M2Crypto.RSA — M2Crypto documentation

# Source code for M2Crypto.RSA

    from __future__ import absolute_import

    """M2Crypto wrapper for OpenSSL RSA API.

    Copyright (c) 1999-2004 Ng Pheng Siong. All rights reserved."""

    import sys

    from M2Crypto import BIO, Err, m2, util
    if util.py27plus:
        from typing import Any, AnyStr, Callable, Dict, List, IO, Optional, Tuple  # noqa

    class RSAError(Exception):
        pass

    m2.rsa_init(RSAError)

    no_padding = m2.no_padding
    pkcs1_padding = m2.pkcs1_padding
    sslv23_padding = m2.sslv23_padding
    pkcs1_oaep_padding = m2.pkcs1_oaep_padding

    class RSA:
        """
        RSA Key Pair.
        """

        m2_rsa_free = m2.rsa_free

        def __init__(self, rsa, _pyfree=0):
            # type: (bytes, int) -> None
            """
            :param rsa: binary representation of OpenSSL RSA type
            """
            assert m2.rsa_type_check(rsa), "'rsa' type error"
            self.rsa = rsa
            self._pyfree = _pyfree

        def __del__(self):
            # type: () -> None
            if getattr(self, '_pyfree', 0):
                self.m2_rsa_free(self.rsa)

        def __len__(self):
            # type: () -> int
            return m2.rsa_size(self.rsa) << 3

        def __getattr__(self, name):
            # type: (str) -> bytes
            if name == 'e':
                return m2.rsa_get_e(self.rsa)
            elif name == 'n':
                return m2.rsa_get_n(self.rsa)
            else:
                raise AttributeError

        def pub(self):
            # type: () -> Tuple[bytes, bytes]
            assert self.check_key(), 'key is not initialised'
            return m2.rsa_get_e(self.rsa), m2.rsa_get_n(self.rsa)

        def public_encrypt(self, data, padding):
            # type: (bytes, int) -> bytes
            assert self.check_key(), 'key is not initialised'
            return m2.rsa_public_encrypt(self.rsa, data, padding)

        def public_decrypt(self, data, padding):
            # type: (bytes, int) -> bytes
            assert self.check_key(), 'key is not initialised'
            return m2.rsa_public_decrypt(self.rsa, data, padding)

        def private_encrypt(self, data, padding):
            # type: (bytes, int) -> bytes
            assert self.check_key(), 'key is not initialised'
            return m2.rsa_private_encrypt(self.rsa, data, padding)

        def private_decrypt(self, data, padding):
            # type: (bytes, int) -> bytes
            assert self.check_key(), 'key is not initialised'
            return m2.rsa_private_decrypt(self.rsa, data, padding)

        def save_key_bio(self, bio, cipher='aes_128_cbc',
                         callback=util.passphrase_callback):
            # type: (BIO.BIO, Optional[str], Callable) -> int
            """
            Save the key pair to an M2Crypto.BIO.BIO object in PEM format.

            :param bio: M2Crypto.BIO.BIO object to save key to.

            :param cipher: Symmetric cipher to protect the key. The default
                           cipher is 'aes_128_cbc'. If cipher is None, then
                           the key is saved in the clear.

            :param callback: A Python callable object that is invoked
                             to acquire a passphrase with which to protect
                             the key.  The default is
                             util.passphrase_callback.
            """
            if cipher is None:
                return m2.rsa_write_key_no_cipher(self.rsa, bio._ptr(), callback)
            else:
                ciph = getattr(m2, cipher, None)
                if ciph is None:
                    raise RSAError('not such cipher %s' % cipher)
                else:
                    ciph = ciph()
                return m2.rsa_write_key(self.rsa, bio._ptr(), ciph, callback)

        def save_key(self, file, cipher='aes_128_cbc',
                     callback=util.passphrase_callback):
            # type: (AnyStr, Optional[str], Callable) -> int
            """
            Save the key pair to a file in PEM format.

            :param file: Name of file to save key to.

            :param cipher: Symmetric cipher to protect the key. The default
                           cipher is 'aes_128_cbc'. If cipher is None, then
                           the key is saved in the clear.

            :param callback: A Python callable object that is invoked
                             to acquire a passphrase with which to protect
                             the key.  The default is
                             util.passphrase_callback.
            """
            with BIO.openfile(file, 'wb') as bio:
                return self.save_key_bio(bio, cipher, callback)

        save_pem = save_key

        def as_pem(self, cipher='aes_128_cbc', callback=util.passphrase_callback):
            # type: (Optional[str], Callable) -> bytes
            """
            Returns the key(pair) as a string in PEM format.
            """
            bio = BIO.MemoryBuffer()
            self.save_key_bio(bio, cipher, callback)
            return bio.read()

        def save_key_der_bio(self, bio):
            # type: (BIO.BIO) -> int
            """
            Save the key pair to an M2Crypto.BIO.BIO object in DER format.

            :param bio: M2Crypto.BIO.BIO object to save key to.
            """
            return m2.rsa_write_key_der(self.rsa, bio._ptr())

        def save_key_der(self, file):
            # type: (AnyStr) -> int
            """
            Save the key pair to a file in DER format.

            :param file: Filename to save key to
            """
            with BIO.openfile(file, 'wb') as bio:
                return self.save_key_der_bio(bio)

        def save_pub_key_bio(self, bio):
            # type: (BIO.BIO) -> int
            """
            Save the public key to an M2Crypto.BIO.BIO object in PEM format.

            :param bio: M2Crypto.BIO.BIO object to save key to.
            """
            return m2.rsa_write_pub_key(self.rsa, bio._ptr())

        def save_pub_key(self, file):
            # type: (AnyStr) -> int
            """
            Save the public key to a file in PEM format.

            :param file: Name of file to save key to.
            """
            with BIO.openfile(file, 'wb') as bio:
                return m2.rsa_write_pub_key(self.rsa, bio._ptr())

        def check_key(self):
            # type: () -> int
            """

            :return: returns 1 if rsa is a valid RSA key, and 0 otherwise.
                     -1 is returned if an error occurs while checking the key.
                     If the key is invalid or an error occurred, the reason
                     code can be obtained using ERR_get_error(3).
            """
            return m2.rsa_check_key(self.rsa)

        def sign_rsassa_pss(self, digest, algo='sha1', salt_length=20):
            # type: (bytes, str, int) -> bytes
            """
            Signs a digest with the private key using RSASSA-PSS

            :param digest: A digest created by using the digest method

            :param salt_length: The length of the salt to use

            :param algo: The hash algorithm to use
                         Legal values like 'sha1','sha224', 'sha256',
                         'ripemd160', and 'md5'.

            :return: a string which is the signature
            """
            hash = getattr(m2, algo, None)

            if hash is None:
                raise RSAError('not such hash algorithm %s' % algo)

            signature = m2.rsa_padding_add_pkcs1_pss(self.rsa, digest, hash(), salt_length)

            return self.private_encrypt(signature, m2.no_padding)

        def verify_rsassa_pss(self, data, signature, algo='sha1', salt_length=20):
            # type: (bytes, bytes, str, int) -> int
            """
            Verifies the signature RSASSA-PSS

            :param data: Data that has been signed

            :param signature: The signature signed with RSASSA-PSS

            :param salt_length: The length of the salt that was used

            :param algo: The hash algorithm to use
                         Legal values are for example 'sha1','sha224',
                         'sha256', 'ripemd160', and 'md5'.

            :return: 1 or 0, depending on whether the signature was
                     verified or not.
            """
            hash = getattr(m2, algo, None)

            if hash is None:
                raise RSAError('not such hash algorithm %s' % algo)

            plain_signature = self.public_decrypt(signature, m2.no_padding)

            return m2.rsa_verify_pkcs1_pss(self.rsa, data, plain_signature, hash(), salt_length)

        def sign(self, digest, algo='sha1'):
            # type: (bytes, str) -> bytes
            """
            Signs a digest with the private key

            :param digest: A digest created by using the digest method

            :param algo: The method that created the digest.
                         Legal values like 'sha1','sha224', 'sha256',
                         'ripemd160', and 'md5'.

            :return: a string which is the signature
            """
            digest_type = getattr(m2, 'NID_' + algo, None)
            if digest_type is None:
                raise ValueError('unknown algorithm', algo)

            return m2.rsa_sign(self.rsa, digest, digest_type)

        def verify(self, data, signature, algo='sha1'):
            # type: (bytes, bytes, str) -> int
            """
            Verifies the signature with the public key

            :param data: Data that has been signed

            :param signature: The signature signed with the private key

            :param algo: The method use to create digest from the data
                         before it was signed.  Legal values like
                         'sha1','sha224', 'sha256', 'ripemd160', and 'md5'.

            :return: 1 or 0, depending on whether the signature was
                     verified or not.
            """
            digest_type = getattr(m2, 'NID_' + algo, None)
            if digest_type is None:
                raise ValueError('unknown algorithm', algo)

            return m2.rsa_verify(self.rsa, data, signature, digest_type)

    class RSA_pub(RSA):  # noqa

        """
        Object interface to an RSA public key.
        """

        def __setattr__(self, name, value):
            # type: (str, bytes) -> None
            if name in ['e', 'n']:
                raise RSAError('use factory function new_pub_key() to set (e, n)')
            else:
                self.__dict__[name] = value

        def private_encrypt(self, *argv):
            # type: (*Any) -> None
            raise RSAError('RSA_pub object has no private key')

        def private_decrypt(self, *argv):
            # type: (*Any) -> None
            raise RSAError('RSA_pub object has no private key')

        def save_key(self, file, *args, **kw):
            # type: (AnyStr, *Any, **Any) -> int
            """
            Save public key to file.
            """
            return self.save_pub_key(file)

        def save_key_bio(self, bio, *args, **kw):
            # type: (BIO.BIO, *Any, **Any) -> int
            """
            Save public key to BIO.
            """
            return self.save_pub_key_bio(bio)

        # save_key_der

        # save_key_der_bio

        def check_key(self):
            # type: () -> int
            return m2.rsa_check_pub_key(self.rsa)

    def rsa_error():
        # type: () -> None
        raise RSAError(Err.get_error_message())

    def keygen_callback(p, n, out=sys.stdout):
        # type: (int, Any, IO[str]) -> None
        """
        Default callback for gen_key().
        """
        ch = ['.', '+', '*', '\n']
        out.write(ch[p])
        out.flush()

    def gen_key(bits, e, callback=keygen_callback):
        # type: (int, int, Callable) -> RSA
        """
        Generate an RSA key pair.

        :param bits: Key length, in bits.

        :param e: The RSA public exponent.

        :param callback: A Python callable object that is invoked
                         during key generation; its usual purpose is to
                         provide visual feedback. The default callback is
                         keygen_callback.

        :return: M2Crypto.RSA.RSA object.
        """
        return RSA(m2.rsa_generate_key(bits, e, callback), 1)

    def load_key(file, callback=util.passphrase_callback):
        # type: (AnyStr, Callable) -> RSA
        """
        Load an RSA key pair from file.

        :param file: Name of file containing RSA public key in PEM format.

        :param callback: A Python callable object that is invoked
                         to acquire a passphrase with which to unlock the
                         key.  The default is util.passphrase_callback.

        :return: M2Crypto.RSA.RSA object.
        """
        with BIO.openfile(file) as bio:
            return load_key_bio(bio, callback)

    def load_key_bio(bio, callback=util.passphrase_callback):
        # type: (BIO.BIO, Callable) -> RSA
        """
        Load an RSA key pair from an M2Crypto.BIO.BIO object.

        :param bio: M2Crypto.BIO.BIO object containing RSA key pair in PEM
                    format.

        :param callback: A Python callable object that is invoked
                         to acquire a passphrase with which to unlock the
                         key.  The default is util.passphrase_callback.

        :return: M2Crypto.RSA.RSA object.
        """
        rsa = m2.rsa_read_key(bio._ptr(), callback)
        if rsa is None:
            rsa_error()
        return RSA(rsa, 1)

    def load_key_string(string, callback=util.passphrase_callback):
        # type: (AnyStr, Callable) -> RSA
        """
        Load an RSA key pair from a string.

        :param string: String containing RSA key pair in PEM format.

        :param callback: A Python callable object that is invoked
                         to acquire a passphrase with which to unlock the
                         key. The default is util.passphrase_callback.

        :return: M2Crypto.RSA.RSA object.
        """
        bio = BIO.MemoryBuffer(string)
        return load_key_bio(bio, callback)

    def load_pub_key(file):
        # type: (AnyStr) -> RSA_pub
        """
        Load an RSA public key from file.

        :param file: Name of file containing RSA public key in PEM format.

        :return: M2Crypto.RSA.RSA_pub object.
        """
        with BIO.openfile(file) as bio:
            return load_pub_key_bio(bio)

    def load_pub_key_bio(bio):
        # type: (BIO.BIO) -> RSA_pub
        """
        Load an RSA public key from an M2Crypto.BIO.BIO object.

        :param bio: M2Crypto.BIO.BIO object containing RSA public key in PEM
                    format.

        :return: M2Crypto.RSA.RSA_pub object.
        """
        rsa = m2.rsa_read_pub_key(bio._ptr())
        if rsa is None:
            rsa_error()
        return RSA_pub(rsa, 1)

    def new_pub_key(e_n):
        # type: (Tuple[bytes, bytes]) -> RSA_pub
        """
        Instantiate an RSA_pub object from an (e, n) tuple.

        :param e: The RSA public exponent; it is a string in OpenSSL's MPINT
                  format - 4-byte big-endian bit-count followed by the
                  appropriate number of bits.

        :param n: The RSA composite of primes; it is a string in OpenSSL's
                  MPINT format - 4-byte big-endian bit-count followed by the
                  appropriate number of bits.

        :return: M2Crypto.RSA.RSA_pub object.
        """
        (e, n) = e_n
        rsa = m2.rsa_new()
        m2.rsa_set_en(rsa, e, n)
        return RSA_pub(rsa, 1)