+"""
+This module provides interface for low-level private/public keypair operation
+
+PKey object of this module is wrapper around OpenSSL EVP_PKEY object.
+"""
+
+
from ctypes import c_char_p,c_void_p,byref,c_int,c_long, c_longlong, create_string_buffer,CFUNCTYPE,POINTER
from ctypescrypto import libcrypto
from ctypescrypto.exception import LibCryptoError,clear_err_stack
from ctypescrypto.bio import Membio
import sys
+
+__all__ = ['PKeyError','password_callback','PKey']
class PKeyError(LibCryptoError):
pass
CALLBACK_FUNC=CFUNCTYPE(c_int,c_char_p,c_int,c_int,c_char_p)
def password_callback(buf,length,rwflag,u):
+ """
+ Example password callback for private key. Assumes that
+ password is store in the userdata parameter, so allows to pass password
+ from constructor arguments to the libcrypto keyloading functions
+ """
cnt=len(u)
if length<cnt:
cnt=length
_cb=CALLBACK_FUNC(password_callback)
-class PKey:
+class PKey(object):
def __init__(self,ptr=None,privkey=None,pubkey=None,format="PEM",cansign=False,password=None):
if not ptr is None:
self.key=ptr
self.cansign=cansign
if not privkey is None or not pubkey is None:
- raise TypeError("Just one of pubkey or privkey can be specified")
+ raise TypeError("Just one of ptr, pubkey or privkey can be specified")
elif not privkey is None:
if not pubkey is None:
- raise TypeError("Just one of pubkey or privkey can be specified")
+ raise TypeError("Just one of ptr, pubkey or privkey can be specified")
b=Membio(privkey)
self.cansign=True
if format == "PEM":
rsa_keygen_bits=number - size of key to be generated
rsa_keygen_pubexp - RSA public expontent(default 65537)
- Algorithn specific parameters for DSA,DH and EC
+ Algorithm specific parameters for DSA,DH and EC
paramsfrom=PKey object
raise PKeyError("Error generating key")
libcrypto.EVP_PKEY_CTX_free(ctx)
return PKey(ptr=key,cansign=True)
+ def exportpub(self,format="PEM"):
+ """
+ Returns public key as PEM or DER structure.
+ """
+ b=Membio()
+ if format == "PEM":
+ r=libcrypto.PEM_write_bio_PUBKEY(b.bio,self.key)
+ else:
+ r=libcrypto.i2d_PUBKEY_bio(b.bio,self.key)
+ if r==0:
+ raise PKeyError("error serializing public key")
+ return str(b)
+ def exportpriv(self,format="PEM",password=None,cipher=None):
+ """
+ Returns private key as PEM or DER Structure.
+ If password and cipher are specified, encrypts key
+ on given password, using given algorithm. Cipher must be
+ an ctypescrypto.cipher.CipherType object
+ """
+ b=Membio()
+ if cipher is None:
+ evp_cipher=None
+ else:
+ if password is None:
+ raise NotImplementedError("Interactive password entry is not supported")
+ evp_cipher=cipher.cipher
+ if format == "PEM":
+ r=libcrypto.PEM_write_bio_PrivateKey(b.bio,self.key,evp_cipher,None,0,_cb,
+ password)
+ else:
+ if cipher is not None:
+ raise NotImplementedError("Der-formatted encrypted keys are not supported")
+ r=libcrypto.i2d_PrivateKey_bio(b.bio,self.key)
+ if r==0:
+ raise PKeyError("error serializing private key")
+ return str(b)
@staticmethod
def _configure_context(ctx,opts,skip=[]):
"""
continue
rv=libcrypto.EVP_PKEY_CTX_ctrl_str(ctx,oper,str(opts[oper]))
if rv==-2:
- raise PKeyError("Parameter %s is not supported by key"%(oper))
+ raise PKeyError("Parameter %s is not supported by key"%(oper,))
if rv<1:
- raise PKeyError("Error setting parameter %s"(oper))
+ raise PKeyError("Error setting parameter %s"%(oper,))
# Declare function prototypes
libcrypto.EVP_PKEY_cmp.argtypes=(c_void_p,c_void_p)
libcrypto.PEM_read_bio_PrivateKey.restype=c_void_p
libcrypto.EVP_PKEY_verify.argtypes=(c_void_p,c_char_p,c_long,c_char_p,c_long)
libcrypto.EVP_PKEY_verify_init.restype=c_int
libcrypto.EVP_PKEY_verify_init.argtypes=(c_void_p,)
-
+libcrypto.PEM_write_bio_PrivateKey.argtypes=(c_void_p,c_void_p,c_void_p,c_char_p,c_int,CALLBACK_FUNC,c_char_p)
+libcrypto.PEM_write_bio_PUBKEY.argtypes=(c_void_p,c_void_p)
+libcrypto.i2d_PUBKEY_bio.argtypes=(c_void_p,c_void_p)
+libcrypto.i2d_PrivateKey_bio.argtypes=(c_void_p,c_void_p)