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.
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
It depends on your use case. You can’t broadly claim “superiority”. (I mean, yes you can, in some cases, but to be strict about it, you can’t really). But there are areas where MD5 has been broken: For starters: MD5 is old, and common. There are tons of rainbow tables against it, and they’re easy … Read more
System.Security.Cryptography.RandomNumberGenerator is the base class for Cryptographically-Secure Pseudo-Random Number Generator (CSPRNG) implementations. In .NET Framework RandomNumberGenerator.Create() returns an RNGCryptoServiceProvider instance (unless configured differently by CryptoConfig). In .NET Core RandomNumberGenerator.Create() returns an opaque type which is based on BCryptGenRandom (Windows) or OpenSSL’s random number generator (!Windows). RandomNumberGenerator.Create() is the only way to get an RNG instance … Read more
Since everyone until now has simply defined what a hash function was, I will bite. A one-way function is not just a hash function — a function that loses information — but a function f for which, given an image y (“SE” or 294 in existing answers), it is difficult to find a pre-image x … Read more
From one of my favorite books ever, Applied Cryptography by Bruce Schneier “If someone created a database of all primes, won’t he be able to use that database to break public-key algorithms? Yes, but he can’t do it. If you could store one gigabyte of information on a drive weighing one gram, then a list … Read more
There is no security hole by sending the IV in cleartext – this is similar to storing the salt for a hash in plaintext: As long as the attacker has no control over the IV/salt, and as long as it is random, there is no problem.
In practice and with respect to security, no, mathematically, yes. If you have a private key (N, D), there is algebraically an infinite number of solutions to the equation 1 = E*D (mod Phi(N)). However, if you make two such solutions (E, N) and (E’, N) that both satisfy the equation public, you will have … Read more
The size of a RSA key is expressed in bits, not bytes. 2048 bits are 256 bytes. A bare-bone RSA private key consists in two integers, the modulus (a big composite integer, its length in bits is the “RSA key length”) and the private exponent (another big integer, which normally has the same size than … Read more
RSA doesn’t pick from a list of known primes: it generates a new very large number, then applies an algorithm to find a nearby number that is almost certainly prime. See this useful description of large prime generation): The standard way to generate big prime numbers is to take a preselected random number of the … Read more