1 files changed, 34 insertions, 0 deletions
diff --git a/pkix/src/main/java/org/spongycastle/operator/bc/AESUtil.java b/pkix/src/main/java/org/spongycastle/operator/bc/AESUtil.java
new file mode 100644
index 00000000..7abd31be
--- /dev/null
+++ b/pkix/src/main/java/org/spongycastle/operator/bc/AESUtil.java
@@ -0,0 +1,34 @@
+package org.spongycastle.operator.bc;
+
+import org.spongycastle.asn1.ASN1ObjectIdentifier;
+import org.spongycastle.asn1.nist.NISTObjectIdentifiers;
+import org.spongycastle.asn1.x509.AlgorithmIdentifier;
+import org.spongycastle.crypto.params.KeyParameter;
+
+class AESUtil
+{
+    static AlgorithmIdentifier determineKeyEncAlg(KeyParameter key)
+    {
+        int length = key.getKey().length * 8;
+        ASN1ObjectIdentifier wrapOid;
+
+        if (length == 128)
+        {
+            wrapOid = NISTObjectIdentifiers.id_aes128_wrap;
+        }
+        else if (length == 192)
+        {
+            wrapOid = NISTObjectIdentifiers.id_aes192_wrap;
+        }
+        else if (length == 256)
+        {
+            wrapOid = NISTObjectIdentifiers.id_aes256_wrap;
+        }
+        else
+        {
+            throw new IllegalArgumentException("illegal keysize in AES");
+        }
+
+        return new AlgorithmIdentifier(wrapOid); // parameters absent
+    }
+}