Groovy SSL signature verification: signature length not correct?

Question

I'm trying to verify a message signed with private key, using the provided public key and a signature.

The command line that works like charm is

cat call.blah | openssl dgst -sha256 -verify public-key.pem -signature signature.sig
Verified OK

The public-key.pem has been created from X509 certificate using the command

openssl x509 -pubkey -noout -in x509key.cer > public-key.pem

Now I am trying to mimic that in groovy, here's my code

static void main(String[] args) {

   /* Verify a DSA signature */

    if (args.length != 3) {
        System.out.println("Usage: VerSig publickeyfile signaturefile datafile")
    } else try {

        /* import encoded public key */

        FileInputStream keyfis = new FileInputStream(args[0])

        CertificateFactory f = CertificateFactory.getInstance("X.509")
        X509Certificate certificate = (X509Certificate)f.generateCertificate(keyfis)
        PublicKey pubKey = certificate.getPublicKey()

        /* input the signature bytes */
        FileInputStream sigfis = new FileInputStream(args[1])
        byte[] sigToVerify = new byte[sigfis.available()]
        sigfis.read(sigToVerify)

        sigfis.close()

        /* create a Signature object and initialize it with the public key */
        Signature sig = Signature.getInstance("SHA256withRSA")
        sig.initVerify(pubKey)

        /* Update and verify the data */

        FileInputStream datafis = new FileInputStream(args[2])
        BufferedInputStream bufin = new BufferedInputStream(datafis)

        byte[] buffer = new byte[1024]
        int len
        while (bufin.available() != 0) {
            len = bufin.read(buffer)
            sig.update(buffer, 0, len)
        }

        bufin.close()


        boolean verifies = sig.verify(sigToVerify) // <---- THIS IS WHERE THE ERROR OCCURS

        System.out.println("signature verifies: " + verifies)


    } catch (Exception e) {
        e.printStackTrace()
    }

}

and i'm running this with these parameters

x509key.cer signature.sig call.blah

(it's the X509 certificate, signature and the signed message body)

Getting out the following stacktrace

java.security.SignatureException: Signature length not correct: got 512 but was expecting 256
at sun.security.rsa.RSASignature.engineVerify(RSASignature.java:190)
at java.security.Signature$Delegate.engineVerify(Signature.java:1174)
at java.security.Signature.verify(Signature.java:624)
at java_security_Signature$verify$2.call(Unknown Source)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:45)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:108)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
at VerSig.main(VerSign.groovy:50)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)

What am I doing wrong?

Answer 1

I used the following dependency:

compile 'org.bouncycastle:bcprov-jdk15on:1.50'

and that code

import com.google.common.base.Charsets
import groovy.transform.PackageScope
import org.bouncycastle.util.io.pem.PemReader
import org.springframework.core.io.ClassPathResource

import java.security.Key
import java.security.KeyFactory
import java.security.Signature
import java.security.spec.KeySpec
import java.security.spec.PKCS8EncodedKeySpec
import java.security.spec.X509EncodedKeySpec

import static org.apache.commons.codec.binary.Base64.decodeBase64
import static org.apache.commons.codec.binary.Base64.encodeBase64String
import static org.apache.commons.io.IOUtils.toByteArray

@PackageScope
class MessageSigner {

    public static final String KEY_TYPE = "RSA"
    public static final String SIGNATURE_ALGORITHM = "SHA1withRSA"
    private final ClassPathResource privateKey
    private final ClassPathResource publicKey

    MessageSigner(ClassPathResource privateKey, ClassPathResource publicKey) {
            this.privateKey = privateKey
            this.publicKey = publicKey
    }

    String sign(String body) {
            KeyFactory keyFactory = KeyFactory.getInstance(KEY_TYPE)
            KeySpec keySpec = new PKCS8EncodedKeySpec(toByteArray(privateKey.inputStream))
            Key key = keyFactory.generatePrivate(keySpec)
            Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM)
            signature.initSign(key)
            signature.update(body.bytes)
            return encodeBase64String(signature.sign())
    }

    boolean verify(String body, String signatureFromTrustly) {
            PemReader reader = new PemReader(new InputStreamReader(publicKey.inputStream))
            byte[] pubKey = reader.readPemObject().getContent()
            X509EncodedKeySpec keySpec = new X509EncodedKeySpec(pubKey)
            KeyFactory keyFactory = KeyFactory.getInstance(KEY_TYPE)
            Key key = keyFactory.generatePublic(keySpec)
            Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM)
            signature.initVerify(key)
            byte[] bodyBytes = body.getBytes(Charsets.UTF_8)
            signature.update(bodyBytes)
            return signature.verify(decodeBase64(signatureFromTrustly))
    }

}

For signing and verificaiton