The production in RFC 4122 (section 3, page 4), defines UUID string representation as UUID = time-low “-” time-mid “-” time-high-and-version “-” clock-seq-and-reserved clock-seq-low “-” node where each internal component is hex-encoded. Therefore, f47ac10b58cc4372a5670e02b2c3d479 is not a valid UUID representation.
The JCE Specification lists standard names that an implementation is expected to support. “SHA-1” is specified, as are SHA-256, SHA-384, and SHA-512. “SHA”, “SHA-0″ and SHA-2” are not standard names and therefore may not be supported at all. You cannot guarantee what “SHA” will return, if anything at all, because it is not in the … Read more
One organism’s large is another’s petite, though we all know expensive when we see it. Wink, wink. Try benchmarking something like the following in your environment and see where you’re at: EDIT 2/13/2012: The code has been updated as I’ve become (imperceptibly) smarter and also noticed a few cut’n’paste errors that had crept in. Mea … Read more
You want to use BigInteger.toByteArray() String msg = “Hello there!”; BigInteger bi = new BigInteger(msg.getBytes()); System.out.println(new String(bi.toByteArray())); // prints “Hello there!” The way I understand it is that you’re doing the following transformations: String —————–> byte[] ——————> BigInteger String.getBytes() BigInteger(byte[]) And you want the reverse: BigInteger ————————> byte[] ——————> String BigInteger.toByteArray() String(byte[]) Note that you … Read more
For a quick solution involving no external libraries, you can use hash<std::string> to hash strings. It’s defined by including the header files hash_map or unordered_map (or some others too). #include <string> #include <unordered_map> hash<string> hasher; string s = “heyho”; size_t hash = hasher(s); If you decide you want the added security of SHA, you don’t … Read more
An MD5 value is always 22 (useful) characters long in Base64 notation. Many Base64 algorithms will also append 2 characters of padding when encoding an MD5 hash, bringing the total to 24 characters. The padding adds no useful information and can be discarded. Only the first 22 characters matter. Here’s why: An MD5 hash is … Read more
Here’s a wild shot in the dark: We’re thinking about protecting the plaintext from the person doing the computation on it. But what if the objective was to protect both the plaintext AND the algorithm? Take, for example, MRI machines. The most expensive part of the MRI machine is the algorithm in which the machine … Read more
You have the wrong class imported for X509Certificate. You are likely looking for java.security.cert.X509Certificate not codec.x509.X509Certificate.
For “most purposes” the following options are recommended: Microsoft Base Cryptographic Provider Key Size: 2048 Exportable: Yes User Protected: Yes To be honest, I’m not familiar with the different CSPs, but the Base does the job every time for me. Key Size makes the keys harder to crack, but more than 2048-bits for a short … Read more