Please read all of Jeff's message. As well as checking that OpenSSL is installed, he told you that you need to link against OpenSSL's libcrypto as well as against OpenSSL's libssl. In the linker command you show below, change '-lssl' to '-lssl -lcrypto'.
Regards, jjf From: Amir Reda [mailto:amirale...@gmail.com] Sent: Monday, November 03, 2014 2:43 PM dear sir i already installed ssl lib i use this command amir@amir-Master:~$ sudo apt-get install libssl-dev [sudo] password for amir: Reading package lists... Done Building dependency tree Reading state information... Done libssl-dev is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. amir@amir-Master:~$ as you can see it is already installed are there any solution On Fri, Oct 31, 2014 at 4:14 PM, Jeffrey Walton <HYPERLINK "mailto:noloa...@gmail.com"; \nnoloa...@gmail.com> wrote: On Fri, Oct 31, 2014 at 6:57 AM, Amir Reda <HYPERLINK "mailto:amirale...@gmail.com"amirale...@gmail.com> wrote: > dear all i made a code for sign some data and verify it i am using eclipse > as IDE and ubuntu 13.10 i have linked eclipse with ssl lib and crypto++ > which i use in this code i got an error > > Invoking: Cross G++ Linker > g++ -L/usr/include/openssl -L/usr/include/cryptopp -L/usr/include/crypto++ > -L/usr/include -o "sign" ./src/sign.o -lssl -lcryptopp -lcrypto++ > /usr/bin/ld: ./src/sign.o: undefined reference to symbol > 'RSA_sign@@OPENSSL_1.0.0' > /lib/i386-linux-gnu/libcrypto.so.1.0.0: error adding symbols: DSO missing > from command line > collect2: ld returned 1 exit status Be sure you have the dev package installed for Ubuntu. I think that's 'sudo apt-get install libssl-dev'.(See https://packages.debian.org/search?keywords=libssl-dev). Add '-lss -lcrypto'. They are the OpenSSL libraries. Add them in the order shown. '-lcryptopp -lcrypto++' are Wei Dai's Crypto++ libraries. Are you sure you need them?
