HashInfoLib.py

#! /usr/bin/env python3


"""
This file is part of Bleichenbacher Signature Forger v2.2.
This is a library unit that provides ASN.1 paddings for hash algorithms.

Copyright 2016 Filippo Valsorda
Copyright 2017 Peter Hoeg Steffensen
Copyright 2021 Maxim Masiutin

Bleichenbacher Signature Forger is free software: you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation, either version 3 of the License,
or (at your option) any later version.

Bleichenbacher Signature Forger is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Bleichenbacher Signature Forger.
If not, see <https://www.gnu.org/licenses/>.
"""

from hashlib import md5, sha1, sha224, sha256, sha384, sha512

HASH_ASN1 = {
    "MD5": b"\x30\x20\x30\x0c\x06\x08\x2a\x86\x48\x86\xf7\x0d\x02\x05\x05\x00\x04\x10",
    "SHA-1": b"\x30\x21\x30\x09\x06\x05\x2b\x0e\x03\x02\x1a\x05\x00\x04\x14",
    "SHA-224": b"\x30\x51\x30\x0d\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x04\x05\x00\x04\x1C",
    "SHA-256": b"\x30\x31\x30\x0d\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x01\x05\x00\x04\x20",
    "SHA-384": b"\x30\x41\x30\x0d\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x02\x05\x00\x04\x30",
    "SHA-512": b"\x30\x51\x30\x0d\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x03\x05\x00\x04\x40",
}


class Hash:
    def __init__(self, hashAlg):
        if hashAlg == "MD5":
            self.digestInfo = HASH_ASN1[hashAlg]
            self.digester = md5
        elif hashAlg == "SHA-1":
            self.digestInfo = HASH_ASN1[hashAlg]
            self.digester = sha1
        elif hashAlg == "SHA-224":
            self.digestInfo = HASH_ASN1[hashAlg]
            self.digester = sha224
        elif hashAlg == "SHA-256":
            self.digestInfo = HASH_ASN1[hashAlg]
            self.digester = sha256
        elif hashAlg == "SHA-384":
            self.digestInfo = HASH_ASN1[hashAlg]
            self.digester = sha384
        elif hashAlg == "SHA-512":
            self.digestInfo = HASH_ASN1[hashAlg]
            self.digester = sha512
        else:
            raise Exception("Invalid hash algorithm identifier provided")