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package main
import (
"bufio"
"bytes"
"code.google.com/p/go.crypto/cast5"
"crypto/cipher"
"encoding/hex"
"fmt"
"os"
"strings"
)
func unhexlify(s string) []byte {
bytes, err := hex.DecodeString(s)
if err != nil {
panic(err)
}
return bytes
}
type vectorArgs struct {
count string
key string
iv string
plaintext string
ciphertext string
}
type vectorVerifier interface {
validate(count string, key, iv, plaintext, expectedCiphertext []byte)
}
type ofbVerifier struct{}
func (o ofbVerifier) validate(count string, key, iv, plaintext, expectedCiphertext []byte) {
block, err := cast5.NewCipher(key)
if err != nil {
panic(err)
}
ciphertext := make([]byte, len(plaintext))
stream := cipher.NewOFB(block, iv)
stream.XORKeyStream(ciphertext, plaintext)
if !bytes.Equal(ciphertext, expectedCiphertext) {
panic(fmt.Errorf("vector mismatch @ COUNT = %s:\n %s != %s\n",
count,
hex.EncodeToString(expectedCiphertext),
hex.EncodeToString(ciphertext)))
}
}
type cbcVerifier struct{}
func (o cbcVerifier) validate(count string, key, iv, plaintext, expectedCiphertext []byte) {
block, err := cast5.NewCipher(key)
if err != nil {
panic(err)
}
ciphertext := make([]byte, len(plaintext))
mode := cipher.NewCBCEncrypter(block, iv)
mode.CryptBlocks(ciphertext, plaintext)
if !bytes.Equal(ciphertext, expectedCiphertext) {
panic(fmt.Errorf("vector mismatch @ COUNT = %s:\n %s != %s\n",
count,
hex.EncodeToString(expectedCiphertext),
hex.EncodeToString(ciphertext)))
}
}
type cfbVerifier struct{}
func (o cfbVerifier) validate(count string, key, iv, plaintext, expectedCiphertext []byte) {
block, err := cast5.NewCipher(key)
if err != nil {
panic(err)
}
ciphertext := make([]byte, len(plaintext))
stream := cipher.NewCFBEncrypter(block, iv)
stream.XORKeyStream(ciphertext, plaintext)
if !bytes.Equal(ciphertext, expectedCiphertext) {
panic(fmt.Errorf("vector mismatch @ COUNT = %s:\n %s != %s\n",
count,
hex.EncodeToString(expectedCiphertext),
hex.EncodeToString(ciphertext)))
}
}
type ctrVerifier struct{}
func (o ctrVerifier) validate(count string, key, iv, plaintext, expectedCiphertext []byte) {
block, err := cast5.NewCipher(key)
if err != nil {
panic(err)
}
ciphertext := make([]byte, len(plaintext))
stream := cipher.NewCTR(block, iv)
stream.XORKeyStream(ciphertext, plaintext)
if !bytes.Equal(ciphertext, expectedCiphertext) {
panic(fmt.Errorf("vector mismatch @ COUNT = %s:\n %s != %s\n",
count,
hex.EncodeToString(expectedCiphertext),
hex.EncodeToString(ciphertext)))
}
}
func validateVectors(verifier vectorVerifier, filename string) {
vectors, err := os.Open(filename)
if err != nil {
panic(err)
}
defer vectors.Close()
var segments []string
var vector *vectorArgs
scanner := bufio.NewScanner(vectors)
for scanner.Scan() {
segments = strings.Split(scanner.Text(), " = ")
switch {
case strings.ToUpper(segments[0]) == "COUNT":
if vector != nil {
verifier.validate(vector.count,
unhexlify(vector.key),
unhexlify(vector.iv),
unhexlify(vector.plaintext),
unhexlify(vector.ciphertext))
}
vector = &vectorArgs{count: segments[1]}
case strings.ToUpper(segments[0]) == "IV":
vector.iv = segments[1][:16]
case strings.ToUpper(segments[0]) == "KEY":
vector.key = segments[1]
case strings.ToUpper(segments[0]) == "PLAINTEXT":
vector.plaintext = segments[1]
case strings.ToUpper(segments[0]) == "CIPHERTEXT":
vector.ciphertext = segments[1]
}
}
}
func main() {
validateVectors(ofbVerifier{},
"vectors/cryptography_vectors/ciphers/CAST5/cast5-ofb.txt")
fmt.Println("OFB OK.")
validateVectors(cfbVerifier{},
"vectors/cryptography_vectors/ciphers/CAST5/cast5-cfb.txt")
fmt.Println("CFB OK.")
validateVectors(cbcVerifier{},
"vectors/cryptography_vectors/ciphers/CAST5/cast5-cbc.txt")
fmt.Println("CBC OK.")
validateVectors(ctrVerifier{},
"vectors/cryptography_vectors/ciphers/CAST5/cast5-ctr.txt")
fmt.Println("CTR OK.")
}
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