RSATest.java

packagecom.thealgorithms.ciphers;

importstaticorg.junit.jupiter.api.Assertions.assertEquals;
importstaticorg.junit.jupiter.api.Assertions.assertThrows;

importjava.math.BigInteger;
importorg.junit.jupiter.api.Test;

classRSATest {

privatefinalRSArsa = newRSA(1024);

@Test
voidtestEncryptDecryptString() {
StringoriginalMessage = "Such secure";
StringencryptedMessage = rsa.encrypt(originalMessage);
StringdecryptedMessage = rsa.decrypt(encryptedMessage);
assertEquals(originalMessage, decryptedMessage);
 }

@Test
voidtestEncryptDecryptBigInteger() {
BigIntegeroriginalMessage = newBigInteger("12345678901234567890");
BigIntegerencryptedMessage = rsa.encrypt(originalMessage);
BigIntegerdecryptedMessage = rsa.decrypt(encryptedMessage);
assertEquals(originalMessage, decryptedMessage);
 }

@Test
voidtestEmptyMessage() {
StringoriginalMessage = "";
assertThrows(IllegalArgumentException.class, () -> rsa.encrypt(originalMessage));
assertThrows(IllegalArgumentException.class, () -> rsa.decrypt(originalMessage));
 }

@Test
voidtestDifferentKeySizes() {
// Testing with 512-bit RSA keys
RSAsmallRSA = newRSA(512);
StringoriginalMessage = "Test with smaller key";

StringencryptedMessage = smallRSA.encrypt(originalMessage);
StringdecryptedMessage = smallRSA.decrypt(encryptedMessage);

assertEquals(originalMessage, decryptedMessage);

// Testing with 2048-bit RSA keys
RSAlargeRSA = newRSA(2048);
StringlargeOriginalMessage = "Test with larger key";

StringlargeEncryptedMessage = largeRSA.encrypt(largeOriginalMessage);
StringlargeDecryptedMessage = largeRSA.decrypt(largeEncryptedMessage);

assertEquals(largeOriginalMessage, largeDecryptedMessage);
 }

@Test
voidtestSpecialCharacters() {
StringoriginalMessage = "Hello, RSA! @2024#";
StringencryptedMessage = rsa.encrypt(originalMessage);
StringdecryptedMessage = rsa.decrypt(encryptedMessage);
assertEquals(originalMessage, decryptedMessage);
 }
}