/
e4.2.go
58 lines (50 loc) · 1.14 KB
/
e4.2.go
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// e4.2.go prints the SHA256 checksum of it's standard input by default and
// supports command line flags to print the SHA384 or SHA512 checksums instead
// ("-t" for SHA384 and "-f" for SHA512)
package main
import (
"crypto/sha256"
"crypto/sha512"
"flag"
"fmt"
"io/ioutil"
"os"
)
// create flags to call different SHA functions
var flag384 bool
var flag512 bool
func init() {
flag.BoolVar(&flag384, "t", false, "SHA384")
flag.BoolVar(&flag512, "f", false, "SHA256")
}
func main() {
// get input as []byte and pass to SHA functions
in, err := ioutil.ReadAll(os.Stdin)
if err != nil {
fmt.Print(err)
}
flag.Parse()
// create conditions for flags
if !flag384 && !flag512 {
fmt.Printf("SHA256: %d\n", get256(in))
} else if !flag512 {
fmt.Printf("SHA384: %d\n", get384(in))
} else {
fmt.Printf("SHA512: %d\n", get512(in))
}
}
// calculate SHA256 checksum
func get256(in []byte) [32]byte {
sha := sha256.Sum256(in)
return sha
}
// calculate SHA384 checksum
func get384(in []byte) [48]byte {
sha := sha512.Sum384(in)
return sha
}
// calculate SHA512 checksum
func get512(in []byte) [64]byte {
sha := sha512.Sum512(in)
return sha
}