Suggestion to add secp256k1_ec_pubkey_compress() function #259

1. 
   ufasoft commented at 12:22 pm on June 19, 2015: none

   The library has secp256k1_ec_pubkey_decompress() But symmetric operation _compress() does not exist.

   It is possible to export PrivKey to compressed PubKey form, but sometime PrivKey is not available.

   As I see the implementation is very simple: copy first 33 bytes and OR some bitmask.

2. 
   sipa commented at 12:26 pm on June 19, 2015: contributor

   Yes the reasoning for not having such a function is because it is trivial.

   However as the library is growing more into a fully-featured API rather than a collection of low-level routines, I think it makes sense to add it. On Jun 19, 2015 2:22 PM, “Ufasoft” notifications@github.com wrote:

   The library has secp256k1_ec_pubkey_decompress() But symmetric operation _compress() does not exist.

   It is possible to export PrivKey to compressed PubKey form, but sometime PrivKey is not available.

   As I see the implementation is very simple: copy first 33 bytes and OR some bitmask.

   — Reply to this email directly or view it on GitHub https://github.com/bitcoin/secp256k1/issues/259.

3. afk11 cross-referenced this on Jun 26, 2015 from issue Add secp256k1_ec_pubkey_compress() by afk11
4. 
   apoelstra commented at 9:02 pm on August 3, 2015: contributor

   Recommend close since the pubkey_t API now means that keys don’t have a un/compressedness until the time of serialization.
5. 
   ufasoft commented at 9:05 pm on August 3, 2015: none

   agree
6. ufasoft closed this on Aug 3, 2015

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ufasoft sipa apoelstra