Solr: Store SHA1-hashes efficient

I have to store, index and find a lot SHA1-Tokens in Solr.

Now I store them as 40-Chars-Hex-strings like 68ac906495480a3404beee4874ed853a037a7a8f. There are about 10,000+ unique SHA1-tokens in my Solr index.

Would it be better to store the values compressed as a 20-Byte BinaryField? (half size of index, more performance...?)

I have read about Krugle in the "Lucene in action"-book who 开发者_Python百科store just some characters in the middle of (compressed) MD5-strings. Would this be better to get maximum search performance?