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Cryptographic Analysis · hypnguyen1209 | DecimalAI

securityby hypnguyen1209

Cryptographic Analysis

hypnguyen1209/crypto-analysis

Source hypnguyen1209/offensive-claude ↗License MIT

Use when assessing cryptography — TLS/PKI auditing, RSA/ECC key attacks, ECDSA nonce lattice recovery, symmetric/AEAD misuse, JWT/JOSE forgery, hash cracking, post-quantum migration review

SkillScore95Maintained

Automatic

Security & AppSec pack

Last verified 8/21/2026

What it changes

Passed 21 of 22 test cases with the skill, and 18 of 22 without it.

Without skill82%

With skill95%

Checks it passed that the model alone missed

includes the --full flag
includes the --robot flag
identifies CVE-2024-54150

and 1 more in the full report

3 fixed18 passed either way1 still failing0 broke

Pass-rate lift: +14 pp
Tokens: +148%
Agent turns: 0%
Response time: -5%

Model gemini-3.6-flashMeasured 8/21/2026v121 of 22 cases passed with skill

Tokens, turns and time describe resource use, not a dollar price.

Use this skill

Save it into your project's skills folder. Claude Code picks it up in its next session.

curl -fsSL --create-dirs -o .claude/skills/hypnguyen1209-crypto-analysis/SKILL.md https://app.decimal.ai/s/hypnguyen1209-crypto-analysis/SKILL.md

Want it pinned and updatable? pip install "decimalai>=0.15", then decimalai skills add hypnguyen1209-crypto-analysis, and start Claude Code with claude --plugin-dir "$(git rev-parse --show-toplevel)/.agents"

1 · One-time — install the CLI (docs ↗)

pip install "decimalai>=0.15"

2 · Get the skill — writes .agents/skills/hypnguyen1209-crypto-analysis/ and pins it in .decimal/skills.lock

decimalai skills add hypnguyen1209-crypto-analysis

No CLI? Get the same file — curl · raw file

curl -fsSL --create-dirs -o .claude/skills/hypnguyen1209-crypto-analysis/SKILL.md https://app.decimal.ai/s/hypnguyen1209-crypto-analysis/SKILL.md

Raw file: /s/hypnguyen1209-crypto-analysis/SKILL.md ↗ · machine-readable summary at /s/hypnguyen1209-crypto-analysis.json ↗

Safety checks: 3 of 3 passed

Code scan CleanIntent PassedContent Clean

See it in action

One of 3 test cases the skill fixed. Same model, same prompt, with and without the skill.

1 of 3

Prompt

Approximately how many HTTP decrypt attempts per byte are required on average during a standard CBC padding oracle attack?

What was checked, without and with the skill
Checked	Without skill	With skill
mentions 256 attempts per byte	Missed	Passed

case-14 · gemini-3.6-flash · 8/21/2026 · answers are capped and redacted

What's inside

The instructions your model reads when the skill loads.

SKILL.md85 lines14 filesincludes scripts

Cryptographic Analysis

When to Activate

Auditing TLS/SSL/SSH configurations and X.509 PKI (cipher suites, downgrade, protocol flaws)
Reviewing crypto implementations in source code or captured traffic
Attacking weak RSA/ECC keys (CTF and real-world weak-key hygiene)
Recovering ECDSA/DSA private keys from reused or biased nonces (lattice/HNP)
Exploiting symmetric/AEAD misuse: padding oracles, GCM nonce reuse, key-commitment
Forging JWT/JOSE tokens (algorithm confusion, none, jwk/jku/kid injection)
Cracking password hashes and grading KDF strength
Assessing post-quantum readiness ("harvest now, decrypt later" exposure)

Technique Map

Technique	ATT&CK	CWE	Reference	Script
TLS cipher/protocol downgrade audit	T1600.001	CWE-326	references/tls-pki-audit.md	scripts/tls_audit.py
Terrapin SSH prefix truncation (CVE-2023-48795)	T1557	CWE-222	references/tls-pki-audit.md	scripts/tls_audit.py
Marvin/Bleichenbacher RSA timing oracle	T1600	CWE-208	references/tls-pki-audit.md	scripts/tls_audit.py
X.509 / CT-log shadow-asset discovery	T1589	CWE-295	references/tls-pki-audit.md	scripts/tls_audit.py
RSA weak-key factoring (Fermat/Wiener/common-modulus)	T1600	CWE-326	references/rsa-attacks.md	scripts/rsa_attack.py
Coppersmith partial-key & ROCA (CVE-2017-15361)	T1600	CWE-310	references/rsa-attacks.md	scripts/rsa_attack.py
Hastad broadcast / batch-GCD	T1600	CWE-326	references/rsa-attacks.md	scripts/rsa_attack.py
ECDSA nonce reuse key recovery	T1552.004	CWE-323	references/ecc-nonce-attacks.md	scripts/ecdsa_lattice.py
Biased-nonce lattice/HNP (Minerva, PuTTY CVE-2024-31497)	T1552.004	CWE-1241	references/ecc-nonce-attacks.md	scripts/ecdsa_lattice.py
Psychic signature (0,0) (CVE-2022-21449)	T1606.001	CWE-347	references/ecc-nonce-attacks.md	scripts/ecdsa_lattice.py
CBC padding oracle (byte-by-byte decrypt)	T1040	CWE-209	references/symmetric-aead.md	scripts/padding_oracle.py
AES-GCM nonce reuse "forbidden attack"	T1040	CWE-323	references/symmetric-aead.md	scripts/gcm_nonce_reuse.py
AEAD key-commitment / invisible salamanders / partitioning oracle	T1606	CWE-347	references/symmetric-aead.md	scripts/gcm_nonce_reuse.py
JWT algorithm confusion RS256→HS256 (CVE-2024-54150)	T1606.001	CWE-347	references/jwt-jose.md	scripts/jwt_forge.py
JWT alg=none / jwk / jku / kid injection	T1606.001	CWE-347	references/jwt-jose.md	scripts/jwt_forge.py
Hash identification & GPU cracking	T1110.002	CWE-916	references/hash-pq.md	scripts/hash_triage.py
Weak KDF / fast-hash password storage	T1110.002	CWE-916	references/hash-pq.md	scripts/hash_triage.py
Post-quantum / HNDL exposure review	T1600	CWE-327	references/hash-pq.md	scripts/tls_audit.py

Quick Start

# 0. TLS/PKI posture in one shot (downgrade, ROBOT, SWEET32, Terrapin, cert/CT)

Track record

Benchmark

21 / 22

test cases passed, vs 18 / 22 without

Adoption

Users: 0
Times used: 0

Safety and source details

SkillSafety

✓ 3 of 3 passed

Code scan15 of 15 checks clean

0 critical · 0 warning · 0 info — scanner v4 — 8/3/2026

View 15 scanner checks

live_secretremote_code_executionreverse_shelldata_exfiltrationssrf_metadataagent_snoopinganti_refusaldestructive_commandsobfuscated_unicodeunicode_homoglyphopaque_blobsuspicious_urltool_overreachtrigger_abuseprompt_injection_phrasing

IntentSafe

LLM judge · does the skill do what it claims

ContentClean

LLM judge · policy & harmful-content review

Source

Imported

hypnguyen1209 / offensive-claude

skills/crypto-analysis/SKILL.md

View on GitHub ↗

License MITImported 8/3/2026Version v1Bundled 13 files · scripts

Other skills for the same job

Published skills whose descriptions closely match this one, with their headline benchmark lift.

transilienceai/cryptographyCryptanalysis techniques — lattice attacks, padding oracles, weak-RNG exploitation, signature forgery, secret-sharing recovery.Close match+27 pp pass-rate lift

More skills from the same source and nearby in the registry, with their headline benchmark lift.

Ready to supercharge your AI agents?

See it in action

What's inside

Cryptographic Analysis

When to Activate

Technique Map

Quick Start

Track record

Benchmark

Adoption

SkillSafety

Source

Other skills for the same job

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