Python Crypto.Hash.SHA.new() Examples

def _parse_kexdh_reply(self, m):
        # client mode
        host_key = m.get_string()
        self.f = m.get_mpint()
        if (self.f < 1) or (self.f > P - 1):
            raise SSHException('Server kex "f" is out of range')
        sig = m.get_string()
        K = pow(self.f, self.x, P)
        # okay, build up the hash H of (V_C || V_S || I_C || I_S || K_S || e || f || K)
        hm = Message()
        hm.add(self.transport.local_version, self.transport.remote_version,
               self.transport.local_kex_init, self.transport.remote_kex_init)
        hm.add_string(host_key)
        hm.add_mpint(self.e)
        hm.add_mpint(self.f)
        hm.add_mpint(K)
        self.transport._set_K_H(K, SHA.new(str(hm)).digest())
        self.transport._verify_key(host_key, sig)
        self.transport._activate_outbound() 

def generateQ(randfunc):
    S=randfunc(20)
    hash1=SHA.new(S).digest()
    hash2=SHA.new(long_to_bytes(bytes_to_long(S)+1)).digest()
    q = bignum(0)
    for i in range(0,20):
        c=bord(hash1[i])^bord(hash2[i])
        if i==0:
            c=c | 128
        if i==19:
            c= c | 1
        q=q*256+c
    while (not isPrime(q)):
        q=q+2
    if pow(2,159L) < q < pow(2,160L):
        return S, q
    raise RuntimeError('Bad q value generated') 

def get_bytes (self, N):
        """get_bytes(N:int) : string
        Return N bytes of random data.
        """

        s=''
        i, pool = self._getPos, self._randpool
        h=self._hash.new()
        dsize = self._hash.digest_size
        num = N
        while num > 0:
            h.update( self._randpool[i:i+dsize] )
            s = s + h.digest()
            num = num - dsize
            i = (i + dsize) % self.bytes
            if i<dsize:
                self.stir()
                i=self._getPos

        self._getPos = i
        self._updateEntropyEstimate(- 8*N)
        return s[:N] 

def signMsg(text, imported_key):

    seq2 = asn1.DerSequence()
    data = '\n'.join(imported_key.strip().split('\n')[1:-1]).decode('base64')
    seq2.decode(data)
    p, q, g, y, x = seq2[1:]

    key2 = DSA.construct((y, g, p, q, x))
    
    k1 = random.StrongRandom().randint(1,key2.q-1)

    h = SHA.new(text).digest()

    sig = key2.sign(h, k1)
    
    return sig 

def generateQ(randfunc):
    S=randfunc(20)
    hash1=SHA.new(S).digest()
    hash2=SHA.new(long_to_bytes(bytes_to_long(S)+1)).digest()
    q = bignum(0)
    for i in range(0,20):
        c=ord(hash1[i])^ord(hash2[i])
        if i==0:
            c=c | 128
        if i==19:
            c= c | 1
        q=q*256+c
    while (not isPrime(q)):
        q=q+2
    if pow(2,159) < q < pow(2,160):
        return S, q
    raise error('Bad q value generated') 

def generateQ(randfunc):
    S=randfunc(20)
    hash1=SHA.new(S).digest()
    hash2=SHA.new(long_to_bytes(bytes_to_long(S)+1)).digest()
    q = bignum(0)
    for i in range(0,20):
        c=ord(hash1[i])^ord(hash2[i])
        if i==0:
            c=c | 128
        if i==19:
            c= c | 1
        q=q*256+c
    while (not isPrime(q)):
        q=q+2
    if pow(2,159L) < q < pow(2,160L):
        return S, q
    raise error, 'Bad q value generated' 

def stir (self, s = ''):
        """stir(s:string)
        Mix up the randomness pool.  This will call add_event() twice,
        but out of paranoia the entropy attribute will not be
        increased.  The optional 's' parameter is a string that will
        be hashed with the randomness pool.
        """

        entropy=self.entropy            # Save inital entropy value
        self.add_event()

        # Loop over the randomness pool: hash its contents
        # along with a counter, and add the resulting digest
        # back into the pool.
        for i in range(self.bytes / self._hash.digest_size):
            h = self._hash.new(self._randpool)
            h.update(str(self.__counter) + str(i) + str(self._addPos) + s)
            self._addBytes( h.digest() )
            self.__counter = (self.__counter + 1) & 0xFFFFffff

        self._addPos, self._getPos = 0, self._hash.digest_size
        self.add_event()

        # Restore the old value of the entropy.
        self.entropy=entropy 

def stir (self, s = ''):
        """stir(s:string)
        Mix up the randomness pool.  This will call add_event() twice,
        but out of paranoia the entropy attribute will not be
        increased.  The optional 's' parameter is a string that will
        be hashed with the randomness pool.
        """

        entropy=self.entropy            # Save inital entropy value
        self.add_event()

        # Loop over the randomness pool: hash its contents
        # along with a counter, and add the resulting digest
        # back into the pool.
        for i in range(self.bytes / self._hash.digest_size):
            h = self._hash.new(self._randpool)
            h.update(str(self.__counter) + str(i) + str(self._addPos) + s)
            self._addBytes( h.digest() )
            self.__counter = (self.__counter + 1) & 0xFFFFffffL

        self._addPos, self._getPos = 0, self._hash.digest_size
        self.add_event()

        # Restore the old value of the entropy.
        self.entropy=entropy 

def get_bytes (self, N):
        """get_bytes(N:int) : string
        Return N bytes of random data.
        """

        s=''
        i, pool = self._getPos, self._randpool
        h=self._hash.new()
        dsize = self._hash.digest_size
        num = N
        while num > 0:
            h.update( self._randpool[i:i+dsize] )
            s = s + h.digest()
            num = num - dsize
            i = (i + dsize) % self.bytes
            if i<dsize:
                self.stir()
                i=self._getPos

        self._getPos = i
        self._updateEntropyEstimate(- 8*N)
        return s[:N] 

def verifyMsg(text, imported_key, sig):

    seq2 = asn1.DerSequence()
    data = '\n'.join(imported_key.strip().split('\n')[1:-1]).decode('base64')
    seq2.decode(data)
    p, q, g, y, x = seq2[1:]

    key2 = DSA.construct((y, g, p, q, x))
    
    k1 = random.StrongRandom().randint(1,key2.q-1)

    h = SHA.new(text).digest()

    a = key2.verify(h, sig)
    
    return a 

def _parse_kexdh_gex_reply(self, m):
        host_key = m.get_string()
        self.f = m.get_mpint()
        sig = m.get_string()
        if (self.f < 1) or (self.f > self.p - 1):
            raise SSHException('Server kex "f" is out of range')
        K = pow(self.f, self.x, self.p)
        # okay, build up the hash H of (V_C || V_S || I_C || I_S || K_S || min || n || max || p || g || e || f || K)
        hm = Message()
        hm.add(self.transport.local_version, self.transport.remote_version,
               self.transport.local_kex_init, self.transport.remote_kex_init,
               host_key)
        if not self.old_style:
            hm.add_int(self.min_bits)
        hm.add_int(self.preferred_bits)
        if not self.old_style:
            hm.add_int(self.max_bits)
        hm.add_mpint(self.p)
        hm.add_mpint(self.g)
        hm.add_mpint(self.e)
        hm.add_mpint(self.f)
        hm.add_mpint(K)
        self.transport._set_K_H(K, SHA.new(str(hm)).digest())
        self.transport._verify_key(host_key, sig)
        self.transport._activate_outbound() 

def generate(bits, progress_func=None):
        """
        Generate a new private RSA key.  This factory function can be used to
        generate a new host key or authentication key.

        @param bits: number of bits the generated key should be.
        @type bits: int
        @param progress_func: an optional function to call at key points in
            key generation (used by C{pyCrypto.PublicKey}).
        @type progress_func: function
        @return: new private key
        @rtype: L{RSAKey}
        """
        rsa = RSA.generate(bits, rng.read, progress_func)
        key = RSAKey(vals=(rsa.e, rsa.n))
        key.d = rsa.d
        key.p = rsa.p
        key.q = rsa.q
        return key 

def _parse_kexdh_reply(self, m):
        # client mode
        host_key = m.get_string()
        self.f = m.get_mpint()
        if (self.f < 1) or (self.f > P - 1):
            raise SSHException('Server kex "f" is out of range')
        sig = m.get_string()
        K = pow(self.f, self.x, P)
        # okay, build up the hash H of (V_C || V_S || I_C || I_S || K_S || e || f || K)
        hm = Message()
        hm.add(self.transport.local_version, self.transport.remote_version,
               self.transport.local_kex_init, self.transport.remote_kex_init)
        hm.add_string(host_key)
        hm.add_mpint(self.e)
        hm.add_mpint(self.f)
        hm.add_mpint(K)
        self.transport._set_K_H(K, SHA.new(str(hm)).digest())
        self.transport._verify_key(host_key, sig)
        self.transport._activate_outbound() 

def generate(bits=1024, progress_func=None):
        """
        Generate a new private DSS key.  This factory function can be used to
        generate a new host key or authentication key.

        @param bits: number of bits the generated key should be.
        @type bits: int
        @param progress_func: an optional function to call at key points in
            key generation (used by C{pyCrypto.PublicKey}).
        @type progress_func: function
        @return: new private key
        @rtype: L{DSSKey}
        """
        dsa = DSA.generate(bits, rng.read, progress_func)
        key = DSSKey(vals=(dsa.p, dsa.q, dsa.g, dsa.y))
        key.x = dsa.x
        return key 

def verify_ssh_sig(self, data, msg):
        if len(str(msg)) == 40:
            # spies.com bug: signature has no header
            sig = str(msg)
        else:
            kind = msg.get_string()
            if kind != 'ssh-dss':
                return 0
            sig = msg.get_string()

        # pull out (r, s) which are NOT encoded as mpints
        sigR = util.inflate_long(sig[:20], 1)
        sigS = util.inflate_long(sig[20:], 1)
        sigM = util.inflate_long(SHA.new(data).digest(), 1)

        dss = DSA.construct((long(self.y), long(self.g), long(self.p), long(self.q)))
        return dss.verify(sigM, (sigR, sigS)) 

def _parse_newkeys(self, m):
        self._log(DEBUG, 'Switch to new keys ...')
        self._activate_inbound()
        # can also free a bunch of stuff here
        self.local_kex_init = self.remote_kex_init = None
        self.K = None
        self.kex_engine = None
        if self.server_mode and (self.auth_handler is None):
            # create auth handler for server mode
            self.auth_handler = AuthHandler(self)
        if not self.initial_kex_done:
            # this was the first key exchange
            self.initial_kex_done = True
        # send an event?
        if self.completion_event != None:
            self.completion_event.set()
        # it's now okay to send data again (if this was a re-key)
        if not self.packetizer.need_rekey():
            self.in_kex = False
        self.clear_to_send_lock.acquire()
        try:
            self.clear_to_send.set()
        finally:
            self.clear_to_send_lock.release()
        return 

def _get_cipher(self, name, key, iv):
        if name not in self._cipher_info:
            raise SSHException('Unknown client cipher ' + name)
        if name in ('arcfour128', 'arcfour256'):
            # arcfour cipher
            cipher = self._cipher_info[name]['class'].new(key)
            # as per RFC 4345, the first 1536 bytes of keystream
            # generated by the cipher MUST be discarded
            cipher.encrypt(" " * 1536)
            return cipher
        elif name.endswith("-ctr"):
            # CTR modes, we need a counter
            counter = Counter.new(nbits=self._cipher_info[name]['block-size'] * 8, initial_value=util.inflate_long(iv, True))
            return self._cipher_info[name]['class'].new(key, self._cipher_info[name]['mode'], iv, counter)
        else:
            return self._cipher_info[name]['class'].new(key, self._cipher_info[name]['mode'], iv) 

def _compute_key(self, id, nbytes):
        "id is 'A' - 'F' for the various keys used by ssh"
        m = Message()
        m.add_mpint(self.K)
        m.add_bytes(self.H)
        m.add_byte(id)
        m.add_bytes(self.session_id)
        out = sofar = SHA.new(str(m)).digest()
        while len(out) < nbytes:
            m = Message()
            m.add_mpint(self.K)
            m.add_bytes(self.H)
            m.add_bytes(sofar)
            digest = SHA.new(str(m)).digest()
            out += digest
            sofar += digest
        return out[:nbytes] 

def renegotiate_keys(self):
        """
        Force this session to switch to new keys.  Normally this is done
        automatically after the session hits a certain number of packets or
        bytes sent or received, but this method gives you the option of forcing
        new keys whenever you want.  Negotiating new keys causes a pause in
        traffic both ways as the two sides swap keys and do computations.  This
        method returns when the session has switched to new keys.

        @raise SSHException: if the key renegotiation failed (which causes the
            session to end)
        """
        self.completion_event = threading.Event()
        self._send_kex_init()
        while True:
            self.completion_event.wait(0.1)
            if not self.active:
                e = self.get_exception()
                if e is not None:
                    raise e
                raise SSHException('Negotiation failed.')
            if self.completion_event.isSet():
                break
        return 

def _compute_key(self, id, nbytes):
        "id is 'A' - 'F' for the various keys used by ssh"
        m = Message()
        m.add_mpint(self.K)
        m.add_bytes(self.H)
        m.add_byte(id)
        m.add_bytes(self.session_id)
        out = sofar = SHA.new(str(m)).digest()
        while len(out) < nbytes:
            m = Message()
            m.add_mpint(self.K)
            m.add_bytes(self.H)
            m.add_bytes(sofar)
            digest = SHA.new(str(m)).digest()
            out += digest
            sofar += digest
        return out[:nbytes] 

def _get_cipher(self, name, key, iv):
        if name not in self._cipher_info:
            raise SSHException('Unknown client cipher ' + name)
        if name in ('arcfour128', 'arcfour256'):
            # arcfour cipher
            cipher = self._cipher_info[name]['class'].new(key)
            # as per RFC 4345, the first 1536 bytes of keystream
            # generated by the cipher MUST be discarded
            cipher.encrypt(" " * 1536)
            return cipher
        elif name.endswith("-ctr"):
            # CTR modes, we need a counter
            counter = Counter.new(nbits=self._cipher_info[name]['block-size'] * 8, initial_value=util.inflate_long(iv, True))
            return self._cipher_info[name]['class'].new(key, self._cipher_info[name]['mode'], iv, counter)
        else:
            return self._cipher_info[name]['class'].new(key, self._cipher_info[name]['mode'], iv) 

def sign_ssh_data(self, rng, data):
        digest = SHA.new(data).digest()
        dss = DSA.construct((long(self.y), long(self.g), long(self.p), long(self.q), long(self.x)))
        # generate a suitable k
        qsize = len(util.deflate_long(self.q, 0))
        while True:
            k = util.inflate_long(rng.read(qsize), 1)
            if (k > 2) and (k < self.q):
                break
        r, s = dss.sign(util.inflate_long(digest, 1), k)
        m = Message()
        m.add_string('ssh-dss')
        # apparently, in rare cases, r or s may be shorter than 20 bytes!
        rstr = util.deflate_long(r, 0)
        sstr = util.deflate_long(s, 0)
        if len(rstr) < 20:
            rstr = '\x00' * (20 - len(rstr)) + rstr
        if len(sstr) < 20:
            sstr = '\x00' * (20 - len(sstr)) + sstr
        m.add_string(rstr + sstr)
        return m 

def verify_ssh_sig(self, data, msg):
        if len(str(msg)) == 40:
            # spies.com bug: signature has no header
            sig = str(msg)
        else:
            kind = msg.get_string()
            if kind != 'ssh-dss':
                return 0
            sig = msg.get_string()

        # pull out (r, s) which are NOT encoded as mpints
        sigR = util.inflate_long(sig[:20], 1)
        sigS = util.inflate_long(sig[20:], 1)
        sigM = util.inflate_long(SHA.new(data).digest(), 1)

        dss = DSA.construct((long(self.y), long(self.g), long(self.p), long(self.q)))
        return dss.verify(sigM, (sigR, sigS)) 

def generate(bits=1024, progress_func=None):
        """
        Generate a new private DSS key.  This factory function can be used to
        generate a new host key or authentication key.

        @param bits: number of bits the generated key should be.
        @type bits: int
        @param progress_func: an optional function to call at key points in
            key generation (used by C{pyCrypto.PublicKey}).
        @type progress_func: function
        @return: new private key
        @rtype: L{DSSKey}
        """
        dsa = DSA.generate(bits, rng.read, progress_func)
        key = DSSKey(vals=(dsa.p, dsa.q, dsa.g, dsa.y))
        key.x = dsa.x
        return key 

def _parse_kexdh_gex_reply(self, m):
        host_key = m.get_string()
        self.f = m.get_mpint()
        sig = m.get_string()
        if (self.f < 1) or (self.f > self.p - 1):
            raise SSHException('Server kex "f" is out of range')
        K = pow(self.f, self.x, self.p)
        # okay, build up the hash H of (V_C || V_S || I_C || I_S || K_S || min || n || max || p || g || e || f || K)
        hm = Message()
        hm.add(self.transport.local_version, self.transport.remote_version,
               self.transport.local_kex_init, self.transport.remote_kex_init,
               host_key)
        if not self.old_style:
            hm.add_int(self.min_bits)
        hm.add_int(self.preferred_bits)
        if not self.old_style:
            hm.add_int(self.max_bits)
        hm.add_mpint(self.p)
        hm.add_mpint(self.g)
        hm.add_mpint(self.e)
        hm.add_mpint(self.f)
        hm.add_mpint(K)
        self.transport._set_K_H(K, SHA.new(str(hm)).digest())
        self.transport._verify_key(host_key, sig)
        self.transport._activate_outbound() 

def generate(bits, progress_func=None):
        """
        Generate a new private RSA key.  This factory function can be used to
        generate a new host key or authentication key.

        @param bits: number of bits the generated key should be.
        @type bits: int
        @param progress_func: an optional function to call at key points in
            key generation (used by C{pyCrypto.PublicKey}).
        @type progress_func: function
        @return: new private key
        @rtype: L{RSAKey}
        """
        rsa = RSA.generate(bits, rng.read, progress_func)
        key = RSAKey(vals=(rsa.e, rsa.n))
        key.d = rsa.d
        key.p = rsa.p
        key.q = rsa.q
        return key 

def generateQ(randfunc):
    S=randfunc(20)
    hash1=SHA.new(S).digest()
    hash2=SHA.new(long_to_bytes(bytes_to_long(S)+1)).digest()
    q = bignum(0)
    for i in range(0,20):
        c=bord(hash1[i])^bord(hash2[i])
        if i==0:
            c=c | 128
        if i==19:
            c= c | 1
        q=q*256+c
    while (not isPrime(q)):
        q=q+2
    if pow(2,159L) < q < pow(2,160L):
        return S, q
    raise RuntimeError('Bad q value generated') 

def publickey(self):
        """Return a new key object containing only the public information."""
        return construct((self.p, self.q, self.g, self.y)) 

def open_session(self):
        """
        Request a new channel to the server, of type C{"session"}.  This
        is just an alias for C{open_channel('session')}.

        @return: a new L{Channel}
        @rtype: L{Channel}

        @raise SSHException: if the request is rejected or the session ends
            prematurely
        """
        return self.open_channel('session') 

def _measureTickSize(self):
        # _measureTickSize() tries to estimate a rough average of the
        # resolution of time that you can see from Python.  It does
        # this by measuring the time 100 times, computing the delay
        # between measurements, and taking the median of the resulting
        # list.  (We also hash all the times and add them to the pool)
        interval = [None] * 100
        h = self._hash.new(`(id(self),id(interval))`)

        # Compute 100 differences
        t=time.time()
        h.update(`t`)
        i = 0
        j = 0
        while i < 100:
            t2=time.time()
            h.update(`(i,j,t2)`)
            j += 1
            delta=int((t2-t)*1e6)
            if delta:
                interval[i] = delta
                i += 1
                t=t2

        # Take the median of the array of intervals
        interval.sort()
        self._ticksize=interval[len(interval)/2]
        h.update(`(interval,self._ticksize)`)
        # mix in the measurement times and wash the random pool
        self.stir(h.digest())