def sign(self, inputb):
"""
Sign the input with ECDSA method and returns the signature
"""
try:
size = len(inputb)
buff = OpenSSL.malloc(inputb, size)
digest = OpenSSL.malloc(0, 64)
md_ctx = OpenSSL.EVP_MD_CTX_create()
dgst_len = OpenSSL.pointer(OpenSSL.c_int(0))
siglen = OpenSSL.pointer(OpenSSL.c_int(0))
sig = OpenSSL.malloc(0, 151)
key = OpenSSL.EC_KEY_new_by_curve_name(self.curve)
if key == 0:
raise Exception("[OpenSSL] EC_KEY_new_by_curve_name FAIL ...")
priv_key = OpenSSL.BN_bin2bn(self.privkey, len(self.privkey), 0)
pub_key_x = OpenSSL.BN_bin2bn(self.pubkey_x, len(self.pubkey_x), 0)
pub_key_y = OpenSSL.BN_bin2bn(self.pubkey_y, len(self.pubkey_y), 0)
if (OpenSSL.EC_KEY_set_private_key(key, priv_key)) == 0:
raise Exception("[OpenSSL] EC_KEY_set_private_key FAIL ...")
group = OpenSSL.EC_KEY_get0_group(key)
pub_key = OpenSSL.EC_POINT_new(group)
if (OpenSSL.EC_POINT_set_affine_coordinates_GFp(group, pub_key,
pub_key_x,
pub_key_y,
0)) == 0:
raise Exception(
"[OpenSSL] EC_POINT_set_affine_coordinates_GFp FAIL ...")
if (OpenSSL.EC_KEY_set_public_key(key, pub_key)) == 0:
raise Exception("[OpenSSL] EC_KEY_set_public_key FAIL ...")
if (OpenSSL.EC_KEY_check_key(key)) == 0:
raise Exception("[OpenSSL] EC_KEY_check_key FAIL ...")
OpenSSL.EVP_MD_CTX_init(md_ctx)
OpenSSL.EVP_DigestInit(md_ctx, OpenSSL.EVP_ecdsa())
if (OpenSSL.EVP_DigestUpdate(md_ctx, buff, size)) == 0:
raise Exception("[OpenSSL] EVP_DigestUpdate FAIL ...")
OpenSSL.EVP_DigestFinal(md_ctx, digest, dgst_len)
OpenSSL.ECDSA_sign(0, digest, dgst_len.contents, sig, siglen, key)
if (OpenSSL.ECDSA_verify(0, digest, dgst_len.contents, sig,
siglen.contents, key)) != 1:
raise Exception("[OpenSSL] ECDSA_verify FAIL ...")
return sig.raw[:siglen.contents.value]
finally:
OpenSSL.EC_KEY_free(key)
OpenSSL.BN_free(pub_key_x)
OpenSSL.BN_free(pub_key_y)
OpenSSL.BN_free(priv_key)
OpenSSL.EC_POINT_free(pub_key)
OpenSSL.EVP_MD_CTX_destroy(md_ctx)
def verify(self, sig, inputb):
"""
Verify the signature with the input and the local public key.
Returns a boolean
"""
try:
bsig = OpenSSL.malloc(sig, len(sig))
binputb = OpenSSL.malloc(inputb, len(inputb))
digest = OpenSSL.malloc(0, 64)
dgst_len = OpenSSL.pointer(OpenSSL.c_int(0))
md_ctx = OpenSSL.EVP_MD_CTX_create()
key = OpenSSL.EC_KEY_new_by_curve_name(self.curve)
if key == 0:
raise Exception("[OpenSSL] EC_KEY_new_by_curve_name FAIL ...")
pub_key_x = OpenSSL.BN_bin2bn(self.pubkey_x, len(self.pubkey_x), 0)
pub_key_y = OpenSSL.BN_bin2bn(self.pubkey_y, len(self.pubkey_y), 0)
group = OpenSSL.EC_KEY_get0_group(key)
pub_key = OpenSSL.EC_POINT_new(group)
if (OpenSSL.EC_POINT_set_affine_coordinates_GFp(group, pub_key,
pub_key_x,
pub_key_y,
0)) == 0:
raise Exception(
"[OpenSSL] EC_POINT_set_affine_coordinates_GFp FAIL ...")
if (OpenSSL.EC_KEY_set_public_key(key, pub_key)) == 0:
raise Exception("[OpenSSL] EC_KEY_set_public_key FAIL ...")
if (OpenSSL.EC_KEY_check_key(key)) == 0:
raise Exception("[OpenSSL] EC_KEY_check_key FAIL ...")
OpenSSL.EVP_MD_CTX_init(md_ctx)
OpenSSL.EVP_DigestInit(md_ctx, OpenSSL.EVP_ecdsa())
if (OpenSSL.EVP_DigestUpdate(md_ctx, binputb, len(inputb))) == 0:
raise Exception("[OpenSSL] EVP_DigestUpdate FAIL ...")
OpenSSL.EVP_DigestFinal(md_ctx, digest, dgst_len)
ret = OpenSSL.ECDSA_verify(
0, digest, dgst_len.contents, bsig, len(sig), key)
if ret == -1:
return False # Fail to Check
else:
if ret == 0:
return False # Bad signature !
else:
return True # Good
return False
finally:
OpenSSL.EC_KEY_free(key)
OpenSSL.BN_free(pub_key_x)
OpenSSL.BN_free(pub_key_y)
OpenSSL.EC_POINT_free(pub_key)
OpenSSL.EVP_MD_CTX_destroy(md_ctx)