 [semidet]rsa_verify(+Key, 
+Data, +Signature, +Options)
[semidet]rsa_verify(+Key, 
+Data, +Signature, +Options)Options:
sha1,
sha224, sha256, sha384 or sha512. 
The default is the same as for rsa_sign/4. 
This option must match the algorithm that was used for signing. When 
operating with different parties, the used algorithm must be 
communicated over an authenticated channel.hex. 
Alternatives are octet, utf8 and text.