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path: root/docs/development/custom-vectors/cast5/verify_cast5.go
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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, expected_ciphertext []byte)
}

type ofbVerifier struct{}

func (o ofbVerifier) validate(count string, key, iv, plaintext, expected_ciphertext []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, expected_ciphertext) {
        panic(fmt.Errorf("vector mismatch @ COUNT = %s:\n  %s != %s\n",
            count,
            hex.EncodeToString(expected_ciphertext),
            hex.EncodeToString(ciphertext)))
    }
}

type cbcVerifier struct{}

func (o cbcVerifier) validate(count string, key, iv, plaintext, expected_ciphertext []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, expected_ciphertext) {
        panic(fmt.Errorf("vector mismatch @ COUNT = %s:\n  %s != %s\n",
            count,
            hex.EncodeToString(expected_ciphertext),
            hex.EncodeToString(ciphertext)))
    }
}

type cfbVerifier struct{}

func (o cfbVerifier) validate(count string, key, iv, plaintext, expected_ciphertext []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, expected_ciphertext) {
        panic(fmt.Errorf("vector mismatch @ COUNT = %s:\n  %s != %s\n",
            count,
            hex.EncodeToString(expected_ciphertext),
            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{},
        "tests/hazmat/primitives/vectors/ciphers/CAST5/cast5-ofb.txt")
    fmt.Println("OFB OK.")
    validateVectors(cfbVerifier{},
        "tests/hazmat/primitives/vectors/ciphers/CAST5/cast5-cfb.txt")
    fmt.Println("CFB OK.")
    validateVectors(cbcVerifier{},
        "tests/hazmat/primitives/vectors/ciphers/CAST5/cast5-cbc.txt")
    fmt.Println("CBC OK.")
}