Certificate Key Extractor

CertoKey.java is a simple Java application which reads an X.509 v3 certificate file, displays the basic certificate contents using Certificate.toString(), reads the certificate PublicKey and signer's (issuer's) Signature and writes:

the X.509 encoded SubjectPublicKeyInfo file as '_subjectpublickeyinfo'
the corresponding CryptoAPI PUBLICKEYBLOB file as "_publickeyblob"
the pkcs#1 version 1.5 certificate signature as "_certsignature"

    java CertoKey  somecertificate.cer

Java X509Certificate Class