Conscrypt's Capabilities

May 27, 2026 · View on GitHub

Conscrypt is relatively selective in choosing the set of primitives to provide, focusing on the most important and widely-used algorithms. Following is a list of JCA algorithm names and other identifiers that are supported by Conscrypt.

TLS

Protocol Versions

SSLv3 (ignored)
TLSv1
TLSv1.1
TLSv1.2
TLSv1.3

Conscrypt supports TLS v1.0-1.3. For backwards compatibility it will accept SSLv3 in calls to methods like setEnabledProtocols() but will ignore it.

SSLContext

Default
SSL
TLS
TLSv1
TLSv1.1
TLSv1.2
TLSv1.3

Conscrypt provides the above set of SSLContext algorithm names for JSSE purposes, including the special value Default, which is used to determine the value of SSLContext.getDefault(). The Default, SSL, TLS, and TLSv1.3 values return a context where TLS v1.0-1.3 are all enabled; the others return a context with TLS v1.0-1.2 enabled.

Cipher Suites

Enabled

TLS 1.0-1.2
- TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
- TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
- TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
- TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
- TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
- TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
- TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
- TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
- TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
- TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
- TLS_RSA_WITH_AES_128_CBC_SHA
- TLS_RSA_WITH_AES_128_GCM_SHA256
- TLS_RSA_WITH_AES_256_CBC_SHA
- TLS_RSA_WITH_AES_256_GCM_SHA384
TLS 1.3
- TLS_AES_128_GCM_SHA256
- TLS_AES_256_GCM_SHA384
- TLS_CHACHA20_POLY1305_SHA256

The above cipher suites are enabled by default when the associated version of the protocol is enabled. The TLS 1.3 cipher suites cannot be customized; they are always enabled when TLS 1.3 is enabled, and any attempt to disable them via a call to setEnabledCipherSuites() is ignored.

Supported But Not Enabled

TLS 1.0-1.2
- SSL_RSA_WITH_3DES_EDE_CBC_SHA
- TLS_ECDHE_PSK_WITH_AES_128_CBC_SHA
- TLS_ECDHE_PSK_WITH_AES_256_CBC_SHA
- TLS_ECDHE_PSK_WITH_CHACHA20_POLY1305_SHA256
- TLS_PSK_WITH_AES_128_CBC_SHA
- TLS_PSK_WITH_AES_256_CBC_SHA

The above cipher suites are supported, but not enabled by default. TLS 1.3 cipher suites cannot be customized, so there are no cipher suites that are supported but not enabled.

Supported Named Groups

These can be set with SSLParameters::setNamedGroups or by setting the system property jdk.tls.namedGroups.

X25519
P-256 (secp256r1)
P-384 (secp384r1)
P-521 (secp521r1)
X25519MLKEM768
X25519Kyber768Draft00
MLKEM1024

X25519, P-256 and P-384 are enabled by default.

Cryptography

Cipher

AES/CBC/NoPadding
AES/CBC/PKCS5Padding
AES/CTR/NoPadding
AES/ECB/NoPadding
AES/ECB/PKCS5Padding
AES/GCM-SIV/NoPadding

AES with 128, 192, or 256-bit keys.

AES/GCM/NoPadding

AES/GCM with 128 or 256-bit keys.

AES_128/CBC/NoPadding
AES_128/CBC/PKCS5Padding
AES_128/ECB/NoPadding
AES_128/ECB/PKCS5Padding
AES_128/GCM/NoPadding
AES_128/GCM-SIV/NoPadding
AES_256/CBC/NoPadding
AES_256/CBC/PKCS5Padding
AES_256/ECB/NoPadding
AES_256/ECB/PKCS5Padding
AES_256/GCM/NoPadding
AES_256/GCM-SIV/NoPadding

Key-restricted versions of the AES ciphers.

ARC4

The RC4 stream cipher.

ChaCha20/NONE/NoPadding
ChaCha20/Poly1305/NoPadding

ChaCha with 20 rounds, 96-bit nonce, and 32-bit counter as described in RFC 7539, either with or without a Poly1305 AEAD authenticator.

DESEDE/CBC/NoPadding
DESEDE/CBC/PKCS5Padding

Triple DES with either two or three intermediate keys.

RSA/ECB/NoPadding
RSA/ECB/OAEPPadding
RSA/ECB/OAEPWithSHA-1AndMGF1Padding
RSA/ECB/OAEPWithSHA-224AndMGF1Padding
RSA/ECB/OAEPWithSHA-256AndMGF1Padding
RSA/ECB/OAEPWithSHA-384AndMGF1Padding
RSA/ECB/OAEPWithSHA-512AndMGF1Padding
RSA/ECB/PKCS1Padding

Conscrypt's OAEP ciphers (eg, RSA/ECB/OAEPWithSHA-256AndMGF1Padding) use the named digest for both the main digest and the MGF1 digest. This differs from the behavior of some other providers, including the ones bundled with OpenJDK, which always use SHA-1 for the MGF1 digest. For maximum compatibility, you should use RSA/ECB/OAEPPadding and initialize it with an OAEPParameterSpec.