1 files changed, 139 insertions, 0 deletions
diff --git a/pkix/src/main/java/org/spongycastle/cms/SignerInfoGeneratorBuilder.java b/pkix/src/main/java/org/spongycastle/cms/SignerInfoGeneratorBuilder.java
new file mode 100644
index 00000000..a33005e0
--- /dev/null
+++ b/pkix/src/main/java/org/spongycastle/cms/SignerInfoGeneratorBuilder.java
@@ -0,0 +1,139 @@
+package org.spongycastle.cms;
+
+import org.spongycastle.asn1.DEROctetString;
+import org.spongycastle.asn1.cms.IssuerAndSerialNumber;
+import org.spongycastle.asn1.cms.SignerIdentifier;
+import org.spongycastle.cert.X509CertificateHolder;
+import org.spongycastle.operator.ContentSigner;
+import org.spongycastle.operator.DigestCalculatorProvider;
+import org.spongycastle.operator.OperatorCreationException;
+
+/**
+ * Builder for SignerInfo generator objects.
+ */
+public class SignerInfoGeneratorBuilder
+{
+    private DigestCalculatorProvider digestProvider;
+    private boolean directSignature;
+    private CMSAttributeTableGenerator signedGen;
+    private CMSAttributeTableGenerator unsignedGen;
+    private CMSSignatureEncryptionAlgorithmFinder sigEncAlgFinder;
+
+    /**
+     *  Base constructor.
+     *
+     * @param digestProvider  a provider of digest calculators for the algorithms required in the signature and attribute calculations.
+     */
+    public SignerInfoGeneratorBuilder(DigestCalculatorProvider digestProvider)
+    {
+        this(digestProvider, new DefaultCMSSignatureEncryptionAlgorithmFinder());
+    }
+
+        /**
+     *  Base constructor.
+     *
+     * @param digestProvider  a provider of digest calculators for the algorithms required in the signature and attribute calculations.
+     */
+    public SignerInfoGeneratorBuilder(DigestCalculatorProvider digestProvider, CMSSignatureEncryptionAlgorithmFinder sigEncAlgFinder)
+    {
+        this.digestProvider = digestProvider;
+        this.sigEncAlgFinder = sigEncAlgFinder;
+    }
+
+    /**
+     * If the passed in flag is true, the signer signature will be based on the data, not
+     * a collection of signed attributes, and no signed attributes will be included.
+     *
+     * @return the builder object
+     */
+    public SignerInfoGeneratorBuilder setDirectSignature(boolean hasNoSignedAttributes)
+    {
+        this.directSignature = hasNoSignedAttributes;
+
+        return this;
+    }
+
+    /**
+     *  Provide a custom signed attribute generator.
+     *
+     * @param signedGen a generator of signed attributes.
+     * @return the builder object
+     */
+    public SignerInfoGeneratorBuilder setSignedAttributeGenerator(CMSAttributeTableGenerator signedGen)
+    {
+        this.signedGen = signedGen;
+
+        return this;
+    }
+
+    /**
+     * Provide a generator of unsigned attributes.
+     *
+     * @param unsignedGen  a generator for signed attributes.
+     * @return the builder object
+     */
+    public SignerInfoGeneratorBuilder setUnsignedAttributeGenerator(CMSAttributeTableGenerator unsignedGen)
+    {
+        this.unsignedGen = unsignedGen;
+
+        return this;
+    }
+
+    /**
+     * Build a generator with the passed in certHolder issuer and serial number as the signerIdentifier.
+     *
+     * @param contentSigner  operator for generating the final signature in the SignerInfo with.
+     * @param certHolder  carrier for the X.509 certificate related to the contentSigner.
+     * @return  a SignerInfoGenerator
+     * @throws OperatorCreationException   if the generator cannot be built.
+     */
+    public SignerInfoGenerator build(ContentSigner contentSigner, X509CertificateHolder certHolder)
+        throws OperatorCreationException
+    {
+        SignerIdentifier sigId = new SignerIdentifier(new IssuerAndSerialNumber(certHolder.toASN1Structure()));
+
+        SignerInfoGenerator sigInfoGen = createGenerator(contentSigner, sigId);
+
+        sigInfoGen.setAssociatedCertificate(certHolder);
+
+        return sigInfoGen;
+    }
+
+    /**
+     * Build a generator with the passed in subjectKeyIdentifier as the signerIdentifier. If used  you should
+     * try to follow the calculation described in RFC 5280 section 4.2.1.2.
+     *
+     * @param contentSigner  operator for generating the final signature in the SignerInfo with.
+     * @param subjectKeyIdentifier    key identifier to identify the public key for verifying the signature.
+     * @return  a SignerInfoGenerator
+     * @throws OperatorCreationException if the generator cannot be built.
+     */
+    public SignerInfoGenerator build(ContentSigner contentSigner, byte[] subjectKeyIdentifier)
+        throws OperatorCreationException
+    {
+        SignerIdentifier sigId = new SignerIdentifier(new DEROctetString(subjectKeyIdentifier));
+
+        return createGenerator(contentSigner, sigId);
+    }
+
+    private SignerInfoGenerator createGenerator(ContentSigner contentSigner, SignerIdentifier sigId)
+        throws OperatorCreationException
+    {
+        if (directSignature)
+        {
+            return new SignerInfoGenerator(sigId, contentSigner, digestProvider, sigEncAlgFinder, true);
+        }
+
+        if (signedGen != null || unsignedGen != null)
+        {
+            if (signedGen == null)
+            {
+                signedGen = new DefaultSignedAttributeTableGenerator();
+            }
+
+            return new SignerInfoGenerator(sigId, contentSigner, digestProvider, sigEncAlgFinder, signedGen, unsignedGen);
+        }
+        
+        return new SignerInfoGenerator(sigId, contentSigner, digestProvider, sigEncAlgFinder);
+    }
+}