1 files changed, 152 insertions, 0 deletions
diff --git a/pg/src/main/j2me/org/spongycastle/openpgp/PGPUtil.java b/pg/src/main/j2me/org/spongycastle/openpgp/PGPUtil.java
new file mode 100644
index 00000000..6bff42d0
--- /dev/null
+++ b/pg/src/main/j2me/org/spongycastle/openpgp/PGPUtil.java
@@ -0,0 +1,152 @@
+package org.spongycastle.openpgp;
+
+import java.io.IOException;
+import java.security.SecureRandom;
+
+import org.spongycastle.asn1.ASN1InputStream;
+import org.spongycastle.asn1.ASN1Sequence;
+import org.spongycastle.asn1.ASN1Integer;
+import org.spongycastle.bcpg.HashAlgorithmTags;
+import org.spongycastle.bcpg.MPInteger;
+import org.spongycastle.bcpg.PublicKeyAlgorithmTags;
+import org.spongycastle.bcpg.SymmetricKeyAlgorithmTags;
+
+/**
+ * Basic utility class
+ */
+public class PGPUtil
+    implements HashAlgorithmTags
+{
+    static MPInteger[] dsaSigToMpi(
+        byte[] encoding) 
+        throws PGPException
+    {
+        ASN1InputStream aIn = new ASN1InputStream(encoding);
+
+        ASN1Integer i1;
+        ASN1Integer i2;
+
+        try
+        {
+            ASN1Sequence s = (ASN1Sequence)aIn.readObject();
+
+            i1 = (ASN1Integer)s.getObjectAt(0);
+            i2 = (ASN1Integer)s.getObjectAt(1);
+        }
+        catch (IOException e)
+        {
+            throw new PGPException("exception encoding signature", e);
+        }
+
+        MPInteger[] values = new MPInteger[2];
+        
+        values[0] = new MPInteger(i1.getValue());
+        values[1] = new MPInteger(i2.getValue());
+        
+        return values;
+    }
+    
+    static String getDigestName(
+        int        hashAlgorithm)
+        throws PGPException
+    {
+        switch (hashAlgorithm)
+        {
+        case HashAlgorithmTags.SHA1:
+            return "SHA1";
+        case HashAlgorithmTags.MD2:
+            return "MD2";
+        case HashAlgorithmTags.MD5:
+            return "MD5";
+        case HashAlgorithmTags.RIPEMD160:
+            return "RIPEMD160";
+        case HashAlgorithmTags.SHA256:
+            return "SHA256";
+        case HashAlgorithmTags.SHA384:
+            return "SHA384";
+        case HashAlgorithmTags.SHA512:
+            return "SHA512";
+        case HashAlgorithmTags.SHA224:
+            return "SHA224";
+        default:
+            throw new PGPException("unknown hash algorithm tag in getDigestName: " + hashAlgorithm);
+        }
+    }
+    
+    static String getSignatureName(
+        int        keyAlgorithm,
+        int        hashAlgorithm)
+        throws PGPException
+    {
+        String     encAlg;
+                
+        switch (keyAlgorithm)
+        {
+        case PublicKeyAlgorithmTags.RSA_GENERAL:
+        case PublicKeyAlgorithmTags.RSA_SIGN:
+            encAlg = "RSA";
+            break;
+        case PublicKeyAlgorithmTags.DSA:
+            encAlg = "DSA";
+            break;
+        case PublicKeyAlgorithmTags.ELGAMAL_ENCRYPT: // in some malformed cases.
+        case PublicKeyAlgorithmTags.ELGAMAL_GENERAL:
+            encAlg = "ElGamal";
+            break;
+        default:
+            throw new PGPException("unknown algorithm tag in signature:" + keyAlgorithm);
+        }
+
+        return getDigestName(hashAlgorithm) + "with" + encAlg;
+    }
+
+    public static byte[] makeRandomKey(
+        int             algorithm,
+        SecureRandom    random) 
+        throws PGPException
+    {
+        int        keySize = 0;
+        
+        switch (algorithm)
+        {
+        case SymmetricKeyAlgorithmTags.TRIPLE_DES:
+            keySize = 192;
+            break;
+        case SymmetricKeyAlgorithmTags.IDEA:
+            keySize = 128;
+            break;
+        case SymmetricKeyAlgorithmTags.CAST5:
+            keySize = 128;
+            break;
+        case SymmetricKeyAlgorithmTags.BLOWFISH:
+            keySize = 128;
+            break;
+        case SymmetricKeyAlgorithmTags.SAFER:
+            keySize = 128;
+            break;
+        case SymmetricKeyAlgorithmTags.DES:
+            keySize = 64;
+            break;
+        case SymmetricKeyAlgorithmTags.AES_128:
+            keySize = 128;
+            break;
+        case SymmetricKeyAlgorithmTags.AES_192:
+            keySize = 192;
+            break;
+        case SymmetricKeyAlgorithmTags.AES_256:
+            keySize = 256;
+            break;
+        case SymmetricKeyAlgorithmTags.TWOFISH:
+            keySize = 256;
+            break;
+        default:
+            throw new PGPException("unknown symmetric algorithm: " + algorithm);
+        }
+        
+        byte[]    keyBytes = new byte[(keySize + 7) / 8];
+        
+        random.nextBytes(keyBytes);
+        
+        return keyBytes;
+    }
+}