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38 lines
1.2 KiB
Plaintext
38 lines
1.2 KiB
Plaintext
# Cryptography
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The section documents the cryptographic algorithms and Python implementations that we use.
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The implementations that we have chosen for now are just for fast prototyping. Some of them are pure Python implementations which may be slow. As future work, we should look at other alternatives.
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## Hashes
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For hashing we are using the sha3-256 algorithm and [pysha3](https://bitbucket.org/tiran/pykeccak) as the Python implementation. We store the hex encoded hash in the database. For example:
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```python
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import hashlib
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# monkey patch hashlib with sha3 functions
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import sha3
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data = "message"
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tx_hash = hashlib.sha3_256(data).hexdigest()
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```
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## Keys
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For signing and veryfing signatures we are using the ECDSA with 192bit key lengths and
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[python-ecdsa](https://github.com/warner/python-ecdsa) as the python implementation.
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The public-key or verification key are converted to string and hex encoded before storing them to the blockchain. For example:
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```python
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import binascii
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from ecdsa import SigningKey
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# generate signing key in hex encoded form
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sk = SigningKey.generate()
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sk_hex = binascii.hexlify(sk.to_string())
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# get signing key from hex
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sk = SigningKey.from_string(binascii.unhexlify(sk_hex))
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```
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