Stefan Kölbl
Stefan Kölbl
Latest posts
From Inventory to Agility: A CISO's Guide to Robust Key Management
Cryptographic Agility and Key Rotation
Why Hybrid Deployments Are Key to Secure PQC Migration
A note on SPHINCS+ parameter sets
Google's Threat model for Post-Quantum Cryptography
Example Talk: Recent Work
Example Talk Dr. Alex Johnson · Meta AI Research Overview Multimodal LLMs Efficient training Responsible AI Code & Math def score ( x : int ) -> int : return x * x $$ E = mc^2 $$ Dual Column Layout Left Column Point A Point B Point C Right Column Detail 1 Detail 2 Detail 3 Main Content (2/3 width) This column takes up twice the space of the right column. def example (): return 'code works too'…
Experience
Post-quantum Cryptography at Google
Crypto Agility and Post-Quantum Cryptography @ Google
Why Google now uses post-quantum cryptography for internal comms
How to Abuse and Fix Authenticated Encryption Without Key Commitment
How to Abuse and Fix Authenticated Encryption Without Key Commitment
SPHINCS+ / SLH-DSA
SPHINCS+ is a stateless hash-based signature scheme standardized as . It is an advancement of the SPHINCS signature scheme, incorporating several improvements designed to reduce signature size.
Skinny
Skinny is a family of lightweight tweakable block ciphers designed to be competitive with the most efficient lightweight block ciphers while providing a higher level of security and flexibility through its tweakable structure. It has been standardized in ISO/IEC 18033-7.
CryptoSMT
CryptoSMT is a tool for automating differential cryptanalysis for cryptographic primitives. It uses SMT solvers to find optimal differential trails and calculate probabilities for various block ciphers and hash functions.
Gimli
Gimli is a cryptographic permutation designed for high performance and security across a wide range of platforms. It is part of the and is integrated into for efficient cryptographic operations.
Haraka
Haraka is a high-performance hash function family specifically designed for short inputs. It leverages the AES-NI instruction set found in modern CPUs to achieve extremely high throughput, making it ideal for hash-based signature schemes like SPHINCS+.
Pyjamask
Pyjamask is a block cipher submitted to the NIST Lightweight Cryptography project. It was designed with a focus on efficient implementation in software, particularly on platforms with limited resources. A key feature of Pyjamask is its suitability for higher-order masking, providing strong resistance against side-channel attacks.