How to resolve the algorithm Bitcoin/address validation step by step in the Mathematica / Wolfram Language programming language
How to resolve the algorithm Bitcoin/address validation step by step in the Mathematica / Wolfram Language programming language
Table of Contents
Problem Statement
Write a program that takes a bitcoin address as argument, and checks whether or not this address is valid. A bitcoin address uses a base58 encoding, which uses an alphabet of the characters 0 .. 9, A ..Z, a .. z, but without the four characters:
With this encoding, a bitcoin address encodes 25 bytes:
To check the bitcoin address, you must read the first twenty-one bytes, compute the checksum, and check that it corresponds to the last four bytes. The program can either return a boolean value or throw an exception when not valid. You can use a digest library for SHA-256.
It doesn't belong to anyone and is part of the test suite of the bitcoin software.
You can change a few characters in this string and check that it'll fail the test.
Let's start with the solution:
Step by Step solution about How to resolve the algorithm Bitcoin/address validation step by step in the Mathematica / Wolfram Language programming language
Purpose: The provided Wolfram code is an implementation of a hashing algorithm for converting an input string into a 32-byte hashed value. It operates on the principle of converting an input string to a sequence of integers, hashing that sequence twice using SHA256, and extracting the first 32 bytes of the double-hashed result as the final hash.
Detailed Explanation:
Step 1: Character Conversion
- The
chars
variable contains a string of characters from '1' to 'z' (excluding 'I', 'l', and 'O'). - For each character in the input string, the
StringPosition
function finds its position in thechars
string. - The position is decremented by 1 to produce an integer value between 0 and 61.
Step 2: Integer Digits
- The list of integer values generated in Step 1 is converted to a base-58 integer using
IntegerDigits
.
Step 3: First Hash
- The base-58 integer is converted back to a string using
FromDigits
. - The resulting string is hashed using the SHA256 algorithm with a 256-bit output size.
Step 4: Second Hash
- The first 32-bit (4-byte) portion of the first hash is converted to a string.
- The string is hashed again using SHA256.
Step 5: Final Hash
- The first 32-bit portion of the second hash is extracted. This is the final hash result.
Step 6: Comparison
- The final 32-bit hash result is compared to the 32-bit hash calculated from the first 32-bit portion of the first hash. They should be equal if the algorithm is working correctly.
Note:
- The purpose of excluding 'I', 'l', and 'O' in the
chars
string is to avoid confusion with '1', '0', and 'l' in the output string. - The choice of a base-58 integer representation is arbitrary and could be replaced with other base representations.
- The use of double hashing with SHA256 is for increased security by reducing the likelihood of hash collisions.
Source code in the wolfram programming language
chars = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"; data =
IntegerDigits[
FromDigits[
StringPosition[chars, #][[1]] - 1 & /@ Characters[InputString[]],
58], 256, 25];
data[[-4 ;;]] ==
IntegerDigits[
Hash[FromCharacterCode[
IntegerDigits[Hash[FromCharacterCode[data[[;; -5]]], "SHA256"],
256, 32]], "SHA256"], 256, 32][[;; 4]]
You may also check:How to resolve the algorithm Peaceful chess queen armies step by step in the C programming language
You may also check:How to resolve the algorithm Formatted numeric output step by step in the PL/I programming language
You may also check:How to resolve the algorithm Colour bars/Display step by step in the Icon and Unicon programming language
You may also check:How to resolve the algorithm Higher-order functions step by step in the DWScript programming language
You may also check:How to resolve the algorithm Null object step by step in the 8th programming language