diff --git a/CHANGELOG.md b/CHANGELOG.md
index 48f85df99..a253ba4b9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,11 @@ FEATURES:
 * builder/amazon/ebs: Ability to specify which availability zone to create
   instance in. [GH-536]
 
+BUG FIXES:
+
+* common/uuid: Use cryptographically secure PRNG when generating
+  UUIDs. [GH-552]
+
 ## 0.3.10 (October 20, 2013)
 
 FEATURES:
diff --git a/common/uuid/uuid.go b/common/uuid/uuid.go
index 496a2f6ef..d8b9830be 100644
--- a/common/uuid/uuid.go
+++ b/common/uuid/uuid.go
@@ -1,8 +1,8 @@
 package uuid
 
 import (
+	"crypto/rand"
 	"fmt"
-	"math/rand"
 	"time"
 )
 
@@ -10,14 +10,15 @@ import (
 // bottom 96 are random.
 func TimeOrderedUUID() string {
 	unix := uint32(time.Now().UTC().Unix())
-	rand1 := rand.Uint32()
-	rand2 := rand.Uint32()
-	rand3 := rand.Uint32()
+
+	b := make([]byte, 12)
+	n, err := rand.Read(b)
+	if n != len(b) {
+		err = fmt.Errorf("Not enough entropy available")
+	}
+	if err != nil {
+		panic(err)
+	}
 	return fmt.Sprintf("%08x-%04x-%04x-%04x-%04x%08x",
-		unix,
-		uint16(rand1>>16),
-		uint16(rand1&0xffff),
-		uint16(rand2>>16),
-		uint16(rand2&0xffff),
-		rand3)
+		unix, b[0:2], b[2:4], b[4:6], b[6:8], b[8:])
 }