The strength of the SSL certificate can be determined by its higher level bit encryption. it is a means of securing a document by using a digital certificate to restrict access to the document’s contents except intended recipient. The bigger the key length the more time it takes for computer to break the code.
Generally there are 40 bit encryption, 128 bit encryption and 256 bit encryption.
40 bit: It is rarely used because it is feasible and can be easily cracked.
128/256 bit: This SSL encryption is strongly recommended for applications and websites. All banks use this type of encryption because it is computationally unfeasible to crack.