Secure Data sharing has become an ubiquitous need. One way of pursuing it is to use Proxy Re-Encryption (PRE), which allows delegation of decryption rights selectively. This work tackles the problem of designing a Proxy Re-Encryption that is unidirectional and CCA-secure in the standard model without pairings. In (Zhang et al., 2013) they propose a solution that makes the Cramer-Shoup encryption scheme publicly verifiable and use their result to construct a CCA secure PRE in the standard model. However, we show that their scheme is vulnerable against adaptive chosen ciphertexts attacks. Then we propose a new construction based on Cramer-Shoup crypto-system (Cramer and Shoup, 1998), that is CCA secure without pairings nor random oracle