diff --git a/boot/boot.js b/boot/boot.js
index 64cedab77..dad30ec14 100644
--- a/boot/boot.js
+++ b/boot/boot.js
@@ -786,6 +786,7 @@ $tw.utils.Crypto = function() {
 			}
 			return outputText;
 		};
+	$tw.sjcl = sjcl;
 	this.setPassword = function(newPassword) {
 		currentPassword = newPassword;
 		this.updateCryptoStateTiddler();
diff --git a/core/modules/filters/crypto.js b/core/modules/filters/crypto.js
index 24f1a0df9..0b51281ae 100644
--- a/core/modules/filters/crypto.js
+++ b/core/modules/filters/crypto.js
@@ -16,7 +16,7 @@ exports.sha256 = function(source,operator,options) {
 	var results = [],
 		length = parseInt(operator.operand,10) || 20,
 		sha256 = function(text) {
-			return sjcl.codec.hex.fromBits(sjcl.hash.sha256.hash(text)).substr(0,length);
+			return $tw.sjcl.codec.hex.fromBits($tw.sjcl.hash.sha256.hash(text)).substr(0,length);
 		};
 	source(function(tiddler,title) {
 		results.push(sha256(title));