LevelDB 源码分析「三、高性能写操作」 | SF-Zhou's Blog

[SF-Zhou]

https://sf-zhou.github.io/leveldb/leveldb_03_write_batch_and_log.html

[suntzu93]

Thank you for the great article. I'm adding trying to use encrypt/decrypt for leveldb and my idea is encrypt data before write to file in env_posix.cc , method WriteUnbuffered(const char *data, size_t size) . But I don't know if encrypt " char *data " has any effect to Record Header , CRC32... . I greatly appreciate your comments on this matter.

[SF-Zhou]

@suntzu93
Thank you for the great article. I'm adding trying to use encrypt/decrypt for leveldb and my idea is encrypt data before write to file in env_posix.cc , method WriteUnbuffered(const char *data, size_t size) . But I don't know if encrypt " char *data " has any effect to Record Header , CRC32... . I greatly appreciate your comments on this matter.

I think it's ok if you do symmetrical decryption after PosixRandomAccessFile::Read. The position of reading and writing may need to be mapped according to the encryption algorithm.

[suntzu93]

@suntzu93
Thank you for the great article. I'm adding trying to use encrypt/decrypt for leveldb and my idea is encrypt data before write to file in env_posix.cc , method WriteUnbuffered(const char *data, size_t size) . But I don't know if encrypt " char *data " has any effect to Record Header , CRC32... . I greatly appreciate your comments on this matter.

I think it's ok if you do symmetrical decryption after PosixRandomAccessFile::Read. The position of reading and writing may need to be mapped according to the encryption algorithm.

Thanks for your answer, I'm doing with AES. I created a dex array from *data but only the first 5 bytes can be encrypted, the key and value cannot be encrypted. I'm using this library https://github.com/kokke/tiny-AES-c and it's working perfect with normal string. Do you have any idea about the type of "char *data"?

[SF-Zhou]

@suntzu93

@suntzu93
Thank you for the great article. I'm adding trying to use encrypt/decrypt for leveldb and my idea is encrypt data before write to file in env_posix.cc , method WriteUnbuffered(const char *data, size_t size) . But I don't know if encrypt " char *data " has any effect to Record Header , CRC32... . I greatly appreciate your comments on this matter.

I think it's ok if you do symmetrical decryption after PosixRandomAccessFile::Read. The position of reading and writing may need to be mapped according to the encryption algorithm.

Thanks for your answer, I'm doing with AES. I created a dex array from *data but only the first 5 bytes can be encrypted, the key and value cannot be encrypted. I'm using this library https://github.com/kokke/tiny-AES-c and it's working perfect with normal string. Do you have any idea about the type of "char *data"?

The data in WriteUnbuffered(const char *data, size_t size) is not a c string, but a byte stream. It can contain \0. For the AES algorithm, I have not used it before and may not be able to help.

[suntzu93]

Really thank you for your help, now I have a keywork to continue my work. Have a nice day bro.

[Stephan14]

看了一下代码，写入的时候好像是按照Record粒度来写入文件的，不是按照Block粒度来写入文件的，对吗？

[Stephan14]

当Record很小的时候，是按照Record来写入的；当Record很大的时候，是按照Block粒度来写入的，是这样的吗？

[SF-Zhou]

是的