请记住，RSA并非设计为分组密码。通常，RSA用于加密对称密钥，然后将其用于加密数据。考虑到这一点，下面是一个程序，该程序可以使用RSA私钥来加密可以自己解密的数据：
package mainimport ( "crypto/rand" "crypto/rsa" "crypto/sha1" "crypto/x509" "encoding/pem" "flag" "io/ioutil" "log")// Command-line flagsvar ( keyFile = flag.String("key", "id_rsa", "Path to RSA private key") inFile = flag.String("in", "in.txt", "Path to input file") outFile = flag.String("out", "out.txt", "Path to output file") label = flag.String("label", "", "Label to use (filename by default)") decrypt = flag.Bool("decrypt", false, "Decrypt instead of encrypting"))func main() { flag.Parse() // Read the input file in, err := ioutil.ReadFile(*inFile) if err != nil { log.Fatalf("input file: %s", err) } // Read the private key pemData, err := ioutil.ReadFile(*keyFile) if err != nil { log.Fatalf("read key file: %s", err) } // Extract the PEM-enpred data block block, _ := pem.Depre(pemData) if block == nil { log.Fatalf("bad key data: %s", "not PEM-enpred") } if got, want := block.Type, "RSA PRIVATE KEY"; got != want { log.Fatalf("unknown key type %q, want %q", got, want) } // Depre the RSA private key priv, err := x509.ParsePKCS1PrivateKey(block.Bytes) if err != nil { log.Fatalf("bad private key: %s", err) } var out []byte if *decrypt { if *label == "" { *label = *outFile } // Decrypt the data out, err = rsa.DecryptOAEP(sha1.New(), rand.Reader, priv, in, []byte(*label)) if err != nil { log.Fatalf("decrypt: %s", err) } } else { if *label == "" { *label = *inFile } out, err = rsa.EncryptOAEP(sha1.New(), rand.Reader, &priv.PublicKey, in, []byte(*label)) if err != nil { log.Fatalf("encrypt: %s", err) } } // Write data to output file if err := ioutil.WriteFile(*outFile, out, 0600); err != nil { log.Fatalf("write output: %s", err) }}
