94 lines
3.9 KiB
Python
94 lines
3.9 KiB
Python
from binascii import hexlify
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import pyelliptic
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from pyelliptic import arithmetic as a, OpenSSL
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def makeCryptor(privkey):
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private_key = a.changebase(privkey, 16, 256, minlen=32)
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public_key = pointMult(private_key)
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privkey_bin = '\x02\xca\x00\x20' + private_key
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pubkey_bin = '\x02\xca\x00\x20' + public_key[1:-32] + '\x00\x20' + public_key[-32:]
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cryptor = pyelliptic.ECC(curve='secp256k1',privkey=privkey_bin,pubkey=pubkey_bin)
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return cryptor
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def hexToPubkey(pubkey):
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pubkey_raw = a.changebase(pubkey[2:],16,256,minlen=64)
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pubkey_bin = '\x02\xca\x00 '+pubkey_raw[:32]+'\x00 '+pubkey_raw[32:]
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return pubkey_bin
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def makePubCryptor(pubkey):
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pubkey_bin = hexToPubkey(pubkey)
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return pyelliptic.ECC(curve='secp256k1',pubkey=pubkey_bin)
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# Converts hex private key into hex public key
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def privToPub(privkey):
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private_key = a.changebase(privkey, 16, 256, minlen=32)
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public_key = pointMult(private_key)
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return hexlify(public_key)
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# Encrypts message with hex public key
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def encrypt(msg,hexPubkey):
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return pyelliptic.ECC(curve='secp256k1').encrypt(msg,hexToPubkey(hexPubkey))
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# Decrypts message with hex private key
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def decrypt(msg,hexPrivkey):
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return makeCryptor(hexPrivkey).decrypt(msg)
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# Decrypts message with an existing pyelliptic.ECC.ECC object
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def decryptFast(msg,cryptor):
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return cryptor.decrypt(msg)
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# Signs with hex private key
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def sign(msg,hexPrivkey):
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# pyelliptic is upgrading from SHA1 to SHA256 for signing. We must
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# upgrade PyBitmessage gracefully.
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# https://github.com/yann2192/pyelliptic/pull/33
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# More discussion: https://github.com/yann2192/pyelliptic/issues/32
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return makeCryptor(hexPrivkey).sign(msg, digest_alg=OpenSSL.EVP_ecdsa) # SHA1
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#return makeCryptor(hexPrivkey).sign(msg, digest_alg=OpenSSL.EVP_sha256) # SHA256. We should switch to this eventually.
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# Verifies with hex public key
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def verify(msg,sig,hexPubkey):
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# As mentioned above, we must upgrade gracefully to use SHA256. So
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# let us check the signature using both SHA1 and SHA256 and if one
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# of them passes then we will be satisfied. Eventually this can
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# be simplified and we'll only check with SHA256.
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try:
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sigVerifyPassed = makePubCryptor(hexPubkey).verify(sig,msg,digest_alg=OpenSSL.EVP_ecdsa) # old SHA1 algorithm.
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except:
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sigVerifyPassed = False
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if sigVerifyPassed:
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# The signature check passed using SHA1
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return True
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# The signature check using SHA1 failed. Let us try it with SHA256.
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try:
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return makePubCryptor(hexPubkey).verify(sig,msg,digest_alg=OpenSSL.EVP_sha256)
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except:
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return False
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# Does an EC point multiplication; turns a private key into a public key.
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def pointMult(secret):
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while True:
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try:
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"""
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Evidently, this type of error can occur very rarely:
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File "highlevelcrypto.py", line 54, in pointMult
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group = OpenSSL.EC_KEY_get0_group(k)
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WindowsError: exception: access violation reading 0x0000000000000008
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"""
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k = OpenSSL.EC_KEY_new_by_curve_name(OpenSSL.get_curve('secp256k1'))
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priv_key = OpenSSL.BN_bin2bn(secret, 32, None)
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group = OpenSSL.EC_KEY_get0_group(k)
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pub_key = OpenSSL.EC_POINT_new(group)
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OpenSSL.EC_POINT_mul(group, pub_key, priv_key, None, None, None)
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OpenSSL.EC_KEY_set_private_key(k, priv_key)
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OpenSSL.EC_KEY_set_public_key(k, pub_key)
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size = OpenSSL.i2o_ECPublicKey(k, None)
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mb = OpenSSL.create_string_buffer(size)
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OpenSSL.i2o_ECPublicKey(k, OpenSSL.byref(OpenSSL.pointer(mb)))
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OpenSSL.EC_POINT_free(pub_key)
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OpenSSL.BN_free(priv_key)
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OpenSSL.EC_KEY_free(k)
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return mb.raw
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except Exception as e:
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import traceback
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import time
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traceback.print_exc()
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time.sleep(0.2)
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