The old PyBtcEngine project (the precursor to Armory), had a pure-python implementation of all the ECDSA math. Granted, that was based on an old post by Russian forum user "Lis", in which he released the pure-python-ECDSA code to public domain. I just wrapped it up.
If you clone the
PyBtcEngine project, you will probably only need to to "from pybtcengine import *" and then run the relevant calls. Here's some sample code that showing how to convert private key to address in the first four lines (in bold). Then it does a ton more. This is in unittest.py, where I created a private key ('aa'*32) and an empty transaction and tested signing then verifying it.
print 'Testing PyCreateAndSignTx'
AddrA = PyBtcAddress().createFromPrivateKey(hex_to_int('aa'*32))
AddrB = PyBtcAddress().createFromPrivateKey(hex_to_int('bb'*32))
print ' Address A:', AddrA.getAddrStr()
print ' Address B:', AddrB.getAddrStr()
# This TxIn will be completely ignored, so it can contain garbage
txinA = PyTxIn()
txinA.outpoint = PyOutPoint().unserialize(hex_to_binary('00'*36))
txinA.binScript = hex_to_binary('99'*4)
txinA.sequence = hex_to_binary('ff'*4)
txoutA = PyTxOut()
txoutA.value = 50 * (10**8 )
txoutA.binScript = '\x76\xa9\x14' + AddrA.getAddr160() + '\x88\xac'
tx1 = PyTx()
tx1.version = 1
tx1.numInputs = 1
tx1.inputs = [txinA]
tx1.numOutputs = 1
tx1.outputs = [txoutA]
tx1.locktime = 0
tx1hash = tx1.getHash()
print 'Creating transaction to send coins from A to B'
tx2 = PyCreateAndSignTx( [[ AddrA, tx1, 0 ]], [[AddrB, 50*(10**8 )]])
print 'Verifying the transaction we just created',
psp = PyScriptProcessor()
psp.setTxObjects(tx1, tx2, 0)
verifResult = psp.verifyTransactionValid()
More than you asked for... but maybe you'll be interested in all of it later
Btw, Armory has the same functionality, but I outsourced all the crypto to C++, where it's a hell of a lot faster. If you want to use the latest, you can do that, but it will require compiling... but the crypto itself hasn't really changed.
