Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>I got Paul Kocher implementation from <a href="http://www.schneier.com/blowfish-download.html" rel="nofollow">Bruce Schneier's website</a>. And here is how an encryption method may look like: </p> <pre><code>#define PADDING_PHRASE @" " #import "CryptoUtilities.h" #import "blowfish.h" #import "NSData+Base64Utilities.h" @implementation CryptoUtilities + (NSString *)blowfishEncrypt:(NSData *)messageData usingKey:(NSData *)secretKey { NSMutableData *dataToEncrypt = [messageData mutableCopy]; if ([dataToEncrypt length] % 8) { NSMutableData *emptyData = [[PADDING_PHRASE dataUsingEncoding:NSUTF8StringEncoding] mutableCopy]; emptyData.length = 8 - [dataToEncrypt length] % 8; [dataToEncrypt appendData:emptyData]; } // Here we have data ready to encipher BLOWFISH_CTX ctx; Blowfish_Init (&amp;ctx, (unsigned char*)[secretKey bytes], [secretKey length]); NSRange aLeftRange, aRightRange; NSData *aLeftBox, *aRightBox; unsigned long dl = 0, dr = 0; for (int i = 0; i &lt; [dataToEncrypt length]; i += 8) { // Divide data into octets... // …and then into quartets aLeftRange = NSMakeRange(i, 4); aRightRange = NSMakeRange(i + 4, 4); aLeftBox = [dataToEncrypt subdataWithRange:aLeftRange]; aRightBox = [dataToEncrypt subdataWithRange:aRightRange]; // Convert bytes into unsigned long [aLeftBox getBytes:&amp;dl length:sizeof(unsigned long)]; [aRightBox getBytes:&amp;dr length:sizeof(unsigned long)]; // Encipher Blowfish_Encrypt(&amp;ctx, &amp;dl, &amp;dr); // Put bytes back [dataToEncrypt replaceBytesInRange:aLeftRange withBytes:&amp;dl]; [dataToEncrypt replaceBytesInRange:aRightRange withBytes:&amp;dr]; } return [dataToEncrypt getBase64String]; } </code></pre> <p>I am not really good in C, but it seems that my implementation works correctly. To decrypt you need just repeat same steps, but instead of <i>Blowfish_Encrypt</i> you need to call <i>Blowfish_Decrypt</i>.<br> Here is a source code for that (I assume that you just decrypt the cipher text, but don't deal with padding here):</p> <pre><code>+ (NSData *)blowfishDecrypt:(NSData *)messageData usingKey:(NSData *)secretKeyData { NSMutableData *decryptedData = [messageData mutableCopy]; BLOWFISH_CTX ctx; Blowfish_Init (&amp;ctx, (unsigned char*)[secretKeyData bytes], [secretKeyData length]); NSRange aLeftRange, aRightRange; NSData *aLeftBox, *aRightBox; unsigned long dl = 0, dr = 0; for (int i = 0; i&lt; [decryptedData length]; i += 8) { // Divide data into octets... // …and then into quartets aLeftRange = NSMakeRange(i, 4); aRightRange = NSMakeRange(i + 4, 4); aLeftBox = [decryptedData subdataWithRange:aLeftRange]; aRightBox = [decryptedData subdataWithRange:aRightRange]; // Convert bytes into unsigned long [aLeftBox getBytes:&amp;dl length:sizeof(unsigned long)]; [aRightBox getBytes:&amp;dr length:sizeof(unsigned long)]; // Decipher Blowfish_Decrypt(&amp;ctx, &amp;dl, &amp;dr); // Put bytes back [decryptedData replaceBytesInRange:aLeftRange withBytes:&amp;dl]; [decryptedData replaceBytesInRange:aRightRange withBytes:&amp;dr]; } return decryptedData; } </code></pre> <p>You might want to return pure bytes or Base64 string. For the last case I have a category, which adds an initialiser, which initialises NSData object with Base64 string and a method, which allows to get Base64 string from NSData.</p> <p>You should also think about playing with PADDING_PHRASE, for example, what if you want to add not just several spaces, but some random bytes? In this case you should send a padding length somehow.</p> <p><strong>Update:</strong> Actually, you <strong>should not</strong> use PADDING_PRASE in your process. Instead, you should use one of the standard algorithms for block ciphers described on <a href="http://en.wikipedia.org/wiki/Padding_%28cryptography%29#Block_cipher_mode_of_operation" rel="nofollow">Wikipedia page</a> </p>
    singulars
    1. This table or related slice is empty.
    1. POHow to implement Blowfish algorithm in iOS
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USStas
    1. USStas
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POHow to implement Blowfish algorithm in iOS
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. CONote on your code: You should only add emptyData if [dataToEncrypt length] % 8 != 0.
      singulars
      1. PO
      1. USggfela
    2. COThis is brilliant, I can't quite get to work the other way for decrypt though, do you have a sample code?
      singulars
      1. PO
      1. USperrohunter
    3. CO@ggfela of course, thank you. Actually, I've taken Cryptography course on Coursera and there were some strict rules about padding. You can read about those in [Wikipedia article](http://en.wikipedia.org/wiki/Padding_(cryptography)#Block_cipher_mode_of_operation) and implement any.
      singulars
      1. PO
      1. USStas
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload