68 lines
1.5 KiB
Python
68 lines
1.5 KiB
Python
import base64
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import binascii
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try:
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from cryptography.hazmat.primitives.asymmetric.utils import (
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decode_rfc6979_signature, encode_rfc6979_signature
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)
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except ImportError:
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pass
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def base64url_decode(input):
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rem = len(input) % 4
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if rem > 0:
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input += b'=' * (4 - rem)
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return base64.urlsafe_b64decode(input)
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def base64url_encode(input):
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return base64.urlsafe_b64encode(input).replace(b'=', b'')
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def merge_dict(original, updates):
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if not updates:
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return original
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try:
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merged_options = original.copy()
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merged_options.update(updates)
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except (AttributeError, ValueError) as e:
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raise TypeError('original and updates must be a dictionary: %s' % e)
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return merged_options
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def number_to_bytes(num, num_bytes):
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padded_hex = '%0*x' % (2 * num_bytes, num)
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big_endian = binascii.a2b_hex(padded_hex.encode('ascii'))
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return big_endian
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def bytes_to_number(string):
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return int(binascii.b2a_hex(string), 16)
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def der_to_raw_signature(der_sig, curve):
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num_bits = curve.key_size
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num_bytes = (num_bits + 7) // 8
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r, s = decode_rfc6979_signature(der_sig)
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return number_to_bytes(r, num_bytes) + number_to_bytes(s, num_bytes)
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def raw_to_der_signature(raw_sig, curve):
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num_bits = curve.key_size
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num_bytes = (num_bits + 7) // 8
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if len(raw_sig) != 2 * num_bytes:
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raise ValueError('Invalid signature')
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r = bytes_to_number(raw_sig[:num_bytes])
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s = bytes_to_number(raw_sig[num_bytes:])
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return encode_rfc6979_signature(r, s)
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