Posts
What is the status of WhatsApp backups?
WhatsApp offered end-to-end encrypted backups in the past, which users could enable or disable: [https://faq.whatsapp.com/490592613091019/?cms\_platform=android](https://faq.whatsapp.com/490592613091019/?cms_platform=android) At present, there is a backup feature that's always turnned on, but if you follow those instructions, then you'll simply trigger a cleartext backup. Instead, the end-to-end encrypted backup option has moved and seems well …
Friend gave me a ciphertext + “key”, but nothing decrypts. What am I missing?
Crossposting from r/crypto101 — looking for more technical insights on possible AEAD/KDF formats.
cr.yp.to: 2025.11.23: NSA and IETF, part 4
cr.yp.to: 2025.11.23: NSA and IETF, part 3
cr.yp.to: 2025.11.23: NSA and IETF, part 2
Why isn't chacha20 NIST approved ?
It's quite odd that chacha20 is not approved by NIST, yet it's so widely used, even in TLS.. Why doesn't NIST acknowledge chacha20 ? Those NIST folks are a quite sketchy people
ChaCha20 for file encryption
Hi, assume I have an application, that already uses chacha20 for other purposes, Now some local state data is pretty sensitive so I encrypt it locally on disk. It is stored in one file, and that file can get quite large. I don't care about performance, my only concern is …
Modular exponentiation in RSA?
To keep the interim value from blowing up, rather than do MOD after EXP, can the EXP algorithm do a MOD at every internal step?
512 bit symmetric algorithms ?
Hi, Considering how Groover's algorithm would essentially cut the possibilities of any key of length N bits to N/2 bits, cutting the possibilities in half and making 256 bit reduced to a mere 128, the absolute baseline of security by current standards... Let alone future standards as computational power become …
Hybrid asymmetric encryption scheme
Hi, looking to get some eyeballs on the following scheme / idea Imagine you have a ML-KEM keypair, and a Classic McEliece keypair. You generate a shared secret with each KEM, then the result, you XOR it together to derive a final key This final key will be used as …