The constant speedup theorem, so well known from Tur-ing machine based complexity theory, is shown false for a natural imperative programming language I that manipulates tree-structured data. This relieves a tension between general programming practice, where linear factors are essential, and complexity theory, where linear time changes are traditionally regarded as trivial. Speciically, there ...

Side-channel attacks are a serious threat to securitycritical software. To mitigate remote timing and cachetiming attacks, many ubiquitous cryptography software libraries feature constant-time implementations of cryptographic primitives. In this work, we disclose a vulnerability in OpenSSL 1.0.1u that recovers ECDSA private keys for the standardized elliptic curve P-256 despite the library feat...