Question

Hello all
I need to encrypt text what is the best encryption to use programmatically ?
In general I have input file with string that I need to encrypt then read the file in the application
Decrypt it for the application flow .
with c++

Answer 1

The strongest encryption is to use a one-time pad (with XOR for example). The one time pad algorithm (unlike most other commonly used algorithms) is provably secure when used correctly.

One serious problem with this algorithm is that the distribution of the one-time pad must be done securely and this is often impractical. If it were possible to transmit the one time pad securely then it would typically also be possible to send the message securely using the same channel.

In situations where it is not possible to send information securely via another channel, public key cryptography is used. Generally the strength of these algorithms increases as the key length increases, unless some critical weakness is found in the algorithm. RSA is a commonly used public key algorithm.

To get strong encryption with public key cryptography the keys tend to be large (thousands of bits is not uncommon) and the algorithms are slow to compute. An alternative is to use a symmetric key algorithm instead. These can often get the same strength encryption with shorter keys and can be faster to encrypt and decrypt. Like one-time-pads this also has the problem of key distribution, but this time the key is very short so it is more feasible to be able to transfer it securely. An example of a commonly used symmetric key algorithm is AES.