<ul>
<li><p>Transactions themselves do not compress well, they are mostly
cryptographic hashes and signatures. You can save a couple of bytes
here and there by bit-packing, but generally speaking there's not a
lot of reason to introduce massive complexity for moderate savings. Many wallets today grind the signatures to save an
extra byte, but this is possible without changing any of the other
software in the network.</p>
<p>A good portion of the transactions (30%) are produced by wallets which do not use compressed ECDSA keys, which is a more obvious optimization to make. The majority of these are likely produced by blockchain.com wallets.</p>
</li>
<li><p>See above. Compression at the block level also does not present significant improvements. It is possible to compress ECDSA public keys (that are in the uncompressed format) before storing them on disk, but this is very computationally expensive.</p>
</li>
</ul>

CC BY-SA 4.0
2021-02-27T19:50:30.603Z
2021-02-27T19:50:30.603Z
Claris
<p>I have two similar questions</p>
<ul>
<li>Why aren't transactions compressed in the P2P layer (and why wasn't this discussed in the agenda)?</li>
<li>Why aren't transactions compressed before they're added to a block? (Effectively a block size increase) Are there reasons other than avoiding a hard fork?</li>
</ul>

CC BY-SA 4.0
2021-02-27T19:45:15.960Z
What agenda are you talking about?
Claris
CC BY-SA 4.0
2021-02-27T20:48:00.967Z
Any discussion today including bips and fork altcoins
MCCCS
CC BY-SA 4.0
2021-02-27T22:46:01.547Z
Asking about agendas is pointless - there isn't any entity that can set one. People, and organizations may have agendas, but those may conflict, or just go nowhere for unrelated reasons. In general the answer to questions like this, as stated, is simply "nobody has found it important enough to work on and/or push for". A more informative question would be asking about known difficulties or other limitations, rather than asking why it isn't done.
Pieter Wuille
<transactions>
Is there a reason transactions aren't compressed?
MCCCS
# Is there a reason transactions aren't compressed?

(Asked by: username_0 on 2021-02-27)

I have two similar questions

* Why aren't transactions compressed in the P2P layer (and why wasn't this discussed in the agenda)?
* Why aren't transactions compressed before they're added to a block? (Effectively a block size increase) Are there reasons other than avoiding a hard fork?

**Tags:** transactions

> **Comments:**
> **username_1**: What agenda are you talking about?  
> **username_0**: Any discussion today including bips and fork altcoins  
> **username_2**: Asking about agendas is pointless - there isn't any entity that can set one. People, and organizations may have agendas, but those may conflict, or just go nowhere for unrelated reasons. In general the answer to questions like this, as stated, is simply "nobody has found it important enough to work on and/or push for". A more informative question would be asking about known difficulties or other limitations, rather than asking why it isn't done.  

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## 1 answers

### Answer by username_1 on 2021-02-27. Score: 3 | Accepted answer

* Transactions themselves do not compress well, they are mostly
  cryptographic hashes and signatures. You can save a couple of bytes
  here and there by bit-packing, but generally speaking there's not a
  lot of reason to introduce massive complexity for moderate savings. Many wallets today grind the signatures to save an
  extra byte, but this is possible without changing any of the other
  software in the network.

  A good portion of the transactions (30%) are produced by wallets which do not use compressed ECDSA keys, which is a more obvious optimization to make. The majority of these are likely produced by blockchain.com wallets.
* See above. Compression at the block level also does not present significant improvements. It is possible to compress ECDSA public keys (that are in the uncompressed format) before storing them on disk, but this is very computationally expensive.


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