BAEL-1489: Introducing Red13PasswordEncoder

Something to nether use, but explain the idea of delegation and prefixing.

spring-5-security/src/main/java/com/baeldung/passwordstorage/Rot13PasswordEncoder.java

@@ -0,0 +1,30 @@
+package com.baeldung.passwordstorage;
+
+import org.springframework.security.crypto.password.PasswordEncoder;
+
+/**
+ * DISCLAIMER: Never ever use this in any production environment!
+ * <p>
+ * Does only work for characters.
+ */
+public class Rot13PasswordEncoder implements PasswordEncoder {
+
+	@Override
+	public String encode(CharSequence rawPassword) {
+		StringBuffer result = new StringBuffer(rawPassword.length());
+		rawPassword.chars().forEach(charCode -> {
+			if (charCode >= 65 && charCode <= 77 || charCode >= 97 && charCode <= 109) {
+				result.append(Character.toChars(charCode + 13));
+			} else if (charCode >= 78 && charCode <= 90 || charCode >= 110 && charCode <= 133) {
+				result.append(Character.toChars(charCode - 13));
+			}
+		});
+
+		return result.toString();
+	}
+
+	@Override
+	public boolean matches(CharSequence rawPassword, String encodedPassword) {
+		return encode(rawPassword).equals(encodedPassword);
+	}
+}

spring-5-security/src/test/java/com/baeldung/passwordstorage/Rot13PasswordEncoderTest.java

@@ -0,0 +1,36 @@
+package com.baeldung.passwordstorage;
+
+import org.junit.Test;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+
+public class Rot13PasswordEncoderTest {
+
+	private final Rot13PasswordEncoder encoder = new Rot13PasswordEncoder();
+
+	@Test
+	public void given_theEncodedPassword_should_returnTheClearTextPassword() {
+		String password = "baeldung";
+		String encoded = encoder.encode(password);
+		String actualResult = encoder.encode(encoded);
+
+		assertThat(actualResult, is(password));
+	}
+
+	@Test
+	public void given_correctPassword_should_returnTrue() {
+		String password = "baeldung";
+		String encoded = encoder.encode(password);
+		boolean actualResult = encoder.matches(password, encoded);
+
+		assertThat(actualResult, is(true));
+	}
+
+	@Test
+	public void given_incorrectPassword_should_returnFalse() {
+		boolean actualResult = encoder.matches("baeldung", "spring");
+
+		assertThat(actualResult, is(false));
+	}
+}