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Diffstat (limited to 'src/pkg/crypto/cipher/example_test.go')
-rw-r--r--src/pkg/crypto/cipher/example_test.go283
1 files changed, 0 insertions, 283 deletions
diff --git a/src/pkg/crypto/cipher/example_test.go b/src/pkg/crypto/cipher/example_test.go
deleted file mode 100644
index 373f6791b..000000000
--- a/src/pkg/crypto/cipher/example_test.go
+++ /dev/null
@@ -1,283 +0,0 @@
-// Copyright 2012 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package cipher_test
-
-import (
- "crypto/aes"
- "crypto/cipher"
- "crypto/rand"
- "encoding/hex"
- "fmt"
- "io"
- "os"
-)
-
-func ExampleNewCBCDecrypter() {
- key := []byte("example key 1234")
- ciphertext, _ := hex.DecodeString("f363f3ccdcb12bb883abf484ba77d9cd7d32b5baecb3d4b1b3e0e4beffdb3ded")
-
- block, err := aes.NewCipher(key)
- if err != nil {
- panic(err)
- }
-
- // The IV needs to be unique, but not secure. Therefore it's common to
- // include it at the beginning of the ciphertext.
- if len(ciphertext) < aes.BlockSize {
- panic("ciphertext too short")
- }
- iv := ciphertext[:aes.BlockSize]
- ciphertext = ciphertext[aes.BlockSize:]
-
- // CBC mode always works in whole blocks.
- if len(ciphertext)%aes.BlockSize != 0 {
- panic("ciphertext is not a multiple of the block size")
- }
-
- mode := cipher.NewCBCDecrypter(block, iv)
-
- // CryptBlocks can work in-place if the two arguments are the same.
- mode.CryptBlocks(ciphertext, ciphertext)
-
- // If the original plaintext lengths are not a multiple of the block
- // size, padding would have to be added when encrypting, which would be
- // removed at this point. For an example, see
- // https://tools.ietf.org/html/rfc5246#section-6.2.3.2. However, it's
- // critical to note that ciphertexts must be authenticated (i.e. by
- // using crypto/hmac) before being decrypted in order to avoid creating
- // a padding oracle.
-
- fmt.Printf("%s\n", ciphertext)
- // Output: exampleplaintext
-}
-
-func ExampleNewCBCEncrypter() {
- key := []byte("example key 1234")
- plaintext := []byte("exampleplaintext")
-
- // CBC mode works on blocks so plaintexts may need to be padded to the
- // next whole block. For an example of such padding, see
- // https://tools.ietf.org/html/rfc5246#section-6.2.3.2. Here we'll
- // assume that the plaintext is already of the correct length.
- if len(plaintext)%aes.BlockSize != 0 {
- panic("plaintext is not a multiple of the block size")
- }
-
- block, err := aes.NewCipher(key)
- if err != nil {
- panic(err)
- }
-
- // The IV needs to be unique, but not secure. Therefore it's common to
- // include it at the beginning of the ciphertext.
- ciphertext := make([]byte, aes.BlockSize+len(plaintext))
- iv := ciphertext[:aes.BlockSize]
- if _, err := io.ReadFull(rand.Reader, iv); err != nil {
- panic(err)
- }
-
- mode := cipher.NewCBCEncrypter(block, iv)
- mode.CryptBlocks(ciphertext[aes.BlockSize:], plaintext)
-
- // It's important to remember that ciphertexts must be authenticated
- // (i.e. by using crypto/hmac) as well as being encrypted in order to
- // be secure.
-
- fmt.Printf("%x\n", ciphertext)
-}
-
-func ExampleNewCFBDecrypter() {
- key := []byte("example key 1234")
- ciphertext, _ := hex.DecodeString("22277966616d9bc47177bd02603d08c9a67d5380d0fe8cf3b44438dff7b9")
-
- block, err := aes.NewCipher(key)
- if err != nil {
- panic(err)
- }
-
- // The IV needs to be unique, but not secure. Therefore it's common to
- // include it at the beginning of the ciphertext.
- if len(ciphertext) < aes.BlockSize {
- panic("ciphertext too short")
- }
- iv := ciphertext[:aes.BlockSize]
- ciphertext = ciphertext[aes.BlockSize:]
-
- stream := cipher.NewCFBDecrypter(block, iv)
-
- // XORKeyStream can work in-place if the two arguments are the same.
- stream.XORKeyStream(ciphertext, ciphertext)
- fmt.Printf("%s", ciphertext)
- // Output: some plaintext
-}
-
-func ExampleNewCFBEncrypter() {
- key := []byte("example key 1234")
- plaintext := []byte("some plaintext")
-
- block, err := aes.NewCipher(key)
- if err != nil {
- panic(err)
- }
-
- // The IV needs to be unique, but not secure. Therefore it's common to
- // include it at the beginning of the ciphertext.
- ciphertext := make([]byte, aes.BlockSize+len(plaintext))
- iv := ciphertext[:aes.BlockSize]
- if _, err := io.ReadFull(rand.Reader, iv); err != nil {
- panic(err)
- }
-
- stream := cipher.NewCFBEncrypter(block, iv)
- stream.XORKeyStream(ciphertext[aes.BlockSize:], plaintext)
-
- // It's important to remember that ciphertexts must be authenticated
- // (i.e. by using crypto/hmac) as well as being encrypted in order to
- // be secure.
-}
-
-func ExampleNewCTR() {
- key := []byte("example key 1234")
- plaintext := []byte("some plaintext")
-
- block, err := aes.NewCipher(key)
- if err != nil {
- panic(err)
- }
-
- // The IV needs to be unique, but not secure. Therefore it's common to
- // include it at the beginning of the ciphertext.
- ciphertext := make([]byte, aes.BlockSize+len(plaintext))
- iv := ciphertext[:aes.BlockSize]
- if _, err := io.ReadFull(rand.Reader, iv); err != nil {
- panic(err)
- }
-
- stream := cipher.NewCTR(block, iv)
- stream.XORKeyStream(ciphertext[aes.BlockSize:], plaintext)
-
- // It's important to remember that ciphertexts must be authenticated
- // (i.e. by using crypto/hmac) as well as being encrypted in order to
- // be secure.
-
- // CTR mode is the same for both encryption and decryption, so we can
- // also decrypt that ciphertext with NewCTR.
-
- plaintext2 := make([]byte, len(plaintext))
- stream = cipher.NewCTR(block, iv)
- stream.XORKeyStream(plaintext2, ciphertext[aes.BlockSize:])
-
- fmt.Printf("%s\n", plaintext2)
- // Output: some plaintext
-}
-
-func ExampleNewOFB() {
- key := []byte("example key 1234")
- plaintext := []byte("some plaintext")
-
- block, err := aes.NewCipher(key)
- if err != nil {
- panic(err)
- }
-
- // The IV needs to be unique, but not secure. Therefore it's common to
- // include it at the beginning of the ciphertext.
- ciphertext := make([]byte, aes.BlockSize+len(plaintext))
- iv := ciphertext[:aes.BlockSize]
- if _, err := io.ReadFull(rand.Reader, iv); err != nil {
- panic(err)
- }
-
- stream := cipher.NewOFB(block, iv)
- stream.XORKeyStream(ciphertext[aes.BlockSize:], plaintext)
-
- // It's important to remember that ciphertexts must be authenticated
- // (i.e. by using crypto/hmac) as well as being encrypted in order to
- // be secure.
-
- // OFB mode is the same for both encryption and decryption, so we can
- // also decrypt that ciphertext with NewOFB.
-
- plaintext2 := make([]byte, len(plaintext))
- stream = cipher.NewOFB(block, iv)
- stream.XORKeyStream(plaintext2, ciphertext[aes.BlockSize:])
-
- fmt.Printf("%s\n", plaintext2)
- // Output: some plaintext
-}
-
-func ExampleStreamReader() {
- key := []byte("example key 1234")
-
- inFile, err := os.Open("encrypted-file")
- if err != nil {
- panic(err)
- }
- defer inFile.Close()
-
- block, err := aes.NewCipher(key)
- if err != nil {
- panic(err)
- }
-
- // If the key is unique for each ciphertext, then it's ok to use a zero
- // IV.
- var iv [aes.BlockSize]byte
- stream := cipher.NewOFB(block, iv[:])
-
- outFile, err := os.OpenFile("decrypted-file", os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
- if err != nil {
- panic(err)
- }
- defer outFile.Close()
-
- reader := &cipher.StreamReader{S: stream, R: inFile}
- // Copy the input file to the output file, decrypting as we go.
- if _, err := io.Copy(outFile, reader); err != nil {
- panic(err)
- }
-
- // Note that this example is simplistic in that it omits any
- // authentication of the encrypted data. It you were actually to use
- // StreamReader in this manner, an attacker could flip arbitrary bits in
- // the output.
-}
-
-func ExampleStreamWriter() {
- key := []byte("example key 1234")
-
- inFile, err := os.Open("plaintext-file")
- if err != nil {
- panic(err)
- }
- defer inFile.Close()
-
- block, err := aes.NewCipher(key)
- if err != nil {
- panic(err)
- }
-
- // If the key is unique for each ciphertext, then it's ok to use a zero
- // IV.
- var iv [aes.BlockSize]byte
- stream := cipher.NewOFB(block, iv[:])
-
- outFile, err := os.OpenFile("encrypted-file", os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
- if err != nil {
- panic(err)
- }
- defer outFile.Close()
-
- writer := &cipher.StreamWriter{S: stream, W: outFile}
- // Copy the input file to the output file, encrypting as we go.
- if _, err := io.Copy(writer, inFile); err != nil {
- panic(err)
- }
-
- // Note that this example is simplistic in that it omits any
- // authentication of the encrypted data. It you were actually to use
- // StreamReader in this manner, an attacker could flip arbitrary bits in
- // the decrypted result.
-}
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