digital-signature

问题 The following command generates a signature for an input file: openssl dgst -sha1 -sign privateKey.pem -out signature1 someInputFile The following commands also generates a signature for an input file: openssl dgst -binary -sha1 someInputFile > digest openssl rsautl -sign -in digest -inkey privateKey.pem -out signature2 As far as I know, they should both create the RSA signature of a SHA1 digest of the file. But they don\'t generate the same signature. As a result, the signature generated

问题 I have an app which is signed and several keystore files. I\'d like to update the app, so I need to find out which one of keys was used. How can I match which keystore was used to originally sign my app against various keystores I have on my machine? 回答1: First, unzip the APK and extract the file /META-INF/ANDROID_.RSA (this file may also be CERT.RSA, but there should only be one .RSA file). Then issue this command: keytool -printcert -file ANDROID_.RSA You will get certificate fingerprints

问题 I want to insert blank page at end of the digitally PDF using itext library .and my confusion is adding pages will invalidate the existing signatures? Thank you. 回答1: To put Joeri's answer into context, have a look at the Adobe technical white paper Adobe Acrobat 9 Digital Signatures, Changes and Improvements, especially its section "Allowed and disallowed changes." Here Adobe clarifies the allowed changes (as seen by Acrobat 9 and up) that can be made to a certified or signed document