Recall that the value of the block reward in Bitcoin halves after every 210.000 blocks added to the blockchain. Assume that that on average it takes about 5 minutes to add a new block How many blocks are expected to be added in one day? How many blocks are expected to be added in one year? After approximately how many years is the block reward halved?

Recall that the value of the block reward in Bitcoin halves after every 210.000 blocks added to the blockchain. Assume that that on average it takes about 5 minutes to add a new block How many blocks are expected to be added in one day? How many blocks are expected to be added in one year? After approximately how many years is the block reward halved?

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

See similar textbooks

Similar questions

1. Suppose that a symmetric cryptosystem with a 32-bit key length is used to encrypt messages written in English and encoded in ASCII. Given that keys are short, an attacker is using a brute-force exhaustive search method to decrypt a ciphertext of t bytes. Estimate the probability of uniquely recovering the plaintext corresponding to the ciphertext for the following values of t: 8, 64, 512. 2. Suppose that you are a computer virus writer; hence, you know that you need to store a copy of the code for your virus inside the virus itself. Moreover, suppose you know that a security administrator is also aware of this fact and will be using it to detect the presence of your virus in operating systems files. Explain how you can hide the embedded copy of your virus so that it is difficult for the security administrator to find it.
Many forms of cryptography are based on the following discrete log problem. Choose a cyclic group G (produced by one generator g) with finitely many elements. Alice and Bob want to set up a secret communication and need a secret key for that, which becomes a group element from G. They set up the following exchange (the so-called Diffie-Hellman protocol): 1. Alice chooses a secret group element a and sends unsecured g^a to Bob 2.Bob chooses a secret group element b and sends unsecured g^b to Alice 3. Alice calculates (g^b )^a and keeps this group element secret 4.Bob calculates (g^a )^b and keeps this group element secret Since a cyclic group is abelian, Alice and Bob now share the secret key (g^b )^a=(g^a )^b. The blue group elements are publicly known, the red elements are secret. The discrete log problem presented to an eavesdropper is computing say a from the publicly known data G,g,g^a. The naming of the problem comes from the solution a= glog⁡(ga ) which is generally difficult to…
Jenifer and Ted use symmetric-key cryptography for communicating confidentially. As there is no secure channel available for sending the secret key, they use Diffie-Hellman Key Agreement protocol to agree upon a secret key K. They select a prime p=2357, generator g=123 which are public. Jenifer selects a secret j = 1001, Ted selects a secret t = 1003, and they can generate the shared secret key K. But Darth intercepts the Jenifer-Ted communication channel. Find the keys generated by Darth to plan an MITM attack between Jenifer and Ted if he selects a random secret d= 1002.
In this problem we explore the relationship between password length and cryptographic security. Suppose a password consists of 77 ASCII characters. You can review the ASCII characters here.. Exactly 27=12827=128 of these codes are for printable characters; we will assume every character in the password is printable. What is the size of the keyspace that consists of passwords of this form?What is the equivalent key length in bits? Assuming that you could check one password every 10−810−8 seconds, what is the worst case running time for cracking this password by brute force search (in days)? Now assume that the user used only 3131 characters from the keyboard. What is the key length in bits in this case? How many days, in the worst case, would it take to break this weaker password? You can't round to the nearest day here -- be as exact as possible. Supposing you used only 3131 characters, how long is the shortest password that achieves 252252 bits of security?
In order to investigate a serious cyber security fraud affecting all Estonian residents, we need to generate and test all in principle possible potential personal identification codes of all Estonian residents. We must certainly do it in such a way that it would certainly cover all currently living residents of Estonia. Estonian personal identification code (for example 38506301653) is formed as follows: - first digit (3) indicates both the gender and birth century; - second and third digits (85) represent the last two digits of birth year (1985); - fourth and fifth digits (06) represent the month of birth (June); - sixth and seventh digits (30) represent the date of birth (30); - eighth, ninth and tenth digits (165) simply represent the sequence number (the combination 000 is not used); - eleventh digit (3) is an error correction code calculated from the previous ten digits according to a certain deterministic algorithm. We've prepared a small test serie and we know that it takes 1…
Use the RSA cipher with public key n = 713 = 23 · 31 and e = 43 to decrypt the ciphertext 675 089 089 048 and find the original messages. Consider d=307 and Performs all steps show all the step on how you solved it use pencil and paper. dont use AI
In this problem we explore the relationship between password length and cryptographic security. Suppose a password consists of 6 ASCII characters. You can review the ASCII characters here.. There are exactly 2' = 128 ASCII characters; we will assume every character in the password is ASCII (non-printing characters are allowed). What is the size of the keyspace that consists of passwords of this form? What is the equivalent key length in bits? Assuming that you could check one password every 10-" seconds, what is the worst case running time for cracking this password by brute force search (in days)?| Now assume that the user used only 28 characters from the keyboard. What is the key length in bits in this case? How many days, in the worst case, would it take to break this weaker password? You can't round to the nearest day here be as exact as possible. Supposing you used only 28 characters, how long is the shortest password that achieves 248 bits of security?
Alice and Bod have decided to use a symmetric encryption algorithm. They have some assumptions about their messages:- Messages only contain capital letters (i.e. A to Z)- The length of their shared key must be greater than or equal to the length of the plaintext- They assign each letter a number as follows: (A,0), (B,1), (C,2), (D,3),…, (Z,25)Their algorithm combines the key and the message using modular addition. The numerical values of corresponding message and key letters are added together, modulo 26. For example, if the plain text is “HELLO” and the key is “SECRET” then the encrypted message is calculated as following:Since the length of the plaintext is 5, we just need the first 5 letters of the key (i.e. “SECRE”), then for each letter, we should add corresponding letters in both the plaintext and the key modulo 26.Plaintext: H (7) E (4) L (11) L (11) O (14)Key: S (18) E (4) C (2) R (17) E(4)Cipher: Z (25) I (8) N(13) C(2) S (18) Write a program in Python, C/C++ or JavaScript to…
Use a coding matrix A of your choice. Use a graphing utility to find the multiplicative inverse of your coding matrix. Write a cryptogram for each message. C perform all necessary matrix multiplications. DGE OU T AHEAD BR 2 18 4 75 0 15 21 20 0 1 8 5 1 4 .... 1 1 -12 32 -15 Using the coding matrix the coded message is.····☐☐☐☐☐☐☐☐☐☐ 2 2 1 5 4 4 4 7 (Simplify your answers.) 61