hmac

New to JS, I'm also learning to use crypto libraries. I don't understand why signing/encoding the same message with the same secret yields differing results. I'm using jsSHA 1.3.1 found here , and CryptoJS 3.0.2 described here trying to create a base64 sha-1 encoded hmac signature. Here's the code: In html... <script src="lib/jsSHA/src/sha1.js"></script> <script src="http://crypto-js.googlecode.com/svn/tags/3.0.2/build/rollups/hmac-sha1.js"></script> And in js... var message = "shah me"; var secret = "hide me"; var crypto = CryptoJS.HmacSHA1(message, secret).toString(CryptoJS.enc.Base64) + '='

Is the security of the HMAC based on SHA-1 affected by the collisions attacks on SHA-1? Nick Johnson The security implications of HMAC are described in detail in the security section of the RFC . In a nutshell, a very strong attack indeed is required before the security of the HMAC is threatened; the existing collision attacks on SHA-1 certainly don't constitute such. HMAC is specifically designed to make attacks difficult, and ordinary collision attacks won't generally suffice: The security of the message authentication mechanism presented here depends on cryptographic properties of the hash

Facebook requires that I create a appsecret_proof: https://developers.facebook.com/docs/graph-api/securing-requests And I have done this using the following code: public string FaceBookSecret(string content, string key) { var encoding = new System.Text.ASCIIEncoding(); byte[] keyByte = encoding.GetBytes(key); byte[] messageBytes = encoding.GetBytes(content); using (var hmacsha256 = new HMACSHA256(keyByte)) { byte[] hashmessage = hmacsha256.ComputeHash(messageBytes); return Convert.ToBase64String(hashmessage); } } Everything looks fine for me, however facebook says that the appsecret_proof is

I can make an HMAC using the following: var encrypt = crypto.createHmac("SHA256", secret).update(string).digest('base64'); I am trying to decrypt an encoded HMAC with the secret: var decrypt = crypto.createDecipher("SHA256", secret).update(string).final("ascii"); The following was unsuccessful. How can I decrypt a HMAC with the key? I get the following error: node-crypto : Unknown cipher SHA256 crypto.js:155 return (new Decipher).init(cipher, password); ^ Error: DecipherInit error HMAC is a MAC/keyed hash, not a cipher. It's not designed to be decrypted. If you want to encrypt something, use a

I am making an application that stores documents and gives each one a UID based on a SHA1 digest of a few things including the timestamp. The digest has a lot of characters, and I want to allow users to identify the documents by using the first x characters of the full digest. What's a good value for x if the number of documents is maybe around 10K - 100K? bdonlan Adapting the formulas on on wikipedia for the Birthday problem , you can approximate the probability of collision as e^(-n^2/(2^(b+1))) , where n is the document count and b is the number of bits. Graphing this formula with n=100,000

目录 time模块 datetime模块 random模块 os模块 sys模块 json模块 pickle模块 hashlib模块 hash是什么 撞库破解hash算法加密 hmac模块 logging模块 time模块 打印时间戳、格式化时间、结构化时间，总而言之就是打印不同类型的时间，进行不同类型时间的转换 import time # 时间戳 time.time() （*****） # 格式化时间 time.strftime('%Y-%m-%d %X') # 结构化时间 time.localtime() # 北京时间 time.gmtime() # 格林威治时间 time.gmtime(0) # 1970/1/1/0：00 # 时间的转换（了解中的了解） # 结构化时间转换为时间戳 now = time.localtime() time.mktime(now) # 结构化时间转格式化时间 time.strftime('%Y-%m-%d %X', now) # 2019-06-11 08:45:30 time.strftime('%Y-%m-%d', now) # 2019-06-11 # 格式化时间转结构化时间 now = time.strftime('%Y-%m-%d %X') time.strptime(now,'%Y-%m-%d %X') time.strptime(

I borrowed the HMAC-SHA1 Java code from http://tools.ietf.org/html/rfc6238 and adapted slightly to hardcode it to use one known key/message pair with known output. I then tried to write the same code in Python to verify the results, however I'm getting different values in Python and Java. The Java values are known to be good. Java code: import java.lang.reflect.UndeclaredThrowableException; import java.security.GeneralSecurityException; import java.text.DateFormat; import java.text.SimpleDateFormat; import java.util.Date; import javax.crypto.Mac; import javax.crypto.spec.SecretKeySpec; import