Package com.nimbusds.jose.crypto.impl

Class ECDSA

java.lang.Object
com.nimbusds.jose.crypto.impl.ECDSA
public class ECDSA extends Object
Elliptic Curve Digital Signature Algorithm (ECDSA) functions and utilities.
Version:
2022-04-22
Author:
Vladimir Dzhuvinov, Aleksei Doroganov

  • Method Details

    • resolveAlgorithm

      public static JWSAlgorithm resolveAlgorithm(ECKey ecKey) throws JOSEException
      Resolves the matching EC DSA algorithm for the specified EC key (public or private).
      Parameters:
      ecKey - The EC key. Must not be null.
      Returns:
      The matching EC DSA algorithm.
      Throws:
      JOSEException - If the elliptic curve of key is not supported.

    • resolveAlgorithm

      public static JWSAlgorithm resolveAlgorithm(Curve curve) throws JOSEException
      Resolves the matching EC DSA algorithm for the specified elliptic curve.
      Parameters:
      curve - The elliptic curve. May be null.
      Returns:
      The matching EC DSA algorithm.
      Throws:
      JOSEException - If the elliptic curve of key is not supported.

    • getSignerAndVerifier

      public static Signature getSignerAndVerifier(JWSAlgorithm alg, Provider jcaProvider) throws JOSEException
      Creates a new JCA signer / verifier for ECDSA.
      Parameters:
      alg - The ECDSA JWS algorithm. Must not be null.
      jcaProvider - The JCA provider, null if not specified.
      Returns:
      The JCA signer / verifier instance.
      Throws:
      JOSEException - If a JCA signer / verifier couldn't be created.

    • getSignatureByteArrayLength

      public static int getSignatureByteArrayLength(JWSAlgorithm alg) throws JOSEException
      Returns the expected signature byte array length (R + S parts) for the specified ECDSA algorithm.
      Parameters:
      alg - The ECDSA algorithm. Must be supported and not null.
      Returns:
      The expected byte array length for the signature.
      Throws:
      JOSEException - If the algorithm is not supported.

    • transcodeSignatureToConcat

      public static byte[] transcodeSignatureToConcat(byte[] derSignature, int outputLength) throws JOSEException
      Transcodes the JCA ASN.1/DER-encoded signature into the concatenated R + S format expected by ECDSA JWS.
      Parameters:
      derSignature - The ASN1./DER-encoded. Must not be null.
      outputLength - The expected length of the ECDSA JWS signature.
      Returns:
      The ECDSA JWS encoded signature.
      Throws:
      JOSEException - If the ASN.1/DER signature format is invalid.

    • transcodeSignatureToDER

      public static byte[] transcodeSignatureToDER(byte[] jwsSignature) throws JOSEException
      Transcodes the ECDSA JWS signature into ASN.1/DER format for use by the JCA verifier.
      Parameters:
      jwsSignature - The JWS signature, consisting of the concatenated R and S values. Must not be null.
      Returns:
      The ASN.1/DER encoded signature.
      Throws:
      JOSEException - If the ECDSA JWS signature format is invalid or conversion failed unexpectedly.

    • ensureLegalSignature

      public static void ensureLegalSignature(byte[] jwsSignature, JWSAlgorithm jwsAlg) throws JOSEException
      Ensures the specified ECDSA signature is legal. Intended to prevent attacks on JCA implementations vulnerable to CVE-2022-21449 and similar bugs.
      Parameters:
      jwsSignature - The JWS signature. Must not be null.
      jwsAlg - The ECDSA JWS algorithm. Must not be null.
      Throws:
      JOSEException - If the signature is found to be illegal, or the JWS algorithm or curve are not supported.