IDEA vector creation

This page documents the code that was used to generate the IDEA CBC, CFB, and OFB test vectors as well as the code used to verify them against another implementation. The vectors were generated using OpenSSL and verified with Botan.


cryptography was modified to support IDEA in CBC, CFB, and OFB modes. Then the following python script was run to generate the vector files.

import binascii

from cryptography.hazmat.backends.openssl.backend import backend
from cryptography.hazmat.primitives.ciphers import algorithms, base, modes

def encrypt(mode, key, iv, plaintext):
    cipher = base.Cipher(
    encryptor = cipher.encryptor()
    ct = encryptor.update(binascii.unhexlify(plaintext))
    ct += encryptor.finalize()
    return binascii.hexlify(ct)

def build_vectors(mode, filename):
    with open(filename, "r") as f:
        vector_file =

    count = 0
    output = []
    key = None
    iv = None
    plaintext = None
    for line in vector_file:
        line = line.strip()
        if line.startswith("KEY"):
            if count != 0:
                    "CIPHERTEXT = {0}".format(
                        encrypt(mode, key, iv, plaintext)
            output.append("\nCOUNT = {0}".format(count))
            count += 1
            name, key = line.split(" = ")
            output.append("KEY = {0}".format(key))
        elif line.startswith("IV"):
            name, iv = line.split(" = ")
            iv = iv[0:16]
            output.append("IV = {0}".format(iv))
        elif line.startswith("PLAINTEXT"):
            name, plaintext = line.split(" = ")
            output.append("PLAINTEXT = {0}".format(plaintext))

    output.append("CIPHERTEXT = {0}".format(encrypt(mode, key, iv, plaintext)))
    return "\n".join(output)

def write_file(data, filename):
    with open(filename, "w") as f:

CBC_PATH = "tests/hazmat/primitives/vectors/ciphers/AES/CBC/CBCMMT128.rsp"
write_file(build_vectors(modes.CBC, CBC_PATH), "idea-cbc.txt")
OFB_PATH = "tests/hazmat/primitives/vectors/ciphers/AES/OFB/OFBMMT128.rsp"
write_file(build_vectors(modes.OFB, OFB_PATH), "idea-ofb.txt")
CFB_PATH = "tests/hazmat/primitives/vectors/ciphers/AES/CFB/CFB128MMT128.rsp"
write_file(build_vectors(modes.CFB, CFB_PATH), "idea-cfb.txt")

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The following Python code was used to verify the vectors using the Botan project’s Python bindings.

import binascii

import botan

from tests.utils import load_nist_vectors


def encrypt(mode, key, iv, plaintext):
    encryptor = botan.Cipher(
        "IDEA/{0}/NoPadding".format(mode), "encrypt", binascii.unhexlify(key)

    cipher_text = encryptor.cipher(
        binascii.unhexlify(plaintext), binascii.unhexlify(iv)
    return binascii.hexlify(cipher_text)

def verify_vectors(mode, filename):
    with open(filename, "r") as f:
        vector_file =

    vectors = load_nist_vectors(vector_file)
    for vector in vectors:
        ct = encrypt(mode, vector["key"], vector["iv"], vector["plaintext"])
        assert ct == vector["ciphertext"]

cbc_path = "tests/hazmat/primitives/vectors/ciphers/IDEA/idea-cbc.txt"
verify_vectors("CBC", cbc_path)
ofb_path = "tests/hazmat/primitives/vectors/ciphers/IDEA/idea-ofb.txt"
verify_vectors("OFB", ofb_path)
cfb_path = "tests/hazmat/primitives/vectors/ciphers/IDEA/idea-cfb.txt"
verify_vectors("CFB", cfb_path)

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