Package org.bitcoinj.crypto

Class ECKey.ECDSASignature

java.lang.Object
org.bitcoinj.crypto.ECKey.ECDSASignature
Direct Known Subclasses:
TransactionSignature
Enclosing class:
ECKey
public static class ECKey.ECDSASignature extends Object
Groups the two components that make up a signature, and provides a way to encode to DER form, which is how ECDSA signatures are represented when embedded in other data structures in the Bitcoin protocol. The raw components can be useful for doing further EC maths on them.

  • Field Details

    • r

      public final BigInteger r
      The two components of the signature.

    • s

      public final BigInteger s
      The two components of the signature.

  • Constructor Details

    • ECDSASignature

      public ECDSASignature(BigInteger r, BigInteger s)
      Constructs a signature with the given components. Does NOT automatically canonicalise the signature.

  • Method Details

    • isCanonical

      public boolean isCanonical()
      Returns true if the S component is "low", that means it is below ECKey.HALF_CURVE_ORDER. See BIP62.

    • toCanonicalised

      public ECKey.ECDSASignature toCanonicalised()
      Will automatically adjust the S component to be less than or equal to half the curve order, if necessary. This is required because for every signature (r,s) the signature (r, -s (mod N)) is a valid signature of the same message. However, we dislike the ability to modify the bits of a Bitcoin transaction after it's been signed, as that violates various assumed invariants. Thus in future only one of those forms will be considered legal and the other will be banned.

    • encodeToDER

      public byte[] encodeToDER()
      DER is an international standard for serializing data structures which is widely used in cryptography. It's somewhat like protocol buffers but less convenient. This method returns a standard DER encoding of the signature, as recognized by OpenSSL and other libraries.

    • decodeFromDER

      public static ECKey.ECDSASignature decodeFromDER(byte[] bytes) throws SignatureDecodeException
      Throws:
      SignatureDecodeException - if the signature is unparseable in some way.

    • derByteStream

      protected ByteArrayOutputStream derByteStream() throws IOException
      Throws:
      IOException

    • equals

      public boolean equals(Object o)
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object