相当于java解密代码的openssl（shell脚本）

Question

Need help with openssl, What would be the openssl equivalent of the below java method?

private static String decryptString(String value, String myKey) {

    MessageDigest sha = null;
    SecretKeySpec secretKey = null;
    try {
        byte[] key = myKey.getBytes("UTF-8");
        sha = MessageDigest.getInstance("SHA-1");
        key = sha.digest(key);
        key = Arrays.copyOf(key, 16); // use only first 128 bit
        secretKey = new SecretKeySpec(key, "AES");
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5PADDING");
        cipher.init(Cipher.DECRYPT_MODE, secretKey);
        return (new String(cipher.doFinal(Base64.decodeBase64(value))));
    } catch (Exception e) {
        System.out.println("Error while decrypting: " + e.toString());
    }
    return null;
}

Answer 1

The function is digesting a string (myKey) using SHA-1 and then using the first 16 bytes of the resulting digest as the key for an AES128-ECB decryption operation. Before decryption, the ciphertext is first base64 decoded.

To digest a string using SHA-1 use the code here: https://wiki.openssl.org/index.php/EVP_Message_Digests

That code actually uses SHA-256. To make it do SHA-1 instead replace the instance of EVP_sha256() with EVP_sha1() . The first 16 bytes of the result is your "key".

Next the input "value" is base64 decoded. There is some sample code to do that with OpenSSL here:

http://www.ioncannon.net/programming/122/howto-base64-decode-with-cc-and-openssl/

Finally, to do the AES-ECB decryption operation use the code here:

https://wiki.openssl.org/index.php/EVP_Symmetric_Encryption_and_Decryption#Decrypting_the_Message

That code is using AES256-CBC. To make it do AES128-ECB instead replace the instance of EVP_aes_256_cbc() with EVP_aes_128_ecb() . The key argument is as you calculated above. The iv argument is just NULL for ECB. The ciphertext is the base64 decoded data that you calculated above. Note that the "PKCS5PADDING" part of the Java code is the default in OpenSSL anyway, so nothing special needs to be done for that.

The plaintext that has been output from the decryption operation is the return value from your Java function.