MD5 is used both on its own and as a collisionresistance primitive in the asymmetric cryptography families: Digital Signature Schemes (DSA), also known as ElGamal, and the elliptic curve-based cryptography (ECC) . SHA is used by itself, as a hash function, in Message Authentication Codes. MD5 and SHA are widely accepted as cryptographic hashes of file data. As it was initially developed for the print media, MD5 can be used to digitally sign files and verify that they come from their claimed authors. The security of the MD5 hash function is based on its low collision rate and related tests. SHA is used in a much more comprehensive range of roles. It uses six standard hashing functions folded into one algorithm, combining hashes to create a larger hash output. This means it can be used as a hash function, as a checksum function, or even as a Hash-Based Message Authentication Code (HMAC), and since it is included in so many other cryptographic algorithms, most modern security protoc

The security behind SHA is derived from the size of the output values; if an attacker can find two inputs with the same hash value, then they could re-use that to forge data signatures and fool the authentication schemes. There are many different iterations of SHA, but all use the same essential hashing function, which means that the two most important properties of SHA, collision resistance and one-Waynes,

The methods for evaluating the security of cryptographic algorithms are of two general kinds: theoretical cryptanalysis and mathematical cryptanalysis. In the theoretical cryptanalysis, the goal is to show that a cryptographic algorithm is flawed in some way; in the mathematical cryptanalysis, the goal is to show that there exist significantly faster algorithms for performing a given task than a given cryptographic one . A lot of the Internet of Things sensors collect and transmit data with a simple structure, the recording of which takes only several or a dozen bits. The use of the methods described above requires augmenting the transmitted information with noise and then encoding it. Such a procedure generates additional costs, and its use adversely affects the functionality of power-limited devices.

Below will be presented an encryption algorithm with a very flexible block structure. These algorithms for the protection of very short information can work in blocks of minimal length, while if there is a need to encrypt longer information or increase the level of security, it is necessary to use more extensive blocks. 4. A cryptosystem inspired by the topologists sine curve Many popular cryptographic algorithms have been inspired by geometric structures. The topologists sine curve is a set of points: T = (cid:26)(cid:18) x, sin 1 x (cid:19) : x (0, 1] (cid:27) {x = 0 y [1, 1]} (1) Let us consider the arithmetic sequence xt, in the form: xt = x1 + (t 1)r, (2) where x1 and r are arbitrarily small positive real numbers and t {0, 1, 2, . . .}, then with any arbitrary, but fixed k N, we can define the function: fk : R+ {0} N, (3) given by the formula: fk(xt) := (cid:22) k sin