1.对字符串进行hash
大家可以看一下， SHA1 Hashes
Go by Example写道：
The pattern for generating a hash is sha1.New(), sha1.Write(bytes), then sha1.Sum([]byte{}).
附上golang代码
package main import ( "crypto/sha1" "fmt" ) func main() { s := "sha1 this string" h := sha1.New() h.Write([]byte(s)) bs := h.Sum(nil) fmt.Println(s) fmt.Printf("%x\n", bs) }
结果输出为：
sha1 this string
cf23df2207d99a74fbe169e3eba035e633b65d94
而在godoc产生的文档使用io:WriteString代替sha1.Write()，测试2种方法都可以用。
有些文档说，使用io:WriteString，意思更加明显，而且不用像上面要进行类型转换。
h := sha1.New() io.WriteString(h, "His money is twice tainted: 'taint yours and 'taint mine.") fmt.Printf("% x", h.Sum(nil))
说个有趣的现象，使用上面代码产生的hash值和命令行中sha1sum的值不一致。
$echo "sha1 this string" | sha1sum 0faabfb58d5c522f47944173f2953f40ecfc2975 - $ $cat a.txt sha1 this string $sha1sum a.txt 0faabfb58d5c522f47944173f2953f40ecfc2975 a.txt $
可以看到，上面2个结果是一致的，但与我们上面golang代码的输出不一致。
原因是，命令行echo会在字符串后面添加一个换行符，导致整个hash值变化。大家可以自行在golang的代码中，在验证的字符串中添加换行符测试看看。
2.对文本进行hash
参考 google论坛
模式是，os.Open(file), io.Copy(dst,src), sha1.Sum()
摘录2个github代码，代码在原来的基础上有修改。
/* Hash - Guillermo Estrada Simple utility to obtain the MD5 and/or SHA-1 of a file from the command line. package main import ( "io" "os" "fmt" "flag" "crypto/md5" "crypto/sha1" ) func main() { md5f := flag.Bool("md5", false, "-md5 calculate md5 hash of file") sha1f := flag.Bool("sha1", false, "-sha1 calculate sha1 hash of file") flag.Parse() if !*md5f && !*sha1f { fmt.Println("err: No hash specified. Use -md5 or -sha1 or both.") os.Exit(1) } infile, inerr := os.Open(flag.Arg(0)) if inerr == nil { if *md5f { md5h := md5.New() io.Copy(md5h,infile) fmt.Printf("%x %s\n",md5h.Sum(nil), flag.Arg(0)) } if *sha1f { sha1h := sha1.New() io.Copy(sha1h,infile) fmt.Printf("%x %s\n",sha1h.Sum(nil), flag.Arg(0)) } } else { fmt.Println(inerr) os.Exit(1) } }
命令行调用：
#for a in md5 sha1 ; do echo ${a}sum; ./hash -$a /bin/ls; ${a}sum /bin/ls; echo; done md5sum b691e28e120f6989e37c7db21cb51931 /bin/ls b691e28e120f6989e37c7db21cb51931 /bin/ls sha1sum 502202e177bb8677c8c3b059cc1401d1524806c8 /bin/ls 502202e177bb8677c8c3b059cc1401d1524806c8 /bin/ls #
/* Hash - Guillermo Estrada Simple utility to obtain the MD5 and/or SHA-1 of a file from the command line. 2011 Edited: Marko Mikulicic 2011 */ package main import ( "io" "os" "fmt" "flag" "hash" "crypto/md5" "crypto/sha1" "crypto/sha256" "crypto/sha512" //"crypto/ripemd160" ) func main() { algos := [...]string{"md5", "sha1", "sha256", "sha512" } impls := [...]hash.Hash{md5.New(), sha1.New(), sha256.New(), sha512.New() } flags := make([]*bool, len(algos)) for i, a := range algos { flags[i] = flag.Bool(a, false, fmt.Sprintf("-%s calculate %s hash of file", a, a)) } flag.Parse() any := false for _, f := range flags { any = any || *f } if any == false { fmt.Println("err: No hash specified. Please run with --help to see list of supported hash algos") os.Exit(1) } infile, err := os.Open(flag.Arg(0)) if err != nil { fmt.Println(err) os.Exit(1) } writers := make([]io.Writer, 0, len(impls)) for i, flag := range flags { if *flag { writers = append(writers, impls[i]) } } dest := io.MultiWriter(writers...) io.Copy(dest, infile) for i, flag := range flags { if *flag { fmt.Printf("%s: \n%x\n", algos[i], impls[i].Sum(nil)) } } }
命令行调用：
#for a in md5 sha1 sha256 sha512 ; do ./hashes -$a /bin/ls; ${a}sum /bin/ls; echo; done md5: b691e28e120f6989e37c7db21cb51931 b691e28e120f6989e37c7db21cb51931 /bin/ls sha1: 502202e177bb8677c8c3b059cc1401d1524806c8 502202e177bb8677c8c3b059cc1401d1524806c8 /bin/ls sha256: 1e87d99599ddea2a93f060b50a54066e8b756d752158e6147cbb99b06eb11d99 1e87d99599ddea2a93f060b50a54066e8b756d752158e6147cbb99b06eb11d99 /bin/ls sha512: 343b38486ad17c5813026c9df7e1ce7e268d7c64e70439aebddcafdfe10a0dfc9f55bf8169c3e592942f50bb408a852dfd1fb08e0bcadf214bc89dbf72d693f8 343b38486ad17c5813026c9df7e1ce7e268d7c64e70439aebddcafdfe10a0dfc9f55bf8169c3e592942f50bb408a852dfd1fb08e0bcadf214bc89dbf72d693f8 /bin/ls #
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