1 files changed, 29 insertions, 50 deletions
diff --git a/crypto/src/asn1/cms/PasswordRecipientInfo.cs b/crypto/src/asn1/cms/PasswordRecipientInfo.cs
index 5fac434ca..41ab686ef 100644
--- a/crypto/src/asn1/cms/PasswordRecipientInfo.cs
+++ b/crypto/src/asn1/cms/PasswordRecipientInfo.cs
@@ -25,68 +25,46 @@ namespace Org.BouncyCastle.Asn1.Cms
 #pragma warning restore CS0618 // Type or member is obsolete
         }
 
-        private readonly DerInteger				version;
-        private readonly AlgorithmIdentifier	keyDerivationAlgorithm;
-        private readonly AlgorithmIdentifier	keyEncryptionAlgorithm;
-        private readonly Asn1OctetString		encryptedKey;
+        private readonly DerInteger m_version;
+        private readonly AlgorithmIdentifier m_keyDerivationAlgorithm;
+        private readonly AlgorithmIdentifier m_keyEncryptionAlgorithm;
+        private readonly Asn1OctetString m_encryptedKey;
 
-		public PasswordRecipientInfo(
-            AlgorithmIdentifier	keyEncryptionAlgorithm,
-            Asn1OctetString		encryptedKey)
+        public PasswordRecipientInfo(AlgorithmIdentifier keyEncryptionAlgorithm, Asn1OctetString encryptedKey)
+            : this(keyDerivationAlgorithm: null, keyEncryptionAlgorithm, encryptedKey)
         {
-            this.version = DerInteger.Zero;
-            this.keyEncryptionAlgorithm = keyEncryptionAlgorithm;
-            this.encryptedKey = encryptedKey;
         }
 
-		public PasswordRecipientInfo(
-			AlgorithmIdentifier	keyDerivationAlgorithm,
-			AlgorithmIdentifier	keyEncryptionAlgorithm,
-			Asn1OctetString		encryptedKey)
+		public PasswordRecipientInfo(AlgorithmIdentifier keyDerivationAlgorithm,
+            AlgorithmIdentifier keyEncryptionAlgorithm, Asn1OctetString encryptedKey)
 		{
-			this.version = DerInteger.Zero;
-			this.keyDerivationAlgorithm = keyDerivationAlgorithm;
-			this.keyEncryptionAlgorithm = keyEncryptionAlgorithm;
-			this.encryptedKey = encryptedKey;
+            m_version = DerInteger.Zero;
+            m_keyDerivationAlgorithm = keyDerivationAlgorithm;
+            m_keyEncryptionAlgorithm = keyEncryptionAlgorithm ?? throw new ArgumentNullException(nameof(keyEncryptionAlgorithm));
+            m_encryptedKey = encryptedKey ?? throw new ArgumentNullException(nameof(encryptedKey));
 		}
 
         [Obsolete("Use 'GetInstance' instead")]
         public PasswordRecipientInfo(Asn1Sequence seq)
         {
-            version = (DerInteger)seq[0];
+            int count = seq.Count, pos = 0;
+            if (count < 3 || count > 4)
+                throw new ArgumentException("Bad sequence size: " + count, nameof(seq));
 
-			if (seq[1] is Asn1TaggedObject taggedObject)
-            {
-                keyDerivationAlgorithm = AlgorithmIdentifier.GetInstance(taggedObject, false);
-                keyEncryptionAlgorithm = AlgorithmIdentifier.GetInstance(seq[2]);
-                encryptedKey = (Asn1OctetString)seq[3];
-            }
-            else
-            {
-                keyEncryptionAlgorithm = AlgorithmIdentifier.GetInstance(seq[1]);
-                encryptedKey = (Asn1OctetString)seq[2];
-            }
+            m_version = DerInteger.GetInstance(seq[pos++]);
+            m_keyDerivationAlgorithm = Asn1Utilities.ReadOptionalContextTagged(seq, ref pos, 0, false,
+                AlgorithmIdentifier.GetInstance);
+            m_keyEncryptionAlgorithm = AlgorithmIdentifier.GetInstance(seq[pos++]);
+            m_encryptedKey = Asn1OctetString.GetInstance(seq[pos++]);
         }
 
-        public DerInteger Version
-		{
-			get { return version; }
-		}
+        public DerInteger Version => m_version;
 
-		public AlgorithmIdentifier KeyDerivationAlgorithm
-		{
-			get { return keyDerivationAlgorithm; }
-		}
+        public AlgorithmIdentifier KeyDerivationAlgorithm => m_keyDerivationAlgorithm;
 
-		public AlgorithmIdentifier KeyEncryptionAlgorithm
-		{
-			get { return keyEncryptionAlgorithm; }
-		}
+        public AlgorithmIdentifier KeyEncryptionAlgorithm => m_keyEncryptionAlgorithm;
 
-		public Asn1OctetString EncryptedKey
-		{
-			get { return encryptedKey; }
-		}
+        public Asn1OctetString EncryptedKey => m_encryptedKey;
 
 		/**
          * Produce an object suitable for an Asn1OutputStream.
@@ -101,10 +79,11 @@ namespace Org.BouncyCastle.Asn1.Cms
          */
         public override Asn1Object ToAsn1Object()
         {
-            Asn1EncodableVector v = new Asn1EncodableVector(version);
-            v.AddOptionalTagged(false, 0, keyDerivationAlgorithm);
-			v.Add(keyEncryptionAlgorithm, encryptedKey);
-			return new DerSequence(v);
+            if (m_keyDerivationAlgorithm == null)
+                return new DerSequence(m_version, m_keyEncryptionAlgorithm, m_encryptedKey);
+
+            return new DerSequence(m_version, new DerTaggedObject(false, 0, m_keyDerivationAlgorithm),
+                m_keyEncryptionAlgorithm, m_encryptedKey);
         }
     }
 }