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AES CMAC Calculation C#

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问题 I know MAC is 4 first byte of last block encryption, and found this CMAC explanation here but it's kinda hard to understand. And maybe there are already some CMAC AES questions but I'm sorry I can't understand it well. Anyone can explain how to calculate CMAC? and if necessary with some example code in C#. Thanks 回答1: First you need to derive two subkeys from your AES key. The algorithm is described well in RFC4493, but I will include some code samples here for reference. For this, you will

How to decrypt aes-256-cbc in Java

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I have encrypted the string in php. Decrypted successfully from php and node.js. In addition, it must be decrypted by java. Help me an example of decrypting from java? PHP Encrypt code /* encrypt */ $encryption_method = 'aes-256-cbc'; $secretHash = "d95acd54c6a821ff32c52825b931c194"; $iv_size = openssl_cipher_iv_length($encryption_method); $iv = openssl_random_pseudo_bytes($iv_size); //encrypt $encryptedMessage = openssl_encrypt($new_token, $encryption_method, $secretHash, 0, $iv); //Concatenate iv with data $ciphertext = bin2hex($iv).$encryptedMessage; /* decrypt the cipher */ $iv_size =

Which AES library to use in Ruby/Python?

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I need to be able to send encrypted data between a Ruby client and a Python server (and vice versa) and have been having trouble with the ruby-aes gem/library. The library is very easy to use but we've been having trouble passing data between it and the pyCrypto AES library for Python. These libraries seem to be fine when they're the only one being used, but they don't seem to play well across language boundaries. Any ideas? Edit: We're doing the communication over SOAP and have also tried converting the binary data to base64 to no avail. Also, it's more that the encryption/decryption is

AES Encryption Golang and Python

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I am working on a fun side project for myself. A golang server and a python client. I want data transmitted to be encrypted but cant seem to get the two encryption schemes working together. I am a novice when it comes to encryption so please explain like you are talking to a toddler. Here is my golang encryption functions: import ( "crypto/aes" "crypto/cipher" "crypto/rand" "errors" "io" "fmt" ) func Encrypt(key, text []byte) (ciphertext []byte, err error) { var block cipher.Block if block, err = aes.NewCipher(key); err != nil { return nil, err } ciphertext = make([]byte, aes.BlockSize+len

Client server AES encryption

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问题 I am developing a client server application in which data is transferred between two clients through the server. The data should be encrypted and I thought of using AES. My thought was to use PBKDF2 in order to derive the AES key from the client's password. In this case the client will encode the data, the server will decode it, reencode it using the 2nd client's password and send it to the 2nd client. Do you think this is the best way to implement this? Is there a way for the first client to

How to use AES_ENCRYPT properly?

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问题 I'm trying to use AES encryption (AES_ENCRYPT in MySQL) for user passwords but I came up with a bunch of different problems. This is the SQL query that I use to store a new user into the database: INSERT INTO user VALUES ( '15', 'John', 'Doe', '123 Fake St.', AES_ENCRYPT('mypassword', 'mysalt'), 'mysalt' ) Where the salt would be a random string in a real case. It works fine. I mean, I'm able to retrieve the original password. In this example, AES_DECRYPT(user.password, 'mysalt') WHERE user

Java: Get rid of `Cipher.init()` overhead

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问题 I need to increase performance of the following method: private byte[] decrypt(final byte[] encrypted, final Key key) throws ... { this.cipher.init(Cipher.DECRYPT_MODE, key); return this.cipher.doFinal(encrypted); } The cipher object ("AES/ECB/NoPadding") is initialized in the constructor, so that it can be reused. ECB is used since the encrypted array will contain always only 16 bytes of data (i.e. 1 block of data). 128 bit key is used. This method is called millions of times to decrypt 16

Password Cracking in 2010 and Beyond

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问题 I have looked a bit into cryptography and related matters during the last couple of days and am pretty confused by now. I have a question about password strength and am hoping that someone can clear up my confusion by sharing how they think through the following questions. I am becoming obsessed about these things, but need to spend my time otherwise :-) Let's assume we have an eight-digit password that consists of upper and lower-case alphabetic characters, numbers and common symbols. This

Using SharpAESCrypt to encrypt strings

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I decided to use the SharpAESCrypt implementation of AES encryption in C#. According to their documentation ( https://www.aescrypt.com/sharp_aes_crypt.html ) you should be able to use a static method, providing a password string, plain-text input stream and a output stream. The data I get out of my output stream appears to be all zero's. I suspect I am doing something wrong converting strings to a stream and back. Can anyone see anything that is obviously wrong with the code below? (It compiles and runs, but the newByteArray is filled with 0's at the end) private void encryptMemStream() { byte

PHP AES Decryption working Encryption NOT

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So, I have 3 Pieces out of 4 working, iOS Encrypt-Decrypt from this Link And I am able to Decrypt the data Encrypted from iOS I am having trouble Encrypting on PHP side. When I do echo Encryption code. PHP prints something like F>HFl8aR what does it mean ? SALTKEY = 'a16byteslongkey!'; Decryption Code: Working $result = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, (SALTKEY . str_repeat(chr(0x00), 16)), base64_decode($text), 'ecb'); $pad_char = ord(substr($result, -1)); return substr($result, 0, strlen($result) - $pad_char); Encryption Code : Not Working $result = mcrypt_encrypt(MCRYPT_RIJNDAEL