error when linking with OpenSSL library dynamically

[martin.vegter9@xxxxxxxxx (Martin Vegter)]

Hello,

I have a C program, which is using AES routines from the OpenSSL
library. I have the necessary library installed (libssl-dev
1.0.1e-2+deb7u19):

  $ ls /usr/lib/x86_64-linux-gnu/libcrypto.*
  /usr/lib/x86_64-linux-gnu/libcrypto.a
  /usr/lib/x86_64-linux-gnu/libcrypto.so
  /usr/lib/x86_64-linux-gnu/libcrypto.so.1.0.0

I can compile my program statically:

  gcc -s -o aes aes.c /usr/lib/x86_64-linux-gnu/libcrypto.a

but when i try to compile it dynamically, I get following error:

  $ gcc -s -o aes aes.c -lcrypto
  /tmp/ccofFr4N.o: In function `encrypt':
  aes.c:(.text+0x9f): undefined reference to `aesni_set_encrypt_key'
  aes.c:(.text+0xd9): undefined reference to `aesni_cbc_encrypt'
  aes.c:(.text+0x1a0): undefined reference to `aesni_cbc_encrypt'
  /tmp/ccofFr4N.o: In function `decrypt':
  aes.c:(.text+0x2d4): undefined reference to `aesni_set_decrypt_key'
  aes.c:(.text+0x31e): undefined reference to `aesni_cbc_encrypt'
  collect2: error: ld returned 1 exit status

I noticed the following:

  $ grep aesni_set_encrypt_key /usr/lib/x86_64-linux-gnu/libcrypto.*
  Binary file /usr/lib/x86_64-linux-gnu/libcrypto.a matches

Is it possible, that libcrypto.so does not contain the functions,
while libcrypto.a does ?

could somebody please advise how I can compile my program dynamically ?