RSA, AES, DES, Eliptic Curve, Rijndael,  but the most elusive of them all is an encryption method whose cipher text can look like any type of encryption method inculding any type of plain text. Here is an example of cipher text using this method. See, you couldn't tell it apart because it has perfect secrecy in plain sight. This sounds secure, but the hardest part about encryption is not the algorythim, it is the key exchange.