aes-gcm | 易学教程

decrypt TLS 1.2 AES-GCM packet

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问题 I'm working on a Java program to decrypt a TLS 1.2 Session which is using the TLS_RSA_WITH_AES_128_GCM_SHA256 cipher. I recorded a test session using wireshark. The Master Secret is known. No. Time Protocol Length Info 4 0.000124000 TLSv1.2 166 Client Hello 6 0.000202000 TLSv1.2 1074 Server Hello, Certificate, Server Hello Done 8 0.001071000 TLSv1.2 393 Client Key Exchange, Change Cipher Spec, Finished 9 0.003714000 TLSv1.2 301 New Session Ticket, Change Cipher Spec, Finished 11 6.443056000

Unable to set IV for aes gcm using openssl

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问题 I am trying to use AES GCM encryption mechanism provided by OpenSSL in C++ and using example on this link as reference: https://wiki.openssl.org/index.php/EVP_Authenticated_Encryption_and_Decryption However, following statement gives me error: /* Set IV length if default 12 bytes (96 bits) is not appropriate */ if(1 != EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_IVLEN, 16, NULL)) handleErrors(); The error that I get is: error: ‘EVP_CTRL_GCM_SET_IVLEN’ was not declared in this scope". I do not

How Can We Use GCM Mode Encryption in PHP?

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问题 I have been reading a lot about GCM and how awesome it is and I would like to know how could I use AES-GCM authenticated encryption using PHP . Is it supported in mcrypt() ? I found some references to GCM in the Codeigniter framework documentation which leads me to believe it is possible to use in Codeigniter. And I also came across something in a doc about Zend . I'm not looking to use a Codeigniter driver though as I don't use any framework and don't intend to for my current projects. It

Why is random IV fine for AES-CBC but not for AES-GCM

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问题 I have been using AES-CBC for encryption and I use a random IV each time I encrypt plain text. As far as I can tell, this is the recommended approach. I have been looking into AES-GCM / AES-CTR, primarily for the AEAD. I have not yet implemented anything with this but from everything I have read, basically the nonce is just a shorted IV and there is an internal counter that is used for each encryption call. The developer / needs to make sure the nonce changes before the 32 bit counter cycles

Late authentication in OpenSSL GCM decryption

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I am using OpenSSL's EVP interfaces to implement AES encryption using GCM mode. Now GCM, being one of the authentication modes, provides cipher text integrity. Meaning it generates a tag (MAC - message authentication code) on the cipher text (and additional data, if provided). This tag can later be checked before decryption, to ensure that the cipher text has not been modified. I have implemented the encryption as per this blog post: http://incog-izick.blogspot.in/2011/08/using-openssl-aes-gcm.html While decrypting I am using the following API calls (in that order): // setting cipher, key and

Cannot decrypt long AES-256 GCM message with Java

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问题 Related to this question: Cannot decrypt AES-256 GCM with Java The Java decrypt issue seems to only be fixed if the encrypted message is short, i.e. two words or so. I've tried with the words, "hello" and "short string", and both of these words were decrypted fine. When I tried something like, Alphanumeric string test1 with more numbers such as 5, 4, 3, 2, 1 AEADBadTagException came up again. EDIT: This issue is directly related to how long the encrypted message is. Two words is a bit of an

Cannot decrypt AES-256 GCM with Java

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问题 I have a node module that can both encrypt and decrypt with AES-256 GCM. Now I am also trying to decrypt with Java whatever the node module encrypts, but I keep getting a AEADBadTagException. I have tested the node module by itself and can confirm that it works as intended. I know that Java assumes the authentication tag is the last part of the message, so I ensured that the tag is the last thing appended in the node module. Right now I'm just testing with the word, "hello". This is the

AES 128 GCM objective C osx

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I am trying to encrypt/decrypt a string in an AES-128 GCM format in objective c. I have looked everywhere but can't seem to find a working solution. Enrique Not so long ago I had a similar problem and the best answer I could find was this one . To sum up, iOS has some functions to do what you want but they are private. So, until Apple decides to release these functions, I opted for developing my own library, currently stored in GitHub and available in CocoaPods . The case you describe could be implemented this way: #import <CommonCrypto/CommonCrypto.h> #import "IAGAesGcm.h" // For the case you

Tag mismatch error in AES-256-GCM Decryption using Java

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问题 I have the following function written in Javascript for encryption using aes-256-gcm: encrypt: function (text, masterkey){ try { // random initialization vector var iv = crypto.randomBytes(12); // random salt var salt = crypto.randomBytes(64); // derive key: 32 byte key length - in assumption the masterkey is a cryptographic and NOT a password there is no need for // a large number of iterations. It may can replaced by HKDF var key = crypto.pbkdf2Sync(masterkey, salt, 2145, 32, 'sha512'); //

AES-GCM: AEADBadTagException: mac check in GCM failed

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While trying to implement AES-GCM for the first time, we are facing issue in generating AuthenticationTag, Encrypted cipher & GCM mac check fails in the end. For out current implementation tag[] is being populated but byte[] encrypted remains empty. And because of this cipher.doFinal(data1, offset) gives ' mac check in GCM failed '. It appears to be some issue around the size of byte arrays, can someone please share on what basis should the output buffer size be determined? Should this be done in chunks? Any pointers/links to AES-GCM implementation will be highly appreciated. Following is our