Encryption and Decryption of String according to given technique
Given a string S, the task is to encrypt the string and decrypt the string again to the original form.
Encryption Technique: If L is the length of the string, then take two values, one the ceil of √L (say b), and the other floor of √L (say a), and make a two-dimensional matrix having rows = a, and columns = b.
If rows*columns < L, then increase the value of a or b, whichever is minimum. Fill the matrix with the characters of the original string sequentially. After obtaining the matrix, read the matrix column-wise and print the obtained string.
Decryption Technique: If L is the length of the encrypted string, then again find the two values a and b, where a is the ceil value of the √L and b is the floor value of the √L. Similarly create a 2D Matrix in which store the string column wise and read the matrix row-wise to get the string in the original form.
Encryption Approach:
- Find the length L of the string.
- Find the ceil and floor values of √Length and assign them to the variables.
- Check if the product of the two variables >= Length, if not then increment the variable having lesser value by 1.
- Create a 2D matrix and fill the characters of the string row-wise.
- Read the matrix column-wise to get the encrypted string.
Decryption Approach:
- Find the length L of the string.
- Find the ceil and floor values of √Length and assign them to the variables.
- Create a 2D matrix and fill the matrix by characters of string column-wise.
- Read the matrix row-wise to get the decrypted string.
Below is the implementation of the above approach:
C++
// C++ implementation for Custom // Encryption and Decryption of String #include <bits/stdc++.h> using namespace std; // Function to encrypt the string string encryption(string s) { int l = s.length(); int b = ceil(sqrt(l)); int a = floor(sqrt(l)); string encrypted; if (b * a < l) { if (min(b, a) == b) { b = b + 1; } else { a = a + 1; } } // Matrix to generate the // Encrypted String char arr[a][b]; memset(arr, ' ', sizeof(arr)); int k = 0; // Fill the matrix row-wise for (int j = 0; j < a; j++) { for (int i = 0; i < b; i++) { if (k < l){ arr[j][i] = s[k]; } k++; } } // Loop to generate // encrypted string for (int j = 0; j < b; j++) { for (int i = 0; i < a; i++) { encrypted = encrypted + arr[i][j]; } } return encrypted; } // Function to decrypt the string string decryption(string s){ int l = s.length(); int b = ceil(sqrt(l)); int a = floor(sqrt(l)); string decrypted; // Matrix to generate the // Encrypted String char arr[a][b]; memset(arr, ' ', sizeof(arr)); int k = 0; // Fill the matrix column-wise for (int j = 0; j < b; j++) { for (int i = 0; i < a; i++) { if (k < l){ arr[j][i] = s[k]; } k++; } } // Loop to generate // decrypted string for (int j = 0; j < a; j++) { for (int i = 0; i < b; i++) { decrypted = decrypted + arr[i][j]; } } return decrypted; } // Driver Code int main() { string s = "Geeks For Geeks"; string encrypted; string decrypted; // Encryption of String encrypted = encryption(s); cout << encrypted << endl; // Decryption of String decrypted = decryption(encrypted); cout << decrypted; return 0; } |
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Java
// Java implementation for Custom // Encryption and Decryption of String class GFG { // Function to encrypt the String static String encryption(char[] s) { int l = s.length; int b = (int) Math.ceil(Math.sqrt(l)); int a = (int) Math.floor(Math.sqrt(l)); String encrypted = ""; if (b * a < l) { if (Math.min(b, a) == b) { b = b + 1; } else { a = a + 1; } } // Matrix to generate the // Encrypted String char [][]arr = new char[a][b]; int k = 0; // Fill the matrix row-wise for (int j = 0; j < a; j++) { for (int i = 0; i < b; i++) { if (k < l) { arr[j][i] = s[k]; } k++; } } // Loop to generate // encrypted String for (int j = 0; j < b; j++) { for (int i = 0; i < a; i++) { encrypted = encrypted + arr[i][j]; } } return encrypted; } // Function to decrypt the String static String decryption(char []s) { int l = s.length; int b = (int) Math.ceil(Math.sqrt(l)); int a = (int) Math.floor(Math.sqrt(l)); String decrypted=""; // Matrix to generate the // Encrypted String char [][]arr = new char[a][b]; int k = 0; // Fill the matrix column-wise for (int j = 0; j < b; j++) { for (int i = 0; i < a; i++) { if (k < l) { arr[j][i] = s[k]; } k++; } } // Loop to generate // decrypted String for (int j = 0; j < a; j++) { for (int i = 0; i < b; i++) { decrypted = decrypted + arr[i][j]; } } return decrypted; } // Driver Code public static void main(String[] args) { String s = "Geeks For Geeks"; String encrypted; String decrypted; // Encryption of String encrypted = encryption(s.toCharArray()); System.out.print(encrypted +"\n"); // Decryption of String decrypted = decryption(encrypted.toCharArray()); System.out.print(decrypted); } } // This code is contributed by PrinciRaj1992 |
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Python3
# Python3 implementation for Custom # Encryption and Decryption of String from math import ceil,floor,sqrt # Function to encrypt the def encryption(s): l = len(s) b = ceil(sqrt(l)) a = floor(sqrt(l)) encrypted="" if (b * a < l): if (min(b, a) == b): b = b + 1 else: a = a + 1 # Matrix to generate the # Encrypted String arr = [[' ' for i in range(a)] for j in range(b)] k = 0 # Fill the matrix row-wise for j in range(a): for i in range(b): if (k < l): arr[j][i] = s[k] k += 1 # Loop to generate # encrypted for j in range(b): for i in range(a): encrypted = encrypted + arr[i][j] return encrypted # Function to decrypt the def decryption(s): l = len(s) b = ceil(sqrt(l)) a = floor(sqrt(l)) decrypted="" # Matrix to generate the # Encrypted String arr = [[' ' for i in range(a)] for j in range(b)] k = 0 # Fill the matrix column-wise for j in range(b): for i in range(a): if (k < l): arr[j][i] = s[k] k += 1 # Loop to generate # decrypted for j in range(a): for i in range(b): decrypted = decrypted + arr[i][j] return decrypted # Driver Code s = "Geeks For Geeks"encrypted="" decrypted="" # Encryption of String encrypted = encryption(s) print(encrypted) # Decryption of String decrypted = decryption(encrypted) print(decrypted) # This code is contributed by mohit kumar 29 |
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C#
// C# implementation for Custom // Encryption and Decryption of String using System; class GFG { // Function to encrypt the String static String encryption(char[] s) { int l = s.Length; int b = (int) Math.Ceiling(Math.Sqrt(l)); int a = (int) Math.Floor(Math.Sqrt(l)); String encrypted = ""; if (b * a < l) { if (Math.Min(b, a) == b) { b = b + 1; } else { a = a + 1; } } // Matrix to generate the // Encrypted String char [,]arr = new char[a, b]; int k = 0; // Fill the matrix row-wise for (int j = 0; j < a; j++) { for (int i = 0; i < b; i++) { if (k < l) { arr[j, i] = s[k]; } k++; } } // Loop to generate // encrypted String for (int j = 0; j < b; j++) { for (int i = 0; i < a; i++) { encrypted = encrypted + arr[i, j]; } } return encrypted; } // Function to decrypt the String static String decryption(char []s) { int l = s.Length; int b = (int) Math.Ceiling(Math.Sqrt(l)); int a = (int) Math.Floor(Math.Sqrt(l)); String decrypted=""; // Matrix to generate the // Encrypted String char [,]arr = new char[a, b]; int k = 0; // Fill the matrix column-wise for (int j = 0; j < b; j++) { for (int i = 0; i < a; i++) { if (k < l) { arr[j, i] = s[k]; } k++; } } // Loop to generate // decrypted String for (int j = 0; j < a; j++) { for (int i = 0; i < b; i++) { decrypted = decrypted + arr[i, j]; } } return decrypted; } // Driver Code public static void Main(String[] args) { String s = "Geeks For Geeks"; String encrypted; String decrypted; // Encryption of String encrypted = encryption(s.ToCharArray()); Console.Write(encrypted +"\n"); // Decryption of String decrypted = decryption(encrypted.ToCharArray()); Console.Write(decrypted); } } // This code is contributed by PrinciRaj1992 |
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Output:
Gsree keFGskoe Geeks For Geeks
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