Previously I’ve discussed the cryptography of the Bitcoin blockchain. I mentioned that the ultimate confirmation of each block is the special hash which takes into account: - details of transactions confirmed by digital signatures - hash of the previous block - rightly picked number (nonce) which gives hash special property (i.e. that it…

Bitcoin- I was skeptical hearing this word. But when I understood the cryptography behind I realized that this is a quiet revolution in IT. Let’s dig into technical details today. But before going into crypto please imagine exchanging money on the tick with your friends and family. Sometimes you lend…

So how is your connection to the website secured? 4 elements constitute a cipher suite of the connections: - authentication certificate, - key exchange algorithm, - encryption algorithm, - hashing function. Firstly we need to know who we are talking with. For that, we need an authentication certificate that will…

How do you know that your bank account page is the right one? Maybe choosing the first page from google will be the safest choice? But what if your google is not google itself? Hmmm… The above question could be bothering but fortunately, we have already figured out some solution…

How can we be sure that a digitally signed document is indeed from the right person? To understand that let’s see how it works. So to make a digital signature you need: - asymmetric key pair — two keys, 1st secret which can only encrypt, 2nd public which can only decrypt …

We are slowly getting to a point where you will understand how secure connections are established on the internet. But before that let’s understand one more thing. If you saw my post regarding the Diffie-Helman key exchange you might be wondering: what if someone in the middle would intercept the…

When I was a newbie in the secure communication world, the one thing which bothered me, was how to securely exchange the secret through the internet. I didn’t understand how is it possible to exchange information publically and not enable anyone else to generate the same secretkey. …

Let’s find out what it means to break the cipher. Someone may believe that the knowledge of how the cipher would be enough. However, in most cases, the algorithm is well known, but the goal is to find a secret key. And how to do that? You can: - check…

That’s a valid question since this standard is so popular. Firstly let’s look at the key space and compare the time of cracking it by brute force method (by checking every possible key). - For One Time Pad cipher, key length is equal to the length of plain text i.e…