To get a human-readable view of the contents of the certificates:
        
    openssl x509 -in TargetCollidingCertificate1.cer -inform DER -text
    openssl x509 -in TargetCollidingCertificate2.cer -inform DER -text
        
To verify the signature on the two certificates against the CA certificate, 
first convert the certificates to PEM-format
("openssl verify" does not work with the DER format):
        
    openssl x509 -in TargetCollidingCertificate1.cer -inform DER -out TargetCollidingCertificate1.pem
    openssl x509 -in TargetCollidingCertificate2.cer -inform DER -out TargetCollidingCertificate2.pem
    openssl x509 -in MD5CollisionCA.cer -inform DER -out MD5CollisionCA.pem
        
and then do the verification:
        
    openssl verify -CAfile MD5CollisionCA.pem TargetCollidingCertificate1.pem
    openssl verify -CAfile MD5CollisionCA.pem TargetCollidingCertificate2.pem