In this video, you will learn to describe the three encryption types used in modern cryptography including typical uses and advantages of each; symmetric, asymmetric, hash. On this section we will discuss three main types of cryptography or modern encryption types. There are the symmetric, the asymmetric and the hash functions. Symmetric Encryption, there are several cross of it or strengths both include the speed, and the fact that the cryptographic strength increases by bit of the key. So meaning, if we have a bigger key the cryptographic will be more secure. The up welling with Symmetric Encryption is that the key to be shared using a secure method sometimes an out-of-band method meaning we cannot send a key plaintext to the third party using an unsecured channel. Because as we discussed previously, the whole extent of the encryption algorithm or the algorithm is based on just one key and that key needs to remain secret at all times. DES, Triple DES and AES are just some of the examples that we currently use and AES is one of the most modern symmetric encryption that we currently us as up to date. On the other hand, asymmetric encryption uses two keys. Whitfield Diffie and Martin Hellman are the ones that created the Diffie-Hellman algorithm. They're considered the pioneers of the modern asymmetric encryption. On asymmetric encryption, we have to keys as I mentioned before. One key can be made publicly called public key and the other one needs to be kept private at all times, it is called the private key. Since we have two keys, one key is used to encrypt and the other one is used to decrypt. So basically whatever is encrypted with the public key can only be decrypted with the private key and the other way around as well. Whatever is encrypted with the private key can only really decrypted with the public key. Asymmetric encryption is used in digital certificates, it's used in public key infrastructures. It uses the one-way algorithm to generate the two keys. It's based on math like factoring prime numbers and discrete logarithm. This basically used for generating the two set of keys. It's actually a lot smaller than symmetric encryption and this is a reason why whenever we use asymmetric encryption most of the time we're using symmetric encryption as well. To put it in an example, whenever you visit a HTTPS website or a secure website, you use an asymmetric encryption first to exchange the key for the symmetric encryption to be used from that point forward. So basically as we discussed earlier, since we need to be able to exchange the key for the symmetric encryption in a secure manner, asymmetric encryption permits that we exchange one key between two nodes or two parties and from that point forward we'll be able to use symmetric encryption which is a lot faster in a secure manner. The hash functions provide encryption using a one-way algorithm and no key. This means that any length or a variable-length plaintext is hashed into a fixed-length hash value. This is often called message digest or simply a hash. This is used like we talked before for integrity. If a message or a plaintext changes and we can determine this by hashing that same plain text and checking the previous hash and the hash that we just did. In other words, if we generated a plaintext and we send it to somebody else with a corresponding hash and somebody changed that plaintext in transit, then we can determine if something is changing on that message using the previews hash generated and then the hash generated after the message arrived. SHA-1 and MD5 are older algorithms. They are prone to collisions and SHA-2 is the newer and recommended alternative. Hash functions are prone to collisions or that's one of the issues. SHA-1 and MD5 are the older algorithms that are more prone to collisions. A collision means two different plaintexts having the same hash. Again, since we have a limited amount of characters that the hash actually outputs, let's say MD5 outputs 15 characters or more, there is a possibility that two plaintexts can have the same exact hash volume or message digest. Those are called collisions.