diff --git a/source/JSONWebToken-Core.package/JWARSASHA256.class/README.md b/source/JSONWebToken-Core.package/JWARSASHA256.class/README.md
new file mode 100644
index 0000000..e69de29
diff --git a/source/JSONWebToken-Core.package/JWARSASHA256.class/class/parameterValue.st b/source/JSONWebToken-Core.package/JWARSASHA256.class/class/parameterValue.st
new file mode 100644
index 0000000..0642aed
--- /dev/null
+++ b/source/JSONWebToken-Core.package/JWARSASHA256.class/class/parameterValue.st
@@ -0,0 +1,3 @@
+accessing
+parameterValue
+	^ 'RS256'
\ No newline at end of file
diff --git a/source/JSONWebToken-Core.package/JWARSASHA256.class/class/signMessage.withKey..st b/source/JSONWebToken-Core.package/JWARSASHA256.class/class/signMessage.withKey..st
new file mode 100644
index 0000000..c48d300
--- /dev/null
+++ b/source/JSONWebToken-Core.package/JWARSASHA256.class/class/signMessage.withKey..st
@@ -0,0 +1,3 @@
+sign
+signMessage: aString withKey: anObject
+	self notYetImplemented 
\ No newline at end of file
diff --git a/source/JSONWebToken-Core.package/JWARSASHA256.class/properties.json b/source/JSONWebToken-Core.package/JWARSASHA256.class/properties.json
new file mode 100644
index 0000000..4bda1d9
--- /dev/null
+++ b/source/JSONWebToken-Core.package/JWARSASHA256.class/properties.json
@@ -0,0 +1,11 @@
+{
+	"commentStamp" : "",
+	"super" : "JsonWebAlgorithm",
+	"category" : "JSONWebToken-Core-JSONWebToken-Core",
+	"classinstvars" : [ ],
+	"pools" : [ ],
+	"classvars" : [ ],
+	"instvars" : [ ],
+	"name" : "JWARSASHA256",
+	"type" : "normal"
+}
\ No newline at end of file
diff --git a/source/JSONWebToken-Core.package/JWSCompactSerializer.class/instance/materialize..st b/source/JSONWebToken-Core.package/JWSCompactSerializer.class/instance/materialize..st
deleted file mode 100644
index 8f347b4..0000000
--- a/source/JSONWebToken-Core.package/JWSCompactSerializer.class/instance/materialize..st
+++ /dev/null
@@ -1,7 +0,0 @@
-reading
-materialize: aString 
-	| parts jws |
-	parts := $. split: aString.
-	jws := JWSHeader fromJson: (parts at: 1) base64Decoded.
-	self halt.
-		
\ No newline at end of file
diff --git a/source/JSONWebToken-Core.package/JWSCompactSerializer.class/instance/materialize.key..st b/source/JSONWebToken-Core.package/JWSCompactSerializer.class/instance/materialize.key..st
index 144b6ae..1f5ed43 100644
--- a/source/JSONWebToken-Core.package/JWSCompactSerializer.class/instance/materialize.key..st
+++ b/source/JSONWebToken-Core.package/JWSCompactSerializer.class/instance/materialize.key..st
@@ -1,11 +1,3 @@
 reading
 materialize: aString key: aKeyString
-	| parts header jws  |
-	parts := $. split: aString.
-	header := JWSHeader fromJson: (parts at: 1) base64Decoded.
-	jws := JsonWebSignature new
-		key: aKeyString;
-		setProtectedHeader: header.
-	((jws signatureFor: ($. join: { parts first . parts second })) = parts third base64Decoded asByteArray) ifFalse: [
-		Error signal: 'signature does not match' ].
-	^ jws payload: (JWTClaimsSet fromJson: parts second base64Decoded) 
\ No newline at end of file
+	^ self materialize: aString key: aKeyString checkSignature: true 
\ No newline at end of file
diff --git a/source/JSONWebToken-Core.package/JWSCompactSerializer.class/instance/materialize.key.checkSignature..st b/source/JSONWebToken-Core.package/JWSCompactSerializer.class/instance/materialize.key.checkSignature..st
new file mode 100644
index 0000000..c85ef9a
--- /dev/null
+++ b/source/JSONWebToken-Core.package/JWSCompactSerializer.class/instance/materialize.key.checkSignature..st
@@ -0,0 +1,11 @@
+reading
+materialize: aString key: aKeyString checkSignature: checkSignature
+	| parts header jws  |
+	parts := $. split: aString.
+	header := JWSHeader fromJson: (parts at: 1) base64Decoded.
+	jws := JsonWebSignature new
+		key: aKeyString;
+		setProtectedHeader: header.
+	checkSignature ifTrue: [  
+		jws checkSignature: parts  ]. 
+	^ jws payload: (JWTClaimsSet fromJson: parts second base64Decoded) 
\ No newline at end of file
diff --git a/source/JSONWebToken-Core.package/JsonWebSignature.class/class/materializeCompact.key..st b/source/JSONWebToken-Core.package/JsonWebSignature.class/class/materializeCompact.key..st
index 8405185..6d1eef3 100644
--- a/source/JSONWebToken-Core.package/JsonWebSignature.class/class/materializeCompact.key..st
+++ b/source/JSONWebToken-Core.package/JsonWebSignature.class/class/materializeCompact.key..st
@@ -1,4 +1,4 @@
 materializing
 materializeCompact: aString key: aKeyString
-	^ JWSCompactSerializer new materialize: aString key: aKeyString
+	^ self materializeCompact: aString key: aKeyString checkSignature: true
 		
\ No newline at end of file
diff --git a/source/JSONWebToken-Core.package/JsonWebSignature.class/class/materializeCompact.key.checkSignature..st b/source/JSONWebToken-Core.package/JsonWebSignature.class/class/materializeCompact.key.checkSignature..st
new file mode 100644
index 0000000..34db4b8
--- /dev/null
+++ b/source/JSONWebToken-Core.package/JsonWebSignature.class/class/materializeCompact.key.checkSignature..st
@@ -0,0 +1,4 @@
+materializing
+materializeCompact: aString key: aKeyString checkSignature: checkSignature
+	^ JWSCompactSerializer new materialize: aString key: aKeyString checkSignature: checkSignature
+		
\ No newline at end of file
diff --git a/source/JSONWebToken-Core.package/JsonWebSignature.class/instance/algorithm.st b/source/JSONWebToken-Core.package/JsonWebSignature.class/instance/algorithm.st
new file mode 100644
index 0000000..cf71a93
--- /dev/null
+++ b/source/JSONWebToken-Core.package/JsonWebSignature.class/instance/algorithm.st
@@ -0,0 +1,3 @@
+accessing
+algorithm
+	^ self protectedHeader algorithm
\ No newline at end of file
diff --git a/source/JSONWebToken-Core.package/JsonWebSignature.class/instance/checkSignature..st b/source/JSONWebToken-Core.package/JsonWebSignature.class/instance/checkSignature..st
new file mode 100644
index 0000000..c5e9771
--- /dev/null
+++ b/source/JSONWebToken-Core.package/JsonWebSignature.class/instance/checkSignature..st
@@ -0,0 +1,4 @@
+signature
+checkSignature: parts
+	((self signatureFor: ($. join: { parts first . parts second })) = parts third base64Decoded asByteArray) ifFalse: [
+		Error signal: 'signature does not match' ].