Algorithms are mathematical methods used to calculate a function. In the SSL market, algorithms are used to encrypt keys. Since the rise of the use of SSL and TLS to secure computer systems and applications, different algorithms have been used.
In 1976, Whitfield Diffie and Martin Hellman published a paper on public-key cryptography, in which the use of a private and public key combination was first mentioned. This form of encryption allows the transmission of a message encrypted with a public key that can only be decoded with the private key of that key pair. The first practical application of this principal was published in 1978 by Ronald Rivest, Adi Shamir and Len Adleman. Their RSA algorithm has been the encryption industry standard for decennia. This algorithm uses two prime numbers as the base for the calculation of the keys and always produces an encrypted result of a default value.
With the ever increasing calculative power of computers, and with it the possibility to crack these algorithms, the demand for heavier encryption algorithms that could handle that pressure rose. The RSA algorithm could cope with the increased demand at first by producing increasingly larger keys, but as the file size of these keys grew along with it, this was only a temporary fix. An algorithm that slowly but surely has started to replace the RSA algorithm is the ECC, or Elliptic Curve Cryptography, algorithm. This is based on the algebraic principle of the elliptic curve. Instead of a calculation based on two prime numbers, the public key is calculated by using an elliptic curve and a pre-determined value on that curve, and by finding several intersecting values on the curve with a separate calculation. The number of times this calculation is made is determined with the private key.
Despite the ECC algorithm being in use since 1985, mathematicians have yet to successfully trace its steps back to the private key. Compared to the RSA algorithm, the ECC algorithm is a lot more difficult to crack.
This also means that ECC keys can be kept much smaller when compared to the ever larger growing RSA keys, without having to sacrifice security for key size.