diff options
Diffstat (limited to 'envelope/main.cpp')
| -rw-r--r-- | envelope/main.cpp | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/envelope/main.cpp b/envelope/main.cpp new file mode 100644 index 0000000..49b41ff --- /dev/null +++ b/envelope/main.cpp @@ -0,0 +1,97 @@ +#include <iostream> +#include <cstdlib> +#include "../base64.h" +#include "../envelope.h" + +using namespace std; + +const char *progname="envelope"; + +void usage(){ + cerr<<"Usage: " <<endl + <<" "<<progname<<" -k <keylength> Generate a key with the given number of bits" <<endl + <<" "<<progname<<" -e <pubkey> Encrypt text on standard input" <<endl + <<" "<<progname<<" -d <privkey> Decrypt text on standard input" <<endl + <<endl + <<"The program first encrypts the plaintext using 256-bit AES CBC with a randomly" <<endl + <<"generated key, and then encrypts the key using RSA, with the specified key." <<endl + <<"All RSA keys are encoded in base64 in an internal format." <<endl + <<endl + <<"The <keylength> used for RSA key generation is the number of bits in the" <<endl + <<"modulus. Advised for security is at least 2048, but that might take a while to" <<endl + <<"generate (be patient...). (Note: duration of key generation has *absolutely no*" <<endl + <<"meaning as to the strength of the key.) There is no restriction to powers of two"<<endl + <<"in the key length (or any other special class of numbers), but stay above 512," <<endl + <<"or the AES key might not fit." <<endl + <<endl + <<" -k The public and private keys are printed on standard output, separated by" <<endl + <<" newlines. Comments are on standard error." <<endl + <<" -e Text to encrypt is expected on standard input; the public key of the" <<endl + <<" recipient is a command-line argument. Encrypted text is in base64 on" <<endl + <<" standard output." <<endl + <<" -d Text to decrypt is expected on standard input, in the base64 form that is" <<endl + <<" outputted by the -e function. your private key is a command-line argument."<<endl + <<" Decrypted text is on standard output." <<endl; +} + +void mode_keygen(int keylength){ + if(keylength<512){ + cerr<<"Key length too small, please specify length >= 512"<<endl; + exit(1); + } + if(keylength>8192){ + cerr<<"Key length too large, please specify length <= 8192"<<endl; + exit(1); + } + pair<RSA::Key,RSA::Key> keyset=RSA::genkeys(keylength); + cerr<<"Public key:"<<endl; + cout<<RSA::exportKey(keyset.first)<<endl; + cerr<<"Private key:"<<endl; + cout<<RSA::exportKey(keyset.second)<<endl; +} + +void mode_encrypt(const string &pubkeyrepr){ + RSA::Key key(RSA::importKey(pubkeyrepr)); + string data; + char buf[1024]; + while(cin){ + cin.read(buf,sizeof(buf)); + int nread=cin.gcount(); + if(nread==0)continue; + data.append(buf,nread); + } + cout<<Base64::encode(Envelope::encrypt(data,key))<<endl; +} + +void mode_decrypt(const string &privkeyrepr){ + RSA::Key key(RSA::importKey(privkeyrepr)); + string data; + char buf[1024]; + while(cin){ + cin.read(buf,sizeof(buf)); + int nread=cin.gcount(); + if(nread==0)continue; + data.append(buf,nread); + } + cout<<Envelope::decrypt(Base64::decode(data),key)<<flush; +} + +int main(int argc,char **argv){ + if(argc==3&&strcmp(argv[1],"-k")==0){ + char *endp; + int keylength=strtol(argv[2],&endp,10); + if(!argv[2][0]||*endp){ + cerr<<"Invalid number '"<<argv[2]<<"'"<<endl; + usage(); + return 1; + } + mode_keygen(keylength); + } else if(argc==3&&strcmp(argv[1],"-e")==0){ + mode_encrypt(argv[2]); + } else if(argc==3&&strcmp(argv[1],"-d")==0){ + mode_decrypt(argv[2]); + } else { + usage(); + return 1; + } +} |