2021年7月24日 · In CBC mode, the exclusive-or is plaintext against the previous ciphertext block, except for the first block, which uses a random IV. Does GCM do the same, or does it do the exclusive-or against something else? If so, can someone please briefly explain how GCM uses the IV and how the exclusive-or is done.

2022年7月21日 · However it seems slow so I decide to switch to AES GCM 256 bit key, 96 bit IV which has some parts I don't understand such as: Auth tag: the output of AES GCM when encrypting and decrypting needs it Can I prepend it to the encrypted cipher text so it's instantly available when decrypting? Or does it need to be hidden from attacker?

It happens that on the internet I often find that AES encryption should use a 128-bit key only if it is used in conjunction with the GCM mode of operation. Why only with 128-bit keys? What happen...

2013年10月4日 · For this reason, AES-GCM is not that much used for encryption of stored data, but rather data at transit. Summary GCM is a very good mode of operation, and it often is more convenient than legacy algorithms combinations like CBC + HMAC.

2013年3月27日 · We are using the encryption built into Solaris 11 ZFS, which offers the choice between CCM (CBC counter mode) and GCM (Galois counter mode). What are the pros and cons of choosing each of these cip...

GCM mode already incorporates any params that could affect the outcome of the decryption. The associated authenticated data is there to allow you to rely on context for your decryption. For example, say you are encrypting some records associated with a user. You may want to include the user's database ID as the authenticated data. If a user found a way to copy another user's data and key into ...

In the CBC mode the person who performs the encryption is the one who provides the IV for the encryption -- and the IV is required to decrypt the ciphertext. However, in GCM I read that the nonce value is internal -- so is it a value which needs to be kept tracked of by the person who encrypts / decrypts the values?

2018年8月7日 · GCM specification defines the initial counter value Y0 Y 0 for encryption/decryption operations as follows:

2022年12月13日 · AES-GCM uses CTR mode internally but adds authentication, which detects when someone modifies (tampers with) the ciphertext. It also supports authentication of associated data (e.g. file headers, a counter, other metadata). GCM is faster than doing CTR-then-HMAC or similar and saves people implementing that combination themselves.

There are several well-regarded block cipher modes for authenticated encryption which have made their way into standards and protocols: CCM, EAX, GCM, OCB, … If I am designing a new messaging or s...