Client Portal
Access your security dashboard and reports
Security protocols fail not from broken primitives but from composition errors—subtle flaws in how cryptographic operations combine under adversarial conditions. Formal verification transforms protocol security from belief to mathematical proof.
The history of cryptographic protocols is a history of broken assumptions. WEP, SSL 3.0, TLS 1.0, and countless custom protocols have failed not because AES or RSA were compromised, but because protocol logic contained exploitable flaws. POODLE, BEAST, CRIME, Heartbleed, and ROBOT attacks exploited protocol-level vulnerabilities invisible to code review.
Formal verification proves security properties mathematically—covering all possible attack scenarios, not just those anticipated by developers.
Cryptographic protocol analysis emerged from the foundational work of Dolev and Yao (1983), who formalized the symbolic model of protocol execution wherein the adversary controls the network absolutely—intercepting, replaying, and constructing messages from observed components. This "network attacker" model remains the foundation of modern protocol verification.
The transition from symbolic to computational security models represents one of cryptography's great theoretical achievements. While symbolic analysis treats cryptographic primitives as perfect black boxes, computational analysis models them as probabilistic algorithms secure against polynomial-time adversaries. Tools like CryptoVerif bridge this gap, providing machine-checked proofs in the computational model.
Our protocol verification practice synthesizes both approaches: symbolic analysis for rapid exploration of protocol logic, computational verification for deployment-grade assurance, and implementation testing to verify code matches specification.
Each verification tool embodies different security models and analysis techniques. Tool selection depends on protocol complexity, required assurance level, and threat model.
| Tool | Security Model | Automation | Best For |
|---|---|---|---|
| ProVerif | Symbolic (Dolev-Yao) | Fully automatic | Initial protocol exploration, authentication properties |
| Tamarin Prover | Symbolic with state | Semi-automatic | Stateful protocols, complex key management |
| CryptoVerif | Computational | Semi-automatic | Concrete security bounds, deployment assurance |
| EasyCrypt | Computational | Interactive | Complex reductions, research-grade proofs |
| Coq/F* | General purpose | Interactive | Implementation verification, verified code |
TLS 1.3 (RFC 8446) represents the culmination of decades of protocol evolution, incorporating lessons from attacks on prior versions. The protocol was formally verified during standardization using ProVerif, Tamarin, and CryptoVerif—a first for IETF protocols. However, implementation configuration remains critical: cipher suite selection, certificate validation, and session resumption all present security-relevant choices.
# Cipher Suites (TLS 1.3) TLS_AES_256_GCM_SHA384 TLS_CHACHA20_POLY1305_SHA256 TLS_AES_128_GCM_SHA256 # Key Exchange Groups (RFC 8446 §4.2.7) x25519 # Curve25519 ECDHE secp256r1 # NIST P-256 (fallback) x448 # Curve448 (high security) # Signature Algorithms ecdsa_secp256r1_sha256 # Primary rsa_pss_rsae_sha256 # RSA-PSS (required for RSA certs) ed25519 # EdDSA (if supported) # Session Resumption session_tickets: enabled # 0-RTT disabled by default ticket_lifetime: 3600 # 1 hour maximum anti_replay: required # Mandatory for 0-RTT
Configuration derived from Mozilla SSL Configuration Generator (Modern) with additional hardening per NIST SP 800-52 Rev. 2 guidelines.
The ROBOT (Return Of Bleichenbacher's Oracle Threat) attack, disclosed in December 2017, demonstrated that RSA encryption in TLS remained vulnerable to a 19-year-old attack variant. Despite Bleichenbacher's 1998 publication describing adaptive chosen-ciphertext attacks against PKCS#1 v1.5, major vendors including F5, Cisco, Citrix, and Palo Alto shipped vulnerable implementations in 2017.
The attack exploits timing or error message differences when TLS servers process RSA-encrypted premaster secrets. A server reveals whether decrypted plaintext has correct PKCS#1 v1.5 padding through observable side channels.
Lesson: Implementation-level vulnerabilities persist despite protocol-level fixes. Formal verification of protocol logic must be complemented by implementation testing and side-channel analysis.
Our protocol verification practice builds on decades of academic research in formal methods and cryptographic security.
Our cryptographic engineers will analyze your protocol design and implementation, providing formal verification results and remediation guidance.
Tell us about your security requirements. We respond within 24 hours.
Access your security dashboard and reports