOutput appendString: crypt.LastErrorText];
    [strOutput appendString: @"\n"];
    self.mainTextField.stringValue = strOutput;
    return;
}

//  Indicate the public-key (PKCS7) encryption/decryption should be used:
crypt.CryptAlgorithm = @"pki";

NSString *inPath;
inPath = @"c:/aaworkarea/smime.p7m";
NSString *outPath;
outPath = @"c:/aaworkarea/decrypted.dat";

success = [crypt CkDecryptFile: inPath outFile: outPath];
if (success == NO) {
    [strOutput appendString: crypt.LastErrorText];
    [strOutput appendString: @"\n"];
    self.mainTextField.stringValue = strOutput;
    return;
}

[strOutput appendString: @"Success."];
[strOutput appendString: @"\n"];

self.mainTextField.stringValue = strOutput;