Kirill Abrams

Kirill Abrams's personal blog

Founder & CEO, UmbrellaX TOO

This is where I write about end-to-end encryption, post-quantum cryptography, jurisdictional risk, and the design decisions behind UmbrellaX. Personal opinions, not press releases.

More about me .com

Encryption and protocol briefings

I explain the cryptographic choices behind UmbrellaX, including MLS, Signal Protocol trade offs, post-quantum hardening, group key management, and what encryption does not hide.
What I cover
  • end to end encryption explained
  • MLS messaging protocol
  • Signal Protocol vs MLS
  • encrypted group chat protocol
Hands holding a phone with an RCS warning that resending as SMS removes end-to-end encryption.
Encryption

Is RCS encrypted? How to check your chat

RCS can be end-to-end encrypted, but support varies. Check the lock on iPhone and Android, understand missing encryption, and avoid an unsafe SMS fallback.

Oct 1 guide 5 min New
Two people compare a Signal safety number on their phones in person.
Encryption

Signal safety number: how to verify it safely

Learn what a Signal safety number verifies, how to compare it safely, what a match cannot prove, and when automatic verification still needs a manual check.

Sep 8 guide 5 min New
A person makes a private voice call beside an illustration of its network route.
Encryption

Encrypted calling app: what I would trust

How I evaluate an encrypted calling app: media encryption, IP exposure, relay tradeoffs, verification, call logs, and UmbrellaX design choices.

Aug 6 guide 5 min New
A person pauses at a changed-encryption-key notification before sending a message.
Encryption

Key change notifications in encrypted messaging

A founder's guide to key change notifications, safety numbers, device trust, verification UX, and why UmbrellaX treats alerts as security.

Jul 30 guide 5 min New
Two people review a removed group member and a new group key on a tablet.
Encryption

Secure group messaging: what to check

A founder's practical test for secure group messaging: encryption defaults, group key changes, metadata, recovery, and why UmbrellaX uses MLS.

May 31 guide 5 min New
Two engineers compare Signal sender keys with an MLS TreeKEM group diagram.
Encryption

Signal Protocol vs MLS: the bytes on the wire, the trade offs that matter

Signal Protocol and MLS (RFC 9420) both deliver end to end encryption. They diverge on groups, post quantum, and adoption surface. A builder's comparison from someone who picked MLS.

May 10 analysis 5 min New
Two people message from separate homes, with a diagram showing that only endpoints read the content.
Encryption

End to end encryption explained: what it is, what it is not, and how UmbrellaX implements it

A byte level explainer of end to end encryption. What E2EE protects, what it does not, which protocols matter in 2026, and how UmbrellaX uses MLS plus post quantum hardening.

Apr 29 pillar 5 min New