Encrypting with OpenSSL and CommonCrypto
<p>I'm trying to ultimately encrypt a file with OpenSSL and decrypt with Objective-c CommonCrypto, but before that works I need both approaches to encrypt the same way. </p>

<p>This is what I have:</p>

<p>String to encrypt: "This is the string"</p>

<p>Key: "thisisthekey"</p>

<p>OpenSSL:</p>

<pre><code>openssl enc -aes256 -a -e -nosalt -in InputFileWithString.txt -out OutputFile.txt thisisthekey
</code></pre>

<p>Resulting base 64 encoded string from openSSL: <code>HncUM4ryxSR7Rdi7Z49HPl9veOPxkk3l8GYIgorBhbk=</code></p>

<p>Objective-c CommonCrypto:</p>

<pre><code>+(NSString *)encryptText:(NSString *)text withKey:(NSString *)key{
    NSData *plainData = [text dataUsingEncoding:NSUTF8StringEncoding];

    NSData *encryptedData = [plainData AES256EncryptWithKey:key];

    NSString *base64String = [encryptedData base64EncodedStringWithOptions:0];

    return base64String;
}

- (NSData*)AES256EncryptWithKey:(NSString*)key {
    char keyPtr[kCCKeySizeAES256 + 1]; 
    bzero(keyPtr, sizeof(keyPtr)); 

    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];

    NSUInteger dataLength = [self length];

    size_t bufferSize           = dataLength + kCCBlockSizeAES128;
    void* buffer                = malloc(bufferSize);

    size_t numBytesEncrypted    = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,
                                          keyPtr, kCCKeySizeAES256,
                                          NULL,
                                          [self bytes], dataLength, 
                                          buffer, bufferSize,
                                          &amp;numBytesEncrypted);

    if (cryptStatus == kCCSuccess)
    {
        return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
    }

    free(buffer);
    return nil;
}
</code></pre>

<p>The resulting base 64 encoded string: <code>gNCs4d0GAxZHRcOtu8RVpLgN0ONKk1r5XkJ4GtL7W2I=</code></p>

<p>As you can see, each approach is producing a different encrypted string. Any ideas how to make these both produce the same string? </p>