1. RSA Messenger
With the rise of mobile usage it has become a popular tool for transmitting sensitive information. This sensitive information should be totally secure and reliable to exchange. This urgent need for secure SMS, led to drive for RSA implementation, which is considered one of the strongest algorithms in security. In this project I paid attention to maximize user's convenience and security. For this everytime when users use the program, there will be generated new keys(public key and private key) and cipher text is sent via whatsapp. The program is made by python(kivy). It has two language versions, English version and Korean version. You can use the program not only on computer(exe file) but also on Android(apk file) as you wish since we have two all kind of files.
What is RSA encyption?
RSA (Rivest–Shamir–Adleman) is a public-key cryptosystem that is widely used for secure data transmission. It is also one of the oldest. The acronym RSA comes from the surnames of Ron Rivest, Adi Shamir and Leonard Adleman, who publicly described the algorithm in 1977. An equivalent system was developed secretly, in 1973 at GCHQ (the British signals intelligence agency), by the English mathematician Clifford Cocks. That system was declassified in 1997. In a public-key cryptosystem, the encryption key is public and distinct from the decryption key, which is kept secret (private). An RSA user creates and publishes a public key based on two large prime numbers, along with an auxiliary value.
The prime numbers are kept secret. Messages can be encrypted by anyone, via the public key, but can only be decoded by someone who knows the prime numbers. The security of RSA relies on the practical difficulty of factoring the product of two large prime numbers, the "factoring problem". Breaking RSA encryption is known as the RSA problem. Whether it is as difficult as the factoring problem is an open question. There are no published methods to defeat the system if a large enough key is used. RSA is a relatively slow algorithm. Because of this, it is not commonly used to directly encrypt user data. More often, RSA is used to transmit shared keys for symmetric key cryptography, which are then used for bulk encryption-decryption.