From e47bacc309f04437072750f75da162f3ce4ec1aa Mon Sep 17 00:00:00 2001
From: Michal Gutowski <michal@cucumbersome.net>
Date: Thu, 15 Sep 2022 15:32:27 +0200
Subject: [PATCH] Make sure that padding is used

In some cases it's possible to have MD5 hash (and possibly other as well) with the first byte set to 0. In this case it gets removed, while converting to BigInteger and the hex string has 31 characters. To make sure that it works as expected, we need to guarantee proper padding.
---
 src/main/java/com/github/javafaker/Crypto.java     | 12 ++++++------
 src/test/java/com/github/javafaker/CryptoTest.java |  8 ++++----
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/src/main/java/com/github/javafaker/Crypto.java b/src/main/java/com/github/javafaker/Crypto.java
index 2f53d8ddc..e0b861844 100644
--- a/src/main/java/com/github/javafaker/Crypto.java
+++ b/src/main/java/com/github/javafaker/Crypto.java
@@ -12,27 +12,27 @@ protected Crypto(Faker faker) {
     }
 
     public String md5() {
-        return generateString("MD5");
+        return generateString("MD5", "%032x");
     }
 
     public String sha1() {
-        return generateString("SHA-1");
+        return generateString("SHA-1", "%040x");
     }
 
     public String sha256() {
-        return generateString("SHA-256");
+        return generateString("SHA-256", "%064x");
     }
 
     public String sha512() {
-        return generateString("SHA-512");
+        return generateString("SHA-512", "%0128x");
     }
 
-    private String generateString(String algorithm) {
+    private String generateString(String algorithm, String format) {
         try {
             MessageDigest messageDigest = MessageDigest.getInstance(algorithm);
             String characters = faker.lorem().characters();
             messageDigest.update(characters.getBytes(), 0, characters.length());
-            return new BigInteger(1, messageDigest.digest()).toString(16);
+            return String.format(format, new BigInteger(1, messageDigest.digest()));
         } catch (NoSuchAlgorithmException noSuchAlgorithmException) {
             throw new RuntimeException(noSuchAlgorithmException);
         }
diff --git a/src/test/java/com/github/javafaker/CryptoTest.java b/src/test/java/com/github/javafaker/CryptoTest.java
index 285e81cdb..c35f20497 100644
--- a/src/test/java/com/github/javafaker/CryptoTest.java
+++ b/src/test/java/com/github/javafaker/CryptoTest.java
@@ -10,21 +10,21 @@ public class CryptoTest extends AbstractFakerTest {
 
     @Test
     public void testMd5() {
-        assertThat(faker.crypto().md5(), matchesRegularExpression("[a-z\\d]+"));
+        assertThat(faker.crypto().md5(), matchesRegularExpression("\\b[a-fA-F\\d]{32}\\b"));
     }
 
     @Test
     public void testSha1() {
-        assertThat(faker.crypto().sha1(), matchesRegularExpression("[a-z\\d]+"));
+        assertThat(faker.crypto().sha1(), matchesRegularExpression("\\b[a-fA-F\\d]{40}\\b"));
     }
 
     @Test
     public void testSha256() {
-        assertThat(faker.crypto().sha256(), matchesRegularExpression("[a-z\\d]+"));
+        assertThat(faker.crypto().sha256(), matchesRegularExpression("\\b[a-fA-F\\d]{64}\\b"));
     }
 
     @Test
     public void testSha512() {
-        assertThat(faker.crypto().sha512(), matchesRegularExpression("[a-z\\d]+"));
+        assertThat(faker.crypto().sha512(), matchesRegularExpression("\\b[a-fA-F\\d]{128}\\b"));
     }
 }