user77140: I have read that private key is 256 bits or 32 byte. see here
I generated a key on bitcoin-test network. 
WIF:

cVe4tA6QHduboeSiQD6Y6nzV1QjaVpDVG2YHbqbtJiSCxsNDYYUF

HEX:

f06e4a9c228dafff48e6a44eb9527a14374a203a5750de01c0cf39e7280ce45501

if you notice above hex is 33 bytes!
I went  on to sign a transaction :

01000000015760c907060ca47bbf97a964a435387c38fd86c307e920c1d29ce1a3d0d4d56b010000001976a914ca560954433f0fd1bda9bb566607d1724559b0db88acffffffff02d0070000000000001976a914f9ad22432bb6eb5e4262f9e4bcfb09fda2f5167b88ace068be07000000001976a914ca560954433f0fd1bda9bb566607d1724559b0db88ac0000000001000000

generated the following tx hash:

01000000015760c907060ca47bbf97a964a435387c38fd86c307e920c1d29ce1a3d0d4d56b010000006b483045022100f2224f424a63675682f062fbf6699028727e13d26dc382af6dca57dfb21e9910022011b485e63f8f0045c40f8df41bcab13040bc554da4c176a380c81d18c615b210012103b9dc990c2b8a999ba68bf80cbff94fd85d62a01c7dc48252156f78c813b0aa67ffffffff02d0070000000000001976a914f9ad22432bb6eb5e4262f9e4bcfb09fda2f5167b88ace068be07000000001976a914ca560954433f0fd1bda9bb566607d1724559b0db88ac00000000

and when i broadcasted it got accepted!
Now my question is, how can 33 byte private key be valid signing key?
P.S. please don't take out the coins, they are worthless and i need for testing. thanks!

user77140: Got it: the last byte 01 stands for compression and has to be dropped

77140: <p>I have read that private key is 256 bits or 32 byte. <a href="https://en.bitcoinwiki.org/wiki/Private_key" rel="nofollow noreferrer">see here</a></p>

<p>I generated a key on bitcoin-test network. </p>

<p>WIF:</p>

<blockquote>
  <p>cVe4tA6QHduboeSiQD6Y6nzV1QjaVpDVG2YHbqbtJiSCxsNDYYUF</p>
</blockquote>

<p>HEX:</p>

<blockquote>
  <p>f06e4a9c228dafff48e6a44eb9527a14374a203a5750de01c0cf39e7280ce45501</p>
</blockquote>

<p>if you notice above hex is 33 bytes!</p>

<p>I went  on to sign a transaction :</p>

<blockquote>
  <p>01000000015760c907060ca47bbf97a964a435387c38fd86c307e920c1d29ce1a3d0d4d56b010000001976a914ca560954433f0fd1bda9bb566607d1724559b0db88acffffffff02d0070000000000001976a914f9ad22432bb6eb5e4262f9e4bcfb09fda2f5167b88ace068be07000000001976a914ca560954433f0fd1bda9bb566607d1724559b0db88ac0000000001000000</p>
</blockquote>

<p>generated the following tx hash:</p>

<blockquote>
  <p>01000000015760c907060ca47bbf97a964a435387c38fd86c307e920c1d29ce1a3d0d4d56b010000006b483045022100f2224f424a63675682f062fbf6699028727e13d26dc382af6dca57dfb21e9910022011b485e63f8f0045c40f8df41bcab13040bc554da4c176a380c81d18c615b210012103b9dc990c2b8a999ba68bf80cbff94fd85d62a01c7dc48252156f78c813b0aa67ffffffff02d0070000000000001976a914f9ad22432bb6eb5e4262f9e4bcfb09fda2f5167b88ace068be07000000001976a914ca560954433f0fd1bda9bb566607d1724559b0db88ac00000000</p>
</blockquote>

<p>and when i broadcasted it got <a href="https://live.blockcypher.com/btc-testnet/address/n4H7xNPyAkUwc6MELoAHT47V8z69ektmcd/" rel="nofollow noreferrer">accepted</a>!</p>

<p>Now my question is, how can 33 byte private key be valid signing key?</p>

<p>P.S. please don't take out the coins, they are worthless and i need for testing. thanks!</p>
 77140: <p>Got it: the last byte 01 stands for compression and has to be dropped</p>
