1 files changed, 16 insertions, 35 deletions
diff --git a/src/cryptography/hazmat/primitives/asymmetric/utils.py b/src/cryptography/hazmat/primitives/asymmetric/utils.py
index ef1e7eb92..5f9b67786 100644
--- a/src/cryptography/hazmat/primitives/asymmetric/utils.py
+++ b/src/cryptography/hazmat/primitives/asymmetric/utils.py
@@ -4,49 +4,30 @@
 
 from __future__ import absolute_import, division, print_function
 
-import warnings
-
-from asn1crypto.algos import DSASignature
-
-import six
-
 from cryptography import utils
+from cryptography.hazmat._der import (
+    DERReader,
+    INTEGER,
+    SEQUENCE,
+    encode_der,
+    encode_der_integer,
+)
 from cryptography.hazmat.primitives import hashes
 
 
-def decode_rfc6979_signature(signature):
-    warnings.warn(
-        "decode_rfc6979_signature is deprecated and will "
-        "be removed in a future version, use decode_dss_signature instead.",
-        utils.PersistentlyDeprecated,
-        stacklevel=2
-    )
-    return decode_dss_signature(signature)
-
-
 def decode_dss_signature(signature):
-    data = DSASignature.load(signature, strict=True).native
-    return data['r'], data['s']
-
-
-def encode_rfc6979_signature(r, s):
-    warnings.warn(
-        "encode_rfc6979_signature is deprecated and will "
-        "be removed in a future version, use encode_dss_signature instead.",
-        utils.PersistentlyDeprecated,
-        stacklevel=2
-    )
-    return encode_dss_signature(r, s)
+    with DERReader(signature).read_single_element(SEQUENCE) as seq:
+        r = seq.read_element(INTEGER).as_integer()
+        s = seq.read_element(INTEGER).as_integer()
+        return r, s
 
 
 def encode_dss_signature(r, s):
-    if (
-        not isinstance(r, six.integer_types) or
-        not isinstance(s, six.integer_types)
-    ):
-        raise ValueError("Both r and s must be integers")
-
-    return DSASignature({'r': r, 's': s}).dump()
+    return encode_der(
+        SEQUENCE,
+        encode_der(INTEGER, encode_der_integer(r)),
+        encode_der(INTEGER, encode_der_integer(s)),
+    )
 
 
 class Prehashed(object):