From 821a3b9f1f80e0858cb1e4729a45ef371b21ba12 Mon Sep 17 00:00:00 2001 From: vtexier Date: Sun, 17 Feb 2019 18:00:49 +0100 Subject: [PATCH] [enh] #78 Add Ascii Armor encrypted and signed message creation and example --- duniterpy/key/__init__.py | 5 +- duniterpy/key/ascii_armor.py | 123 ++++++++++++++++++ .../save_ascii_armor_encrypted_message.py | 35 +++++ 3 files changed, 161 insertions(+), 2 deletions(-) create mode 100644 duniterpy/key/ascii_armor.py create mode 100644 examples/save_ascii_armor_encrypted_message.py diff --git a/duniterpy/key/__init__.py b/duniterpy/key/__init__.py index 1f2e92d..05cc9c2 100644 --- a/duniterpy/key/__init__.py +++ b/duniterpy/key/__init__.py @@ -1,3 +1,4 @@ -from .signing_key import SigningKey, ScryptParams +from .signing_key import SigningKey from .verifying_key import VerifyingKey -from .encryption_key import SecretKey, PublicKey +from .encryption_key import SecretKey, PublicKey, SCRYPT_PARAMS, SEED_LENGTH +from .ascii_armor import AsciiArmor diff --git a/duniterpy/key/ascii_armor.py b/duniterpy/key/ascii_armor.py new file mode 100644 index 0000000..a6b5d57 --- /dev/null +++ b/duniterpy/key/ascii_armor.py @@ -0,0 +1,123 @@ +import base64 +import libnacl +from typing import Optional, List + +from duniterpy.key import SigningKey, PublicKey, SCRYPT_PARAMS, SEED_LENGTH + +# Headers constants +BEGIN_MESSAGE_HEADER = "-----BEGIN DUNITER MESSAGE-----" +END_MESSAGE_HEADER = "-----END DUNITER MESSAGE-----" +BEGIN_SIGNATURE_HEADER = "-----BEGIN DUNITER SIGNATURE-----" +END_SIGNATURE_HEADER = "-----END DUNITER SIGNATURE-----" + +# Version field values +AA_MESSAGE_VERSION = "Python Libnacl " + libnacl.__version__ +AA_SIGNATURE_VERSION = "Python Libnacl " + libnacl.__version__ + + +class AsciiArmor: + """ + Class to handle writing and reading of ascii armor messages + """ + + @staticmethod + def encrypt(message: str, pubkey: str, signing_keys: Optional[List[SigningKey]] = None, + message_comment: Optional[str] = None, signatures_comment: Optional[str] = None) -> str: + """ + Encrypt a message in ascii armor format, optionally signing it + + :param message: Utf-8 message + :param pubkey: Public key of recipient for encryption + :param signing_keys: Optional list of SigningKey instances + :param message_comment: Optional message comment field + :param signatures_comment: Optional signatures comment field + :return: + """ + pubkey_instance = PublicKey(pubkey) + base64_encrypted_message = base64.b64encode(pubkey_instance.encrypt_seal(message)) # type: bytes + script_field = AsciiArmor._get_scrypt_field() + + # create block with headers + ascii_armor_msg = """ +{begin_message_header} +Version: {version} +{script_field} +""".format(begin_message_header=BEGIN_MESSAGE_HEADER, version=AA_MESSAGE_VERSION, + script_field=script_field) + + # add message comment if specified + if message_comment: + ascii_armor_msg += AsciiArmor._get_comment_field(message_comment) + + # add encrypted message + ascii_armor_msg += """ +{base64_encrypted_message} +""".format(base64_encrypted_message=base64_encrypted_message.decode('utf-8')) + + # if no signature... + if signing_keys is None: + # add message tail + ascii_armor_msg += END_MESSAGE_HEADER + else: + # add signature blocks and close block on last signature + count = 1 + for signing_key in signing_keys: + ascii_armor_msg += AsciiArmor._get_signature_block(message, signing_key, count == len(signing_keys), + signatures_comment) + count += 1 + + return ascii_armor_msg + + @staticmethod + def _get_scrypt_field(): + """ + Return the Scrypt field + + :return: + """ + return "Scrypt: N={0};r={1};p={2};len={3}".format(SCRYPT_PARAMS['N'], SCRYPT_PARAMS['r'], SCRYPT_PARAMS['p'], + SEED_LENGTH) + + @staticmethod + def _get_comment_field(comment: str) -> str: + """ + Return a comment field + + :param comment: Comment text + :return: + """ + return "Comment: {comment}\n".format(comment=comment) + + @staticmethod + def _get_signature_block(message: str, signing_key: SigningKey, close_block: bool = True, + comment: Optional[str] = None) -> str: + """ + Return a signature block + + :param message: Message (not encrypted!) to sign + :param signing_key: The libnacl SigningKey instance of the keypair + :param close_block: Optional flag to close the signature block with the signature tail header + :param comment: Optional comment field content + :return: + """ + script_param_field = AsciiArmor._get_scrypt_field() + base64_signature = base64.b64encode(signing_key.signature(message)) + + block = """{begin_signature_header} +Version: {version} +Scrypt: {script_params} +""".format(begin_signature_header=BEGIN_SIGNATURE_HEADER, version=AA_SIGNATURE_VERSION, + script_params=script_param_field) + + # add message comment if specified + if comment: + block += AsciiArmor._get_comment_field(comment) + + block += """ +{base64_signature} +""".format(base64_signature=base64_signature.decode('utf-8')) + + if close_block: + block += END_SIGNATURE_HEADER + + return block diff --git a/examples/save_ascii_armor_encrypted_message.py b/examples/save_ascii_armor_encrypted_message.py new file mode 100644 index 0000000..abbc626 --- /dev/null +++ b/examples/save_ascii_armor_encrypted_message.py @@ -0,0 +1,35 @@ +import getpass +from duniterpy import __version__ + +from duniterpy.key import AsciiArmor, SigningKey + +################################################ + +AA_ENCRYPTED_MESSAGE_FILENAME = 'duniter_aa_encrypted_message.txt' + +if __name__ == '__main__': + # Ask public key of the recipient + pubkeyBase58 = input("Enter public key of the message recipient: ") + + # prompt hidden user entry + salt = getpass.getpass("Enter your passphrase (salt): ") + + # prompt hidden user entry + password = getpass.getpass("Enter your password: ") + + # init SigningKey instance + signing_key = SigningKey.from_credentials(salt, password) + + # Enter the message + message = input("Enter your message: ") + + comment = "generated by Duniterpy {0}".format(__version__) + # Encrypt the message, only the recipient secret key will be able to decrypt the message + encrypted_message = AsciiArmor.encrypt(message, pubkeyBase58, [signing_key], message_comment=comment, + signatures_comment=comment) + + # Save encrypted message in a file + with open(AA_ENCRYPTED_MESSAGE_FILENAME, 'w') as file_handler: + file_handler.write(encrypted_message) + + print("Ascii Armor Encrypted message saved in file ./{0}".format(AA_ENCRYPTED_MESSAGE_FILENAME)) -- GitLab