editing README

Author: hansonchar

README.md

@@ -97,7 +97,7 @@ There is a variety of existing [EncryptionMaterialsProvider][materialprovider] i
 
 ## Supported Algorithms
 
-For content encryption, the encryption algorithm is determined by the user specified [SecretKey][secretkey], as long as it can be used with the encryption mode "CBC" with "PKCS5Padding".  Typically, this means "AES".
+For content encryption, the encryption algorithm is determined by the user specified [SecretKey][secretkey], as long as it is a block cipher that can be used with the encryption mode "CBC" and "PKCS5Padding".  Typically, this means "AES".
 
 For signing, the user specified signing key can be either symmetric or asymmetric.  For asymmetric signing (where the user would provide a signing key in the form of a [PrivateKey][privatekey]), currently the only supported algorithm is "SHA256withRSA".  For symmetric signing (where the user would provide the signing key in the form of a [SecretyKey][secretkey]), the algorithm would be determined by the provided key.  A typical algorithm for a symmetric signing key is "HmacSHA256".