RELEASE NOTES: JDK 13.0.9

Improve Encoding of TLS Application-Layer Protocol Negotiation (ALPN) Values

Certain TLS ALPN values couldn't be properly read or written by the SunJSSE provider. This is due to the choice of Strings as the API interface and the undocumented internal use of the UTF-8 Character Set which converts characters larger than U+00007F (7-bit ASCII) into multi-byte arrays that may not be expected by a peer.

ALPN values are now represented using the network byte representation expected by the peer, which should require no modification for standard 7-bit ASCII-based character Strings. However, SunJSSE now encodes/decodes String characters as 8-bit ISO88591/LATIN-1 characters. This means applications that used characters above U+000007F that were previously encoded using UTF-8 may need to either be modified to perform the UTF-8 conversion, or set the Java security property jdk.tls.alpnCharset to "UTF-8" revert the behavior.

Improve Encoding of TLS Application-Layer Protocol Negotiation (ALPN) Values

Certain TLS ALPN values couldn't be properly read or written by the SunJSSE provider. This is due to the choice of Strings as the API interface and the undocumented internal use of the UTF-8 character set which converts characters larger than U+00007F (7-bit ASCII) into multi-byte arrays that may not be expected by a peer.

SunJSSE now encodes/decodes String characters as 8-bit ISO88591/LATIN-1 characters. This means applications that used characters above U+000007F that were previously encoded using UTF-8 may need to either be modified to perform the UTF-8 conversion, or set the Java security property jdk.tls.alpnCharset to "UTF-8" revert the behavior.

See the updated guide at https://docs.oracle.com/javase/8/docs/technotes/guides/security/jsse/alpn.html for more information.

Support for certificate_authorities Extension

The "certificate_authorities" extension is an optional extension introduced in TLS 1.3. It is used to indicate the certificate authorities (CAs) that an endpoint supports and should be used by the receiving endpoint to guide certificate selection.

With this JDK release, the "certificate_authorities" extension is supported for TLS 1.3 in both the client and the server sides. This extension is always present for client certificate selection, while it is optional for server certificate selection.

Applications can enable this extension for server certificate selection by setting the jdk.tls.client.enableCAExtension system property to true. The default value of the property is false.

Note that if the client trusts more CAs than the size limit of the extension (less than 2^16 bytes), the extension is not enabled. Also, some server implementations do not allow handshake messages to exceed 2^14 bytes. Consequently, there may be interoperability issues when jdk.tls.client.enableCAExtension is set to true and the client trusts more CAs than the server implementation limit.

Tools Warn If Weak Algorithms Are Used

The keytool and jarsigner tools have been updated to warn users when weak cryptographic algorithms are used in keys, certificates, and signed JARs before they are disabled. The weak algorithms are set in the jdk.security.legacyAlgorithms security property in the java.security configuration file. In this release, the tools issue warnings for the SHA-1 hash algorithm and 1024-bit RSA/DSA keys.