RSA (Rivest-Shamir-Adleman)

RSA algorithm was introduced by three researchers from MIT (Massachusetts Institute of Technology), namely Ron Rivest, Adi Shamir, and Len Adleman, in 1976. RSA encryption and decryption process based on the concept of prime numbers and modulo arithmetic. Both encryption and decryption keys are both integers. Encryption key is kept secret and public knowledge (so-called public key), but the key to decrypt the secret. Decryption key is made of several prime numbers together with the encryption key. To find the decryption key, a number is composite must be factored into prime factors. In fact, factoring nonprime numbers into prime factors is not easy. Currently no efficient algorithm found in factoring it. The greater number of the more difficult it nonprimanya pemfaktorannya. The more difficult pemfaktorannya, the stronger the RSA algorithm. In summary, the RSA algorithm is as follows. 

Strength and RSA Security As mentioned previously, the strength of the RSA algorithm lies in the level of difficulty of factoring numbers nonprime prime factor, which in this case n = ab. Once successfully factored n, then m = (a - 1) (b - 1). Furthermore, because the encryption key e is not suppressed, then the decryption key d can be calculated as well. This means that the decryption process can be done by people who are not eligible.
The inventor of the RSA algorithm suggests the value of a and b whose length is more than 100 digits. Thus the time will be measuring more than 200 digits. According to Rivest et al. for factoring numbers effort requires computation time for 4000 years! (Assuming a clock speed of the computer used 1 GHz).
Fortunately most efficient algorithm for factoring large numbers has not been found. This is what makes the RSA algorithm, but used as a powerful tool!
Suggestions to utilize and strengthen your RSA algorithm in processing files In processing the file, which is processed every byte. In a text file, byte represents a character. Compared with other cryptographic algorithms, file processing with the RSA algorithm requires a longer time. Thus, the plaintext and ciphertext blocks are used, it suggests the values ​​of each byte (from 0 to 255). However, if niali direct byte is used as a block, maybe there will still be leaked, because chiperteks to the same byte is the same. Therefore, the algorithm should be added to read two or more bytes at a time who later manipulate the bytes in such a way / trick that is unusual, provided that such manipulation must be reversible because it will use encryption and decryption algorithm inverse to each other. Thus, 99.99% guaranteed there can be no successful break.