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https://issues.apache.org/jira/browse/TRAFODION-2080?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15632327#comment-15632327
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liu ming commented on TRAFODION-2080:
-------------------------------------
md5
sha
sha1
sha256
will be implemented as TRAFODION-2229
> Add builtin functions for certain OpenSSL digest functions
> ----------------------------------------------------------
>
> Key: TRAFODION-2080
> URL: https://issues.apache.org/jira/browse/TRAFODION-2080
> Project: Apache Trafodion
> Issue Type: Improvement
> Components: sql-general
> Affects Versions: 2.1-incubating
> Reporter: Suresh Subbiah
> Assignee: Suresh Subbiah
>
> Trafodion should support the following functions
> md4
> md5
> sha
> sha1
> sha224
> sha256
> sha384
> sha512
> ripemd160
> whirlpool
> These functions can be used to calculate a hash value for input strings of
> varying length, with a low probability of collision. Collision probability is
> reduced as digest length is increased by choosing an appropriate algorithm.
> Such hash values are useful when long varchars need to be stored as a key
> column and a low probability of collisions is acceptable. Storing the digest
> in the key instead of a varchar of say 4K bytes, allows several thousand
> bytes to be saved per row (since varchars fully expanded when they are stored
> in the key)
> UDFs can be written to compute these digests but they have a few deficiencies
> a) A different declaration is needed for input strings of different lengths
> b) Data has to be sent to the udrserv process and the answer received back,
> adding to messaging overhead
> These functions are available in the openssl library. This library is already
> linked by Trafodion source. Therefore no new dependency will be introduced.
> The library will be dynamically linked (with -l option) and therefore openssl
> binaries will not be shipped with Trafodion.
> The list of functions could be reduced or increased as necessary.
> There will be no PCode implementation for these functions.
> The output type will be fixed for each function and will be in binary format.
> For a user who wishes to display the functions converttohex function will
> have to be wrapped around the digest function.
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