sha1

I think I'm missing something. I was under the impression that git's usage of a SHA-1 hash commit identifier meant that one could be certain that patch obtained from someone else for that commit had not been altered. Take this test I did on my machine (name and email changed, obviously): cd dogcatcher dogcatcher> git log commit 926f347567a9da6f7692aca0e23d13f094d9e3a6 Author: Joe User <joe@test.com> Date: Sat Dec 17 15:28:55 2011 -0600 3rd branch commit commit 11e8055aa5e8f0d323c48b4f691adced7a8a9762 Author: Joe User <joe@test.com> Date: Sat Dec 17 15:10:44 2011 -0600 second branch commit

　　用户注册 1. 对账号密码进行加盐加密 加盐：两个用户密码相同，那么他们密码的哈希值也是相同的。我们可以通过“随机化”哈希来阻止这类攻击，于是当相同的密码被哈希两次之后，得到的值就不相同了。我们在密码中加入一段随机的字符来进行加密，这样每次生成的密文都是不同的，这个字符串就是盐（salt），我们把密文和盐值存入数据库中。 校验密码的步骤 从数据库取出用户的密码哈希值和对应盐值 将盐值混入用户输入的密码，并且使用同样的哈希函数进行加密 比较上一步的结果和数据库储存的哈希值是否相同，如果相同那么密码正确，反之密码错误 1 // 需要注册的账号密码 2 　　　　 String account = "zhangsan"; 3 String pwd = "zaqxsw000"; 4 byte[] saltByte = Digests.generateSalt(Constants.SALT_SIZE); 5 // 生成的盐 6 String saltStr = Encodes.encodeHex(saltByte); 7 System.out.println(saltStr); 8 9 byte[] hashPassword = Digests.sha1(pwd.getBytes(), saltByte, Constants.HASH_INTERATIONS); 10 String

Is it possible to decrypt some string which was earlier encrypted with the SHA-1 algorithm in Java? Brendan Long SHA1 is a cryptographic hash function , and the entire point is that you can't undo it. If it was possible to reverse the hash (find the input for a given hash), it wouldn't be useful. If you need to encrypt something and later decrypt it, you should use an encryption function like AES or RSA . However, for very simple inputs it may be possible to crack the hash function by guessing what the input was and checking if the hash is the same. Example Python code: def crack_hash(hash_to

在C#中，数据的Hash以MD5或SHA-1的方式实现，MD5与SHA1都是Hash算法，MD5输出是128位的，SHA1输出是160位的，MD5比SHA1快，SHA1比MD5强度高。 MD5与SHA1的比较： 　　1）对强行攻击的安全性：最显著和最重要的区别是SHA-1摘要比MD5摘要长32 位。使用强行技术，产生任何一个报文使其摘要等于给定报摘要的难度对MD5是2^128数量级的操作，而对SHA-1则是2^160数量级的操作。这样，SHA-1对强行攻击有更大的强度。 　　2）对密码分析的安全性：由于MD5的设计，易受密码分析的攻击，SHA-1显得不易受这样的攻击。 　　3）速度：在相同的硬件上，SHA-1的运行速度比MD5慢。 SHA-1和MD5在C#中的实现： 1 public class HashHelper 2 { 3 /// <summary> 4 /// 计算文件的 MD5 值 5 /// </summary> 6 /// <param name="fileName">要计算 MD5 值的文件名和路径</param> 7 /// <returns>MD5 值16进制字符串</returns> 8 public static string MD5File(string fileName) 9 { 10 return HashFile(fileName, "md5");

I have generated my SHA1 code from my keystore but when I try to create an OAuth client 2.0, Google game console is giving me the error: "Certificate fingerprint is invalid". Anyone knows why this happens? How do I fix this? I've contacted Google Play Developer Support about this issue (I've got a same problem). Here is their answer : Please ensure the key is set to 2048 bit and is valid for at least 25 years. I've tried it, but sadly my debug.keystore is still not getting accepted, maybe there will be some luck on your side. $ keytool -genkey -v -keystore debug.keystore -storepass android

I am trying to figure out how to read multiple digests (md5, sha1, gpg) based on the same InputStream using DigestInputStream . From what I've checked in the documentation, it seems to be possible by cloning the digest. Could somebody please illustrate this? I don't want to be re-reading the stream in order to calculate the checksums. Louis Wasserman You could wrap a DigestInputStream around a DigestInputStream and so on recursively: DigestInputStream shaStream = new DigestInputStream( inStream, MessageDigest.getInstance("SHA-1")); DigestInputStream md5Stream = new DigestInputStream( shaStream

If I have a file that I want to monitor for any changes (other than looking at the file date stamps etc). How could I perform a SHA1 hash on its contents? I think this is what GIT does, so I just want to learn how to do it kd7 using (FileStream stream = File.OpenRead(@"C:\File.ext")) { using (SHA1Managed sha = new SHA1Managed()) { byte[] checksum = sha.ComputeHash(stream); string sendCheckSum = BitConverter.ToString(checksum) .Replace("-", string.Empty); } } Calculate the checksum periodically. For the specific application that you described, finding the SHA-1 hash of each file in the