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FundamentalsAdvanced

TLS Cipher Suite Decoder

Decode cipher suite strings like TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384. Understand key exchange, encryption, and MAC.

Interactive Demo

Cipher Suite Disgronifier

Break down intimidating cipher suite strings into understandable pieces

Step 0 of 6

The Disgronifier - break down cipher suites

The Disgronifier

Select a cipher suite to analyze:

TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384

Security Rating: SECUREA

Forward Secrecy-ECDHE provides ephemeral keys

Strong Encryption-AES-256 is industry standard

AEAD Mode-GCM provides authenticated encryption

Strong Hash-SHA384 is collision-resistant

RSA Auth-Consider ECDSA for better performance

Recommended for: Production servers, general use

Component Deep Dives

Algorithm	Security	Notes
ECDHE Elliptic Curve Diffie-Hellman Ephemeral	strong	Best choice. New key each session.
DHE Diffie-Hellman Ephemeral	depends	Good if 2048+ bit. Slower than ECDHE.
ECDH Elliptic Curve Diffie-Hellman	ok	Static key - compromise reveals past traffic
RSA RSA Key Transport	weak	Server key used directly. AVOID.
PSK Pre-Shared Key	depends	For IoT, constrained devices

Forward Secrecy Explained:

WITHOUT (RSA key exchange):

Server private key stolen → ALL past traffic decryptable

WITH (ECDHE):

Private key stolen → Only current session at risk. Past sessions still safe!

TLS 1.3 Simplified Format

TLS 1.2 Format (verbose):

TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384

7 components to understand

TLS 1.3 Format (simplified):

TLS_AES_256_GCM_SHA384

Just cipher + hash! Key exchange is always ephemeral.

TLS 1.3 Only Allows:

TLS_AES_256_GCM_SHA384

AES-256, strongest

TLS_AES_128_GCM_SHA256

AES-128, faster

TLS_CHACHA20_POLY1305_SHA256

Great for mobile

TLS_AES_128_CCM_SHA256

IoT/constrained

Key Insight:TLS 1.3 removed all the bad options. You can't accidentally pick a weak cipher - they simply don't exist in TLS 1.3.

Recommended Server Configuration

Nginx (Modern)

ssl_protocols TLSv1.2 TLSv1.3;
ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384;
ssl_prefer_server_ciphers off;

Apache

SSLProtocol all -SSLv3 -TLSv1 -TLSv1.1
SSLCipherSuite ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384
SSLHonorCipherOrder off

Check Your Cipher Suites

# Test what cipher suites a server supports
nmap --script ssl-enum-ciphers -p 443 example.com

# OpenSSL test specific cipher
openssl s_client -connect example.com:443 -cipher 'ECDHE-RSA-AES256-GCM-SHA384'

ASecure

BGood

CLegacy

DWeak

FBroken

Want to learn more?

Read our complete guide on understanding cipher suites

See Glossary Read the Guide

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