| [_SHA1 hashes_](http://en.wikipedia.org/wiki/SHA-1) are frequently used to compute short identities for binary or text blobs. For example, the [git revision control system](http://git-scm.com/) uses SHA1s extensively to identify versioned files and directories. Here's how to compute SHA1 hashes in Go. | ||
package main |
||
| Go implements several hash functions in various `crypto/*` packages. | import ( |
|
"crypto/sha1" |
||
"fmt" |
||
) |
||
func main() { |
||
s := "sha1 this string" |
||
| The pattern for generating a hash is `sha1.New()`, `sha1.Write(bytes)`, then `sha1.Sum([]byte{})`. Here we start with a new hash. | h := sha1.New() |
|
| `Write` expects bytes. If you have a string `s`, use `[]byte(s)` to coerce it to bytes. | h.Write([]byte(s)) |
|
| This gets the finalized hash result as a byte slice. The argument to `Sum` can be used to append to an existing byte slice: it usually isn't needed. | bs := h.Sum(nil) |
|
| SHA1 values are often printed in hex, for example in git commits. Use the `%x` format verb to convert a hash results to a hex string. | fmt.Println(s) |
|
fmt.Printf("%x\n", bs) |
sha1 this string cf23df2207d99a74fbe169e3eba035e633b65d94 |
|
} |