def encrypt(message, pub_key):
"""Encrypts the given message using PKCS#1 v1.5
:param message: the message to encrypt. Must be a byte string no longer than
``k-11`` bytes, where ``k`` is the number of bytes needed to encode
the ``n`` component of the public key.
:param pub_key: the :py:class:`rsa.PublicKey` to encrypt with.
:raise OverflowError: when the message is too large to fit in the padded
block.
>>> from rsa import key, common
>>> (pub_key, priv_key) = key.newkeys(256)
>>> message = b'hello'
>>> crypto = encrypt(message, pub_key)
The crypto text should be just as long as the public key 'n' component:
>>> len(crypto) == common.byte_size(pub_key.n)
True
"""
keylength = common.byte_size(pub_key.n)
padded = _pad_for_encryption(message, keylength)
payload = transform.bytes2int(padded)
encrypted = core.encrypt_int(payload, pub_key.e, pub_key.n)
block = transform.int2bytes(encrypted, keylength)
return block
def verify(message, signature, pub_key):
"""Verifies that the signature matches the message.
The hash method is detected automatically from the signature.
:param message: the signed message. Can be an 8-bit string or a file-like
object. If ``message`` has a ``read()`` method, it is assumed to be a
file-like object.
:param signature: the signature block, as created with :py:func:`rsa.sign`.
:param pub_key: the :py:class:`rsa.PublicKey` of the person signing the message.
:raise VerificationError: when the signature doesn't match the message.
"""
keylength = common.byte_size(pub_key.n)
encrypted = transform.bytes2int(signature)
decrypted = core.decrypt_int(encrypted, pub_key.e, pub_key.n)
clearsig = transform.int2bytes(decrypted, keylength)
# Get the hash method
method_name = _find_method_hash(clearsig)
message_hash = _hash(message, method_name)
# Reconstruct the expected padded hash
cleartext = HASH_ASN1[method_name] + message_hash
expected = _pad_for_signing(cleartext, keylength)
# Compare with the signed one
if expected != clearsig:
raise VerificationError('Verification failed')
return True
def decodifica_linha(g, linhas):
decod = []
print "Revertendo o int para string..."
for linha in range(0, linhas):
decod.append(transform.int2bytes(g[linha]))
print"linha", linha + 1, decod[linha]
print"Decodificacao concluida"
print"************************************************"
return decod
def mgf1(seed, length, hasher='SHA-1'):
"""
MGF1 is a Mask Generation Function based on a hash function.
A mask generation function takes an octet string of variable length and a
desired output length as input, and outputs an octet string of the desired
length. The plaintext-awareness of RSAES-OAEP relies on the random nature of
the output of the mask generation function, which in turn relies on the
random nature of the underlying hash.
:param bytes seed: seed from which mask is generated, an octet string
:param int length: intended length in octets of the mask, at most 2^32(hLen)
:param str hasher: hash function (hLen denotes the length in octets of the hash
function output)
:return: mask, an octet string of length `length`
:rtype: bytes
:raise OverflowError: when `length` is too large for the specified `hasher`
:raise ValueError: when specified `hasher` is invalid
"""
try:
hash_length = pkcs1.HASH_METHODS[hasher]().digest_size
except KeyError:
raise ValueError(
'Invalid `hasher` specified. Please select one of: {hash_list}'.
format(hash_list=', '.join(sorted(pkcs1.HASH_METHODS.keys()))))
# If l > 2^32(hLen), output "mask too long" and stop.
if length > (2**32 * hash_length):
raise OverflowError(
"Desired length should be at most 2**32 times the hasher's output "
"length ({hash_length} for {hasher} function)".format(
hash_length=hash_length,
hasher=hasher,
))
# Looping `counter` from 0 to ceil(l / hLen)-1, build `output` based on the
# hashes formed by (`seed` + C), being `C` an octet string of length 4
# generated by converting `counter` with the primitive I2OSP
output = b''.join(
pkcs1.compute_hash(
seed + transform.int2bytes(counter, fill_size=4),
method_name=hasher,
) for counter in range(common.ceil_div(length, hash_length) + 1))
# Output the leading `length` octets of `output` as the octet string mask.
return output[:length]
def verify(message, signature, pub_key):
'''Verifies that the signature matches the message.
The hash method is detected automatically from the signature.
:param message: the signed message. Can be an 8-bit string or a file-like
object. If ``message`` has a ``read()`` method, it is assumed to be a
file-like object.
:param signature: the signature block, as created with :py:func:`rsa.sign`.
:param pub_key: the :py:class:`rsa.PublicKey` of the person signing the message.
:raise VerificationError: when the signature doesn't match the message.
.. warning::
Never display the stack trace of a
:py:class:`rsa.pkcs1.VerificationError` exception. It shows where in
the code the exception occurred, and thus leaks information about the
key. It's only a tiny bit of information, but every bit makes cracking
the keys easier.
'''
blocksize = common.byte_size(pub_key.n)
encrypted = transform.bytes2int(signature)
decrypted = core.decrypt_int(encrypted, pub_key.e, pub_key.n)
clearsig = transform.int2bytes(decrypted, blocksize)
# If we can't find the signature marker, verification failed.
if clearsig[0:2] != b('\x00\x01'):
raise VerificationError('Verification failed')
# Find the 00 separator between the padding and the payload
try:
sep_idx = clearsig.index(b('\x00'), 2)
except ValueError:
raise VerificationError('Verification failed')
# Get the hash and the hash method
(method_name, signature_hash) = _find_method_hash(clearsig[sep_idx+1:])
message_hash = _hash(message, method_name)
# Compare the real hash to the hash in the signature
if message_hash != signature_hash:
raise VerificationError('Verification failed')
return True
def sign(message, priv_key, hash):
"""Signs the message with the private key.
Hashes the message, then signs the hash with the given key. This is known
as a "detached signature", because the message itself isn't altered.
:param message: the message to sign. Can be an 8-bit string or a file-like
object. If ``message`` has a ``read()`` method, it is assumed to be a
file-like object.
:param priv_key: the :py:class:`rsa.PrivateKey` to sign with
:param hash: the hash method used on the message. Use 'MD5', 'SHA-1',
'SHA-256', 'SHA-384' or 'SHA-512'.
:return: a message signature block.
:raise OverflowError: if the private key is too small to contain the
requested hash.
"""
# Get the ASN1 code for this hash method
if hash not in HASH_ASN1:
raise ValueError('Invalid hash method: %s' % hash)
asn1code = HASH_ASN1[hash]
# Calculate the hash
hash = _hash(message, hash)
# Encrypt the hash with the private key
cleartext = asn1code + hash
keylength = common.byte_size(priv_key.n)
padded = _pad_for_signing(cleartext, keylength)
payload = transform.bytes2int(padded)
encrypted = priv_key.blinded_encrypt(payload)
block = transform.int2bytes(encrypted, keylength)
return block
def decrypt(crypto, priv_key):
r"""Decrypts the given message using PKCS#1 v1.5
The decryption is considered 'failed' when the resulting cleartext doesn't
start with the bytes 00 02, or when the 00 byte between the padding and
the message cannot be found.
:param crypto: the crypto text as returned by :py:func:`rsa.encrypt`
:param priv_key: the :py:class:`rsa.PrivateKey` to decrypt with.
:raise DecryptionError: when the decryption fails. No details are given as
to why the code thinks the decryption fails, as this would leak
information about the private key.
>>> import rsa
>>> (pub_key, priv_key) = rsa.newkeys(256)
It works with strings:
>>> crypto = encrypt(b'hello', pub_key)
>>> decrypt(crypto, priv_key)
b'hello'
And with binary data:
>>> crypto = encrypt(b'\x00\x00\x00\x00\x01', pub_key)
>>> decrypt(crypto, priv_key)
b'\x00\x00\x00\x00\x01'
Altering the encrypted information will *likely* cause a
:py:class:`rsa.pkcs1.DecryptionError`. If you want to be *sure*, use
:py:func:`rsa.sign`.
.. warning::
Never display the stack trace of a
:py:class:`rsa.pkcs1.DecryptionError` exception. It shows where in the
code the exception occurred, and thus leaks information about the key.
It's only a tiny bit of information, but every bit makes cracking the
keys easier.
>>> crypto = encrypt(b'hello', pub_key)
>>> crypto = crypto[0:5] + b'X' + crypto[6:] # change a byte
>>> decrypt(crypto, priv_key)
Traceback (most recent call last):
...
rsa.pkcs1.DecryptionError: Decryption failed
"""
blocksize = common.byte_size(priv_key.n)
encrypted = transform.bytes2int(crypto)
decrypted = priv_key.blinded_decrypt(encrypted)
cleartext = transform.int2bytes(decrypted, blocksize)
# If we can't find the cleartext marker, decryption failed.
if cleartext[0:2] != b('\x00\x02'):
raise DecryptionError('Decryption failed')
# Find the 00 separator between the padding and the message
try:
sep_idx = cleartext.index(b('\x00'), 2)
except ValueError:
raise DecryptionError('Decryption failed')
return cleartext[sep_idx + 1:]
for linha in range(0, linhas):
# a funcao pow(x,y,z) eh nativa do python e com 3 argumentos vale (x**y) % z ou seja, x^y modz
c.append(pow(linha_int[linha], e, n))
print"C=M^e mod(n) vale:", linha + 1, c[linha]
print"Decryptando..."
for linha in range(0, linhas):
g.append(pow(c[linha], d, n))
print"M=C^d mod(n) vale:", linha, g[linha]
print "Revertendo o int para string..."
for linha in range(0, linhas):
decod.append(transform.int2bytes(g[linha]))
print"linha", linha, decod[linha]
print"Codificacao concluida"
print"************************************************"
exit(0)
print"Algoritmo de forca bruta..."
# Conhecida a mensagem M e a chave publica e, achar a chave privada d, sabendo que n=pq e (
#https://www.vivaolinux.com.br/artigo/Quebrando-a-criptografia-RSA?pagina=3
duracao = verifica_fatores(n)
print duracao
for linha in range(0, linhas):
# a funcao pow(x,y,z) eh nativa do python e com 3 argumentos vale (x**y) % z ou seja, x^y modz
c.append(pow(linha_int[linha], e, n))
print "C=M^e mod(n) vale:", linha + 1, c[linha]
print "Decryptando..."
for linha in range(0, linhas):
g.append(pow(c[linha], d, n))
print "M=C^d mod(n) vale:", linha, g[linha]
print "Revertendo o int para string..."
for linha in range(0, linhas):
decod.append(transform.int2bytes(g[linha]))
print "linha", linha, decod[linha]
print "Codificacao concluida"
print "************************************************"
exit(0)
print "Algoritmo de forca bruta..."
# Conhecida a mensagem M e a chave publica e, achar a chave privada d, sabendo que n=pq e (
#https://www.vivaolinux.com.br/artigo/Quebrando-a-criptografia-RSA?pagina=3
duracao = verifica_fatores(n)
print duracao