1 files changed, 45 insertions, 5 deletions

diff --git a/oauthlib/oauth1/rfc5849/__init__.py b/oauthlib/oauth1/rfc5849/__init__.py
index f7cd3f3..c559251 100644
--- a/oauthlib/oauth1/rfc5849/__init__.py
+++ b/oauthlib/oauth1/rfc5849/__init__.py
@@ -4,6 +4,19 @@ oauthlib.oauth1.rfc5849
 
 This module is an implementation of various logic needed
 for signing and checking OAuth 1.0 RFC 5849 requests.
+
+It supports all three standard signature methods defined in RFC 5849:
+
+- HMAC-SHA1
+- RSA-SHA1
+- PLAINTEXT
+
+It also supports signature methods that are not defined in RFC 5849. These are
+based on the standard ones but replace SHA-1 with the more secure SHA-256:
+
+- HMAC-SHA256
+- RSA-SHA256
+
 """
 import base64
 import hashlib
@@ -18,14 +31,38 @@ from . import parameters, signature
 
 log = logging.getLogger(__name__)
 
-
+# Available signature methods
+#
+# Note: SIGNATURE_HMAC and SIGNATURE_RSA are kept for backward compatibility
+# with previous versions of this library, when it the only HMAC-based and
+# RSA-based signature methods were HMAC-SHA1 and RSA-SHA1. But now that it
+# supports other hashing algorithms besides SHA1, explicitly identifying which
+# hashing algorithm is being used is recommended.
+#
+# Note: if additional values are defined here, don't forget to update the
+# imports in "../__init__.py" so they are available outside this module.
 
 SIGNATURE_HMAC_SHA1 = "HMAC-SHA1"
 SIGNATURE_HMAC_SHA256 = "HMAC-SHA256"
-SIGNATURE_HMAC = SIGNATURE_HMAC_SHA1
-SIGNATURE_RSA = "RSA-SHA1"
+SIGNATURE_HMAC_SHA512 = "HMAC-SHA512"
+SIGNATURE_HMAC = SIGNATURE_HMAC_SHA1  # deprecated variable for HMAC-SHA1
+
+SIGNATURE_RSA_SHA1 = "RSA-SHA1"
+SIGNATURE_RSA_SHA256 = "RSA-SHA256"
+SIGNATURE_RSA_SHA512 = "RSA-SHA512"
+SIGNATURE_RSA = SIGNATURE_RSA_SHA1  # deprecated variable for RSA-SHA1
+
 SIGNATURE_PLAINTEXT = "PLAINTEXT"
-SIGNATURE_METHODS = (SIGNATURE_HMAC_SHA1, SIGNATURE_HMAC_SHA256, SIGNATURE_RSA, SIGNATURE_PLAINTEXT)
+
+SIGNATURE_METHODS = (
+    SIGNATURE_HMAC_SHA1,
+    SIGNATURE_HMAC_SHA256,
+    SIGNATURE_HMAC_SHA512,
+    SIGNATURE_RSA_SHA1,
+    SIGNATURE_RSA_SHA256,
+    SIGNATURE_RSA_SHA512,
+    SIGNATURE_PLAINTEXT
+)
 
 SIGNATURE_TYPE_AUTH_HEADER = 'AUTH_HEADER'
 SIGNATURE_TYPE_QUERY = 'QUERY'
@@ -40,7 +77,10 @@ class Client:
     SIGNATURE_METHODS = {
         SIGNATURE_HMAC_SHA1: signature.sign_hmac_sha1_with_client,
         SIGNATURE_HMAC_SHA256: signature.sign_hmac_sha256_with_client,
-        SIGNATURE_RSA: signature.sign_rsa_sha1_with_client,
+        SIGNATURE_HMAC_SHA512: signature.sign_hmac_sha512_with_client,
+        SIGNATURE_RSA_SHA1: signature.sign_rsa_sha1_with_client,
+        SIGNATURE_RSA_SHA256: signature.sign_rsa_sha256_with_client,
+        SIGNATURE_RSA_SHA512: signature.sign_rsa_sha512_with_client,
         SIGNATURE_PLAINTEXT: signature.sign_plaintext_with_client
     }