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https://issues.apache.org/jira/browse/HDFS-6606?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14131300#comment-14131300
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Srikanth Upputuri commented on HDFS-6606:
-----------------------------------------

This is a very nice effort. It's a great deal of learning for me reading 
through this jira and HDFS-3637. But I have a couple of fundamental questions 
here.

Does this patch improve data transfer speed? But isn't the existing RC4 option 
much faster (as shown in the comparison analysis)?

Does this patch improve the data transfer channel confidentiality? But, if we 
transfer the AES keys and IVs over a 3DES encrypted channel, isn't the overall 
confidentiality effectively same as someone who can successfully intercept and 
decrypt the 3DES traffic can read the AES keys?

Am I missing something here?

> Optimize HDFS Encrypted Transport performance
> ---------------------------------------------
>
>                 Key: HDFS-6606
>                 URL: https://issues.apache.org/jira/browse/HDFS-6606
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: datanode, hdfs-client, security
>            Reporter: Yi Liu
>            Assignee: Yi Liu
>         Attachments: HDFS-6606.001.patch, HDFS-6606.002.patch, 
> HDFS-6606.003.patch, HDFS-6606.004.patch, 
> OptimizeHdfsEncryptedTransportperformance.pdf
>
>
> In HDFS-3637, [~atm] added support for encrypting the DataTransferProtocol, 
> it was a great work.
> It utilizes SASL {{Digest-MD5}} mechanism (use Qop: auth-conf),  it supports 
> three security strength:
> * high                      3des   or rc4 (128bits)
> * medium             des or rc4(56bits)
> * low                       rc4(40bits)
> 3des and rc4 are slow, only *tens of MB/s*, 
> http://www.javamex.com/tutorials/cryptography/ciphers.shtml
> http://www.cs.wustl.edu/~jain/cse567-06/ftp/encryption_perf/
> I will give more detailed performance data in future. Absolutely it’s 
> bottleneck and will vastly affect the end to end performance. 
> AES(Advanced Encryption Standard) is recommended as a replacement of DES, 
> it’s more secure; with AES-NI support, the throughput can reach nearly 
> *2GB/s*, it won’t be the bottleneck any more, AES and CryptoCodec work is 
> supported in HADOOP-10150, HADOOP-10603 and HADOOP-10693 (We may need to add 
> a new mode support for AES). 
> This JIRA will use AES with AES-NI support as encryption algorithm for 
> DataTransferProtocol.



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