1 files changed, 58 insertions, 0 deletions

diff --git a/pkix/src/main/java/org/spongycastle/cms/KeyTransRecipientInfoGenerator.java b/pkix/src/main/java/org/spongycastle/cms/KeyTransRecipientInfoGenerator.java
new file mode 100644
index 00000000..c78a4ff8
--- /dev/null
+++ b/pkix/src/main/java/org/spongycastle/cms/KeyTransRecipientInfoGenerator.java
@@ -0,0 +1,58 @@
+package org.spongycastle.cms;
+
+import org.spongycastle.asn1.DEROctetString;
+import org.spongycastle.asn1.cms.IssuerAndSerialNumber;
+import org.spongycastle.asn1.cms.KeyTransRecipientInfo;
+import org.spongycastle.asn1.cms.RecipientIdentifier;
+import org.spongycastle.asn1.cms.RecipientInfo;
+import org.spongycastle.operator.AsymmetricKeyWrapper;
+import org.spongycastle.operator.GenericKey;
+import org.spongycastle.operator.OperatorException;
+
+public abstract class KeyTransRecipientInfoGenerator
+    implements RecipientInfoGenerator
+{
+    protected final AsymmetricKeyWrapper wrapper;
+
+    private IssuerAndSerialNumber issuerAndSerial;
+    private byte[] subjectKeyIdentifier;
+
+    protected KeyTransRecipientInfoGenerator(IssuerAndSerialNumber issuerAndSerial, AsymmetricKeyWrapper wrapper)
+    {
+        this.issuerAndSerial = issuerAndSerial;
+        this.wrapper = wrapper;
+    }
+
+    protected KeyTransRecipientInfoGenerator(byte[] subjectKeyIdentifier, AsymmetricKeyWrapper wrapper)
+    {
+        this.subjectKeyIdentifier = subjectKeyIdentifier;
+        this.wrapper = wrapper;
+    }
+
+    public final RecipientInfo generate(GenericKey contentEncryptionKey)
+        throws CMSException
+    {
+        byte[] encryptedKeyBytes;
+        try
+        {
+            encryptedKeyBytes = wrapper.generateWrappedKey(contentEncryptionKey);
+        }
+        catch (OperatorException e)
+        {
+            throw new CMSException("exception wrapping content key: " + e.getMessage(), e);
+        }
+
+        RecipientIdentifier recipId;
+        if (issuerAndSerial != null)
+        {
+            recipId = new RecipientIdentifier(issuerAndSerial);
+        }
+        else
+        {
+            recipId = new RecipientIdentifier(new DEROctetString(subjectKeyIdentifier));
+        }
+
+        return new RecipientInfo(new KeyTransRecipientInfo(recipId, wrapper.getAlgorithmIdentifier(),
+            new DEROctetString(encryptedKeyBytes)));
+    }
+}
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