We remark that AES-GCM-SIV is already integrated into Google's BoringSSL library \cite{BoringSSL}, and its deployment for ticket encryption in QUIC \cite{QUIC} is underway.
This memo specifies two authenticated encryption algorithms that are nonce misuse-resistant - that is that they do not fail catastrophically if a nonce is repeated.
For encryption, it is slower than AES-GCM, because achieving nonce-misuse resistance requires, by definition, two (serialized) passes over the data. Nevertheless, optimized implementations run GCM-SIV (for 128-bit keys) at less than one cycle per byte on modern processors (roughly 2/3 of the speed of nonce-respecting AES-GCM). On the other hand, GCM-SIV decryption runs at almost the same speed as AES-GCM.
FIPS 140-2 requires that one of its PRNGs be used (which they call DRBGs). In BoringCrypto, we use CTR-DRBG with AES-256 exclusively and RAND_bytes (the primary interface for the rest of the system to get random data) takes its output from there.
While these caching nodes are only used to temporarily store public media (imagine Telegram versions of superpopular YouTube hits), all data that goes through them is encrypted with a key unknown to the caching nodes. In other words, we treat these CDN caching nodes just like we treat your internet provider – they only ever get encrypted junk they can't decipher.
You simply enable encryption when you create a new table and DynamoDB takes care of the rest. Your data (tables, local secondary indexes, and global secondary indexes) will be encrypted using AES-256 and a service-default AWS Key Management Service (KMS) key.
The introduction of the processor instructions AES-NI and VPCLMULQDQ, that are designed for speeding up encryption, and their continual performance improvements through processor generations, has significantly reduced the costs of encryption overheads.
More and more applications and platforms encrypt all of their data and traffic. As an example, we note the world wide proliferation of the use of AES-GCM, with performance dropping down to 0.64 cycles per byte (from ~23 before the instructions), on the latest Intel processors.
The catalyst for the development of CCM mode was the submission of OCB mode for inclusion in the IEEE 802.11i standard. Opposition was voiced to the inclusion of OCB mode because of a pending patent application on the algorithm. Inclusion of a patented algorithm meant significant licensing complications for implementors of the standard.
In addition to symmetric key encryption using AES-256 keys, you can now create various types of asymmetric keys for decryption or signing operations, which means that you can now store your keys used for PKI or code signing in a Google Cloud managed keystore. Specifically, RSA 2048, RSA 3072, RSA 4096, EC P256, and EC P384 keys will be available for signing operations, while RSA 2048, RSA 3072, and RSA 4096 keys will also have the ability to decrypt blocks of data.
真正大量支援 IFMA 的是 2019 後的 Intel CPU 了，但到了去年推出的 Alder Lake 因為 E-core 不支援 AVX-512 的關係 (但 P-core 支援)，預設又關掉了。
所以如果問這個 bug 嚴不嚴重，當然是很嚴重，但影響範圍就有點微妙了。
接下來講第二個 CVE，是 AES OCB 的實做問題，比較有趣的地方是 Hacker News 上的討論引出了 Mosh 的作者跳出來說明，他居然提到他們在二月的時候試著換到 OpenSSL 的 AES OCB 時有測出這個 bug，被 test case 擋下來了：
Mosh uses AES-OCB (and has since 2011), and we found this bug when we tried to switch over to the OpenSSL implementation (away from our own ocb.cc taken from the original authors) and Launchpad ran it through our CI testsuite as part of the Mosh dev PPA build for i686 Ubuntu. (It wasn't caught by GitHub Actions because it only happens on 32-bit x86.) https://github.com/mobile-shell/mosh/issues/1174 for more.
So I would say (a) OCB is widely used, at least by the ~million Mosh users on various platforms, and (b) this episode somewhat reinforces my (perhaps overweight already) paranoia about depending on other people's code or the blast radius of even well-meaning pull requests. (We really wanted to switch over to the OpenSSL implementation rather than shipping our own, in part because ours was depending on some OpenSSL AES primitives that OpenSSL recently deprecated for external users.)
Maybe one lesson here is that many people believe in the benefits of unit tests for their own code, but we're not as thorough or experienced in writing acceptance tests for our dependencies.
Mosh got lucky this time that we had pretty good tests that exercised the library enough to find this bug, and we run them as part of the package build, but it's not that farfetched to imagine that we might have users on a platform that we don't build a package for (and therefore don't run our testsuite on).
The threat actor was also able to copy a backup of customer vault data from the encrypted storage container which is stored in a proprietary binary format that contains both unencrypted data, such as website URLs, as well as fully-encrypted sensitive fields such as website usernames and passwords, secure notes, and form-filled data.
Lots of vault entries may be encrypted with ECB mode AES-256. I worked on supporting unauthenticated CBC mode. But re-encrypting a users vault entries requires having their master key.
