diff --git a/src/main/java/com/github/javafaker/Crypto.java b/src/main/java/com/github/javafaker/Crypto.java
index 2f53d8dd..e0b86184 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 285e81cd..c35f2049 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"));
     }
 }