def get_public_key_breakdown(cls, key):
"""Returns the breakdown of the given public key.
:param str key: PEM encoded RSA public key.
:return: Tuple of binary key, modulus and exponent.
:rtype: (str, str, str)
"""
# Strip the text part
if not (key.startswith(cls.PUB_KEY_BEGIN)
and key.endswith(cls.PUB_KEY_END)):
raise RuntimeError('Given key is not Public key')
key = key[len(cls.PUB_KEY_BEGIN):-len(cls.PUB_KEY_END)]
# Convert to der format
key_bin = base64.b64decode(key)
key = nice_binary_to_string(key_bin, sep=' ',
length=len(key_bin)).split(' ')
# Parse the key
key_objs = asn1.parse(key)
# Get the modulus & exponent
modulus = ' '.join(key_objs[0].value[2].value[0].value)
exponent = ' '.join(key_objs[0].value[2].value[1].value)
# return the keys in binary
return (key_bin, nice_string_to_binary(modulus, sep=' '),
nice_string_to_binary(exponent, sep=' '))
def get_public_key_from_breakdown(cls, modulus, exponent):
"""Returns the public key created using the modulus and exponent.
:param str modulus: Modulus string.
:param str exponent: Exponent string.
:return: PEM encoded RSA public key.
:rtype: str
"""
def con_bin_2_list(v):
return nice_binary_to_string(v, sep=':', length=len(v)).split(':')
# Convert to lists
modulus = con_bin_2_list(modulus)
exponent = con_bin_2_list(exponent)
for i, val in enumerate(exponent):
if int(val, 16) != 0:
exponent = exponent[i:]
break
# Create the modulus, exponent objects
modulus_obj, exponent_obj = asn1.AsnObject(), asn1.AsnObject()
modulus_obj.set_data(modulus_obj.TYPE_INT, modulus)
exponent_obj.set_data(exponent_obj.TYPE_INT, exponent)
# Create the higher level objects
tmp2 = asn1.AsnObject()
tmp2.set_data(modulus_obj.TYPE_SEQ, [modulus_obj, exponent_obj])
tmp1 = asn1.AsnObject()
tmp1.set_data(modulus_obj.TYPE_BIT,
nice_string_to_list(tmp2.pack()),
use_eoc=True)
tmp01 = asn1.AsnObject()
tmp01.set_data(modulus_obj.TYPE_NULL, [])
tmp00 = asn1.AsnObject()
tmp00.set_data(modulus_obj.TYPE_OID,
['2a', '86', '48', '86', 'f7', '0d', '01', '01', '01'])
tmp0 = asn1.AsnObject()
tmp0.set_data(modulus_obj.TYPE_SEQ, [tmp00, tmp01])
tmp = asn1.AsnObject()
tmp.set_data(modulus_obj.TYPE_SEQ, [tmp0, tmp1, tmp2])
# Create the key
key_list = nice_string_to_list(tmp.pack())
key_bin = nice_string_to_binary(':'.join(key_list), sep=':')
return (cls.PUB_KEY_BEGIN +
nice_string_to_multiline(base64.b64encode(key_bin), 64) +
cls.PUB_KEY_END)