1 files changed, 69 insertions, 0 deletions
diff --git a/Crypto/src/asn1/x9/X9FieldElement.cs b/Crypto/src/asn1/x9/X9FieldElement.cs
new file mode 100644
index 000000000..06fa0e3dc
--- /dev/null
+++ b/Crypto/src/asn1/x9/X9FieldElement.cs
@@ -0,0 +1,69 @@
+using System;
+
+using Org.BouncyCastle.Math;
+using Org.BouncyCastle.Math.EC;
+
+namespace Org.BouncyCastle.Asn1.X9
+{
+ /**
+ * Class for processing an ECFieldElement as a DER object.
+ */
+ public class X9FieldElement
+ : Asn1Encodable
+ {
+ private ECFieldElement f;
+
+ public X9FieldElement(
+ ECFieldElement f)
+ {
+ this.f = f;
+ }
+
+ public X9FieldElement(
+ BigInteger p,
+ Asn1OctetString s)
+ : this(new FpFieldElement(p, new BigInteger(1, s.GetOctets())))
+ {
+ }
+
+ public X9FieldElement(
+ int m,
+ int k1,
+ int k2,
+ int k3,
+ Asn1OctetString s)
+ : this(new F2mFieldElement(m, k1, k2, k3, new BigInteger(1, s.GetOctets())))
+ {
+ }
+
+ public ECFieldElement Value
+ {
+ get { return f; }
+ }
+
+ /**
+ * Produce an object suitable for an Asn1OutputStream.
+ * <pre>
+ * FieldElement ::= OCTET STRING
+ * </pre>
+ * <p>
+ * <ol>
+ * <li> if <i>q</i> is an odd prime then the field element is
+ * processed as an Integer and converted to an octet string
+ * according to x 9.62 4.3.1.</li>
+ * <li> if <i>q</i> is 2<sup>m</sup> then the bit string
+ * contained in the field element is converted into an octet
+ * string with the same ordering padded at the front if necessary.
+ * </li>
+ * </ol>
+ * </p>
+ */
+ public override Asn1Object ToAsn1Object()
+ {
+ int byteCount = X9IntegerConverter.GetByteLength(f);
+ byte[] paddedBigInteger = X9IntegerConverter.IntegerToBytes(f.ToBigInteger(), byteCount);
+
+ return new DerOctetString(paddedBigInteger);
+ }
+ }
+}
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