Another Challenge of Hash Functions

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TLS Server Name Indication Extension and Unrecognized_name

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Heavy Pond, Jianfengling National Forest Park, Ledong, Hainan, China It's getting hot that some TLS/HTTPS server failed with "unrecognized_name". For example, the Adobe AIR 3 Code Signing Certificate Problem , the ADT handshake alert , and the jarsigner issue with timestamp.geotrust.com , etc. This entry will discussion some background of the "unrecognized_name" alert, and the TLS Server Name Indication (SNI) extension. Background "Unrecognized_name" is an error alert, define by RFC4366 .  In section 4 of RFC4366 : - "unrecognized_name": this alert is sent by servers that receive a server_name extension request, but do not recognize the server name. This message MAY be fatal. And in section 3.1 of of RFC4366 : If the server understood the client hello extension but does not recognize the server name, it SHOULD send an "unrecognized_name" alert (which MAY be fatal). From above sections, we see that "unrecognized...
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Java™ SE 7 Release Security Enhancements - Weak Cryptography Control

Weak cryptographic algorithms can now be disabled in Java SE 7 release. The MD2 Message-Digest Algorithm was disabled by default in Sun PKIX provider and SunJSSE provider. The MD2 algorithm is a cryptographic hash function developed by Ronald Rivest in 1989 , and was published in 1992 as an Informational RFC (RFC 1319) .; RFC 6149 moves RFC 1319/MD2 to historic status, "Since its publication, MD2 has been shown to not be collision-free, albeit successful collision attacks for properly implemented MD2 are not that damaging. Successful pre-image and second pre-image attacks against MD2 have been shown." Although MD2 is no longer considered secure, it remains in use in public key infrastructures as part of certificates generated with MD2 and RSA. An a countermeasure of the vulnerability, Java SE has disabled MD2 algorithm in certification path building and validation. You may wonder, Java SE has disabled MD2 algorithm in certification path building and validation in ...
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JEP 115: AES-GCM CipherSuites in JDK 8

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Chengdu, China RFC 5288 describes the use of AES in Galois Counter Mode ( GCM ) (AES-GCM) with various key exchange mechanisms as a cipher suite for TLS. AES-GCM is an authenticated encryption with associated data (AEAD) cipher (as defined in TLS 1.2 ) providing both confidentiality and data origin authentication. Java SE had already defined the AES-GCM interfaces in Java SE 7 .  In the coming Java SE 8, as an implementation of JEP 115 , AES-GCM algorithms is implemented in SunJCE provider, and AES-GCM cipher suites are implemented in SunJSSE provider. The following SSL/TLS AEAD/GCM cipher suites, in preference order, are enabled by default in SunJSSE provider for TLS version 1.2: TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 (RFC 5289) TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 (RFC 5289) TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (RFC 5289) TLS_RSA_WITH_AES_256_GCM_SHA384 (RFC 5288) TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384 (RFC 5289) TLS_ECDH_RSA_WITH_AES_...
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