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https://issues.apache.org/jira/browse/HBASE-10062?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13837335#comment-13837335
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Andrew Purtell edited comment on HBASE-10062 at 12/3/13 6:09 AM:
-----------------------------------------------------------------
We can deduce the encrypted data size by subtracting the encryption header size
from the remainder of the block on disk, the size of which is recorded in the
block header. I am testing a change locally that uses this as the block crypto
header:
{noformat}
// +--------------------------+
// | byte iv length |
// +--------------------------+
// | iv data ... |
// +--------------------------+
// | encrypted block data ... |
// +--------------------------+
{noformat}
We use an IV length of 0 to detect the special case where the block encoder is
required to encode a block length of zero. It happens (at least in unit tests).
Will submit to HadoopQA if all is well locally.
was (Author: apurtell):
We can deduce the encrypted data size by subtracting the encryption header size
from the remainder of the block on disk, the size of which is recorded in the
block header. I am testing a change locally that uses this as the block crypto
header:
{noformat}
// +--------------------------+
// | byte iv length |
// +--------------------------+
// | iv data ... |
// +--------------------------+
// | encrypted block data ... |
// +--------------------------+
{noformat}
We use an IV of 0 to detect the special case where the block encoder is
required to encode a block length of zero. It happens (at least in unit tests).
Will submit to HadoopQA if all is well locally.
> Reconsider storing plaintext length in the encrypted block header
> -----------------------------------------------------------------
>
> Key: HBASE-10062
> URL: https://issues.apache.org/jira/browse/HBASE-10062
> Project: HBase
> Issue Type: Improvement
> Reporter: Andrew Purtell
> Assignee: Andrew Purtell
> Priority: Minor
> Fix For: 0.98.0
>
> Attachments: 10062.patch
>
>
> After HBASE-7544, if an HFile belongs to an encrypted family, it is encrypted
> on a per block basis. The encrypted blocks include the following header:
> {noformat}
> // +--------------------------+
> // | vint plaintext length |
> // +--------------------------+
> // | vint iv length |
> // +--------------------------+
> // | iv data ... |
> // +--------------------------+
> // | encrypted block data ... |
> // +--------------------------+
> {noformat}
> The reason for storing the plaintext length is so we can create an decryption
> stream over the encrypted block data and, no matter the internal details of
> the crypto algorithm (whether it adds padding, etc.) after reading the
> expected plaintext bytes we know the reader is finished. However my colleague
> Jerry Chen pointed out today this construction mandates the block be
> processed exactly that way. Storing and using the encrypted data length
> instead could provide more implementation flexibility down the road.
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