TLS Versions and Cipher Suites

Transport Layer Security (TLS) protocol versions and cipher suites determine the cryptographic algorithms used to secure Cassandra communications. Selecting appropriate versions and ciphers is critical for both security and interoperability.

TLS Protocol Versions

Version Comparison

Version	Status	Java Requirement	Cassandra Support
SSL 3.0	Deprecated	-	Disabled by default
TLS 1.0	Deprecated	Java 6+	Supported, not recommended
TLS 1.1	Deprecated	Java 7+	Supported, not recommended
TLS 1.2	Current	Java 7+	Recommended minimum
TLS 1.3	Current	Java 11+	Recommended (Cassandra 4.0+)

Protocol Security Status

TLS 1.3 (Recommended)

Removed obsolete cryptographic algorithms
Faster handshake (1-RTT, 0-RTT resumption)
Forward secrecy mandatory
Simplified cipher suite configuration

TLS 1.2 (Acceptable)

Widely supported
Secure when configured with strong cipher suites
Requires careful cipher suite selection

TLS 1.0/1.1 (Deprecated)

Vulnerable to BEAST, POODLE attacks
PCI-DSS compliance prohibits use
Disable in production environments

Cipher Suites

A cipher suite defines the combination of algorithms used for:

Key exchange (how keys are established)
Authentication (how identity is verified)
Encryption (how data is protected)
Message authentication (how integrity is verified)

TLS 1.3 Cipher Suites

TLS 1.3 simplified cipher suite naming. All TLS 1.3 suites use AEAD encryption and are considered secure.

Cipher Suite	Encryption	Notes
`TLS_AES_256_GCM_SHA384`	AES-256-GCM	Recommended
`TLS_AES_128_GCM_SHA256`	AES-128-GCM	Good performance
`TLS_CHACHA20_POLY1305_SHA256`	ChaCha20-Poly1305	Good for non-AES-NI CPUs

TLS 1.2 Cipher Suites

TLS 1.2 cipher suites require careful selection. Use only AEAD ciphers with forward secrecy.

Recommended:

Cipher Suite	Key Exchange	Encryption
`TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384`	ECDHE	AES-256-GCM
`TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256`	ECDHE	AES-128-GCM
`TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384`	ECDHE	AES-256-GCM
`TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256`	ECDHE	AES-128-GCM
`TLS_DHE_RSA_WITH_AES_256_GCM_SHA384`	DHE	AES-256-GCM
`TLS_DHE_RSA_WITH_AES_128_GCM_SHA256`	DHE	AES-128-GCM

Avoid:

Pattern	Reason
`_CBC_`	Vulnerable to padding oracle attacks
`_RC4_`	RC4 is broken
`_DES_`	DES is weak
`_NULL_`	No encryption
`_EXPORT_`	Weak export-grade cryptography
`TLS_RSA_*`	No forward secrecy

Forward Secrecy

Forward secrecy (also called perfect forward secrecy) ensures that session keys cannot be compromised even if the server’s private key is later exposed.

How It Works

Without forward secrecy (RSA key exchange):

Session keys are encrypted with the server’s RSA public key
If the private key is compromised, all past sessions can be decrypted

With forward secrecy (ECDHE/DHE key exchange):

Session keys are generated using ephemeral Diffie-Hellman
Each session uses unique keys
Compromised private key cannot decrypt past sessions

Configuration

Enable forward secrecy by prioritizing ECDHE and DHE cipher suites:

server_encryption_options:
    cipher_suites:
        - TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
        - TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256

Configuration Examples

Cassandra 4.0+ with TLS 1.3

server_encryption_options:
    internode_encryption: all
    protocol: TLS
    accepted_protocols:
        - TLSv1.3
        - TLSv1.2
    cipher_suites:
        - TLS_AES_256_GCM_SHA384
        - TLS_AES_128_GCM_SHA256
        - TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
        - TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256

TLS 1.2 Only (Java 8)

server_encryption_options:
    internode_encryption: all
    protocol: TLS
    accepted_protocols:
        - TLSv1.2
    cipher_suites:
        - TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
        - TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
        - TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
        - TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256

Explicitly Disable Weak Protocols

server_encryption_options:
    # Only allow TLS 1.2+
    accepted_protocols:
        - TLSv1.2
        - TLSv1.3
    # Explicitly exclude weak protocols (redundant but explicit)
    # SSLv3, TLSv1, TLSv1.1 are not listed

Verifying TLS Configuration

Check Supported Protocols

# Test TLS 1.3
openssl s_client -connect cassandra-node:9042 -tls1_3

# Test TLS 1.2
openssl s_client -connect cassandra-node:9042 -tls1_2

# Test TLS 1.1 (should fail if properly configured)
openssl s_client -connect cassandra-node:9042 -tls1_1

Check Cipher Suites

# Show negotiated cipher suite
openssl s_client -connect cassandra-node:9042 -tls1_2 2>/dev/null | grep "Cipher is"

# Test specific cipher suite
openssl s_client -connect cassandra-node:9042 -cipher ECDHE-RSA-AES256-GCM-SHA384

Using nmap for TLS Analysis

# Scan TLS configuration
nmap --script ssl-enum-ciphers -p 9042 cassandra-node

Java Version Considerations

Java 8

TLS 1.2 supported
TLS 1.3 not available
Some GCM cipher suites may have performance issues

Java 11+

TLS 1.3 supported
Improved TLS performance
Recommended for production deployments

JVM Options

# Disable weak protocols at JVM level
-Djdk.tls.disabledAlgorithms=SSLv3,TLSv1,TLSv1.1,RC4,DES,MD5withRSA,DH keySize < 1024,EC keySize < 224

# Enable TLS 1.3 (Java 11+)
-Djdk.tls.client.protocols=TLSv1.3,TLSv1.2

Compliance Requirements

Standard	Minimum TLS Version	Notes
PCI-DSS 3.2+	TLS 1.2	TLS 1.0/1.1 prohibited since 2018
HIPAA	TLS 1.2	Strong encryption required
NIST SP 800-52	TLS 1.2	TLS 1.3 recommended
FedRAMP	TLS 1.2	Federal systems requirement

Encryption Overview - Why encryption is essential
PKI Fundamentals - Certificate concepts
Cassandra Configuration - Detailed configuration options