Tutorial by Examples: crypto

// Create an array with a fixed size and type. var array = new Uint8Array(5); // Generate cryptographically random values crypto.getRandomValues(array); // Print the array to the console console.log(array); crypto.getRandomValues(array) can be used with instances of the following classes...

By default the Python random module use the Mersenne Twister PRNG to generate random numbers, which, although suitable in domains like simulations, fails to meet security requirements in more demanding environments. In order to create a cryptographically secure pseudorandom number, one can use Syst...

The following example encrypts data by using a hybrid cryptosystem consisting of AES GCM and OAEP, using their default parameter sizes and an AES key size of 128 bits. OAEP is less vulnerable to padding oracle attacks than PKCS#1 v1.5 padding. GCM is also protected against padding oracle attacks. ...

Random and ThreadLocalRandom are good enough for everyday use, but they have a big problem: They are based on a linear congruential generator, an algorithm whose output can be predicted rather easily. Thus, these two classes are not suitable for cryptographic uses (such as key generation). One can ...

So, have you ever wondered how to use your PEM RSA key pair that was generated by OpenSSL in Web Cryptography API? If the answers is yes. Great! You are going to find out. NOTE: This process can also be used for public key, you only need to change prefix and suffix to: -----BEGIN PUBLIC KEY----- ...

Python's built-in crypto functionality is currently limited to hashing. Encryption requires a third-party module like pycrypto. For example, it provides the AES algorithm which is considered state of the art for symmetric encryption. The following code will encrypt a given message using a passphrase...

RSA can be used to create a message signature. A valid signature can only be generated with access to the private RSA key, validating on the other hand is possible with merely the corresponding public key. So as long as the other side knows your public key they can verify the message to be signed by...

Asymmetric encryption has the advantage that a message can be encrypted without exchanging a secret key with the recipient of the message. The sender merely needs to know the recipients public key, this allows encrypting the message in such a way that only the designated recipient (who has the corre...

This class enables a programmer to create an object and protect its confidentiality with a cryptographic algorithm. Given any Serializable object, one can create a SealedObject that encapsulates the original object, in serialized format (i.e., a "deep copy"), and seals (encrypts) its seri...

Utilizing .Net System.Security.Cryptography.HashAlgorithm namespace to generate the message hash code with the algorithms supported. $example="Nobody expects the Spanish Inquisition." #calculate $hash=[System.Security.Cryptography.HashAlgorithm]::Create("sha256").ComputeHas...

To compute the hashes of relatively small blocks of data using different algorithms: final MessageDigest md5 = MessageDigest.getInstance("MD5"); final MessageDigest sha1 = MessageDigest.getInstance("SHA-1"); final MessageDigest sha256 = MessageDigest.getInstance("SHA-256&...

To generate samples of cryptographically random data: final byte[] sample = new byte[16]; new SecureRandom().nextBytes(sample); System.out.println("Sample: " + DatatypeConverter.printHexBinary(sample)); Produces output similar to: Sample: E4F14CEA2384F70B706B53A6DF8C5EFE Note...

Decryption Code public static string Decrypt(string cipherText) { if (cipherText == null) return null; byte[] cipherBytes = Convert.FromBase64String(cipherText); using (Aes encryptor = Aes.Create()) { Rfc2898DeriveBytes pdb = ...

There are times when the framework's Random() class may not be considered random enough, given that it is based on a psuedo-random number generator. The framework's Crypto classes do, however, provide something more robust in the form of RNGCryptoServiceProvider. The following code samples demonstr...