Conscrypt's Capabilities

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.

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.

AlgorithmParameters

• AES
• ChaCha20
• DESEDE
• EC
• GCM
• OAEP
• PSS

Conscrypt's EC AlgorithmParameters implementation only supports named curves.

CertificateFactory

• X509

KeyAgreement

• ECDH

KeyFactory

• EC
• RSA

KeyGenerator

• AES
• ARC4
• ChaCha20
• DESEDE
• HmacMD5
• HmacSHA1
• HmacSHA224
• HmacSHA256
• HmacSHA384
• HmacSHA512

KeyPairGenerator

• EC
• RSA

Mac

• HmacMD5
• HmacSHA1
• HmacSHA224
• HmacSHA256
• HmacSHA384
• HmacSHA512

MessageDigest

• MD5
• SHA-1
• SHA-224
• SHA-256
• SHA-384
• SHA-512

SecretKeyFactory

• DESEDE

SecureRandom

• SHA1PRNG

Signature

• MD5withRSA
• NONEwithECDSA
• NONEwithRSA
• SHA1withRSA
• SHA1withECDSA
• SHA1withRSA/PSS
• SHA224withRSA
• SHA224withECDSA
• SHA224withRSA/PSS
• SHA256withRSA
• SHA256withECDSA
• SHA256withRSA/PSS
• SHA384withRSA
• SHA384withECDSA
• SHA384withRSA/PSS
• SHA512withRSA
• SHA512withECDSA
• SHA512withRSA/PSS

Elliptic Curves

Conscrypt supports the following curves in EC crypto operations (such as ECDSA signatures) and TLS:

Curve	EC Crypto	TLS
secp224r1	X
prime256v1 (aka secp256r1)	X	X
secp384r1	X	X
secp521r1	X
x25519		X