def _build_ekey_from_string(key):
bio = _string_to_bio(key)
ekey = evp.PEM_read_bio_PUBKEY(bio, None, None, None)
if not ekey:
raise EnvelopeError("Could not create encryption key from string")
evp.BIO_free(bio)
return ekey
def _build_dkey_from_string(key):
bio = _string_to_bio(key)
dkey = evp.PEM_read_bio_PrivateKey(bio, None, None, None)
if not dkey:
raise EnvelopeError("Could not build decryption key from string")
evp.BIO_free(bio)
return dkey
def _build_skey_from_string(key):
buf = ctypes.create_string_buffer(key)
bio = evp.BIO_new_mem_buf(buf, len(buf.value))
skey = evp.PEM_read_bio_PrivateKey(bio, None, None, None, None)
if not skey:
raise SignatureError(
"Could not construct signing key from the given string")
evp.BIO_free(bio)
return skey
def keygen(bitlength=1024, e=65537, pem=True):
key = evp.RSA_generate_key(bitlength, e, None, None)
if not key:
raise EnvelopeError("Could not generate key")
if pem:
private_bio = evp.BIO_new(evp.BIO_s_mem())
if not private_bio:
raise KeygenError("Could not create temporary storage")
public_bio = evp.BIO_new(evp.BIO_s_mem())
if not public_bio:
raise KeygenError("Could not create temporary storage")
private_buf = ctypes.create_string_buffer('', 65537)
if not private_buf:
raise MemoryError("Could not allocate key storage")
public_buf = ctypes.create_string_buffer('', 65537)
if not public_buf:
raise MemoryError("Could not allocate key storage")
if not evp.PEM_write_bio_RSAPrivateKey(private_bio, key, None, None, 0,
0, None):
raise KeygenError("Could not write private key")
if not evp.PEM_write_bio_RSA_PUBKEY(public_bio, key):
raise KeygenError("Could not write public key")
public_len = evp.BIO_read(public_bio, public_buf, 65537)
private_len = evp.BIO_read(private_bio, private_buf, 65537)
evp.BIO_free(public_bio)
evp.BIO_free(private_bio)
return public_buf.value, private_buf.value
else:
# we go through this rigamarole because if there's an engine
# in place it won't populate the RSA key's values properly.
key_bio = evp.BIO_new(evp.BIO_s_mem())
if not key_bio:
raise KeygenError("Could not create temporary storage")
if not evp.RSA_print(key_bio, key, 0):
raise KeygenError("Could not stringify key")
key_buf = ctypes.create_string_buffer('', 65537)
if not key_buf:
raise MemoryError("Could not allocate key storage")
evp.BIO_read(key_bio, key_buf, 65537)
evp.BIO_free(key_bio)
key_string = key_buf.value
return key, _parse_printed_key(key_string)