Rust AES CBC Decryption Failing – UnPad Error

I have written a Rust code to decrypt a string/s which is encrypted by a Java program. But I am seeing error when decrypting some strings.

In java program, it uses following functions to encrypt and decrypt.

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;


private static final byte[] IV_BYTES = new byte[16];
private static final IvParameterSpec IV_PARAMETER_SPEC = new IvParameterSpec(IV_BYTES);
protected static final String AES_CBC_PKCS5_PADDING = "AES/CBC/PKCS5Padding";

private static void initEncr() {
        try {
            cipherEnc.set(Cipher.getInstance(AES_CBC_PKCS5_PADDING));
            cipherEnc.get().init(Cipher.ENCRYPT_MODE, getDek(), IV_PARAMETER_SPEC);
        } catch (Throwable e) {
            throw new UDFException("Error initializing encrypt cipher: " + e.getMessage(), e);
        }
    }

private static void initDecr() {
        try {
            cipherDec.set(Cipher.getInstance(AES_CBC_PKCS5_PADDING));
            cipherDec.get().init(Cipher.DECRYPT_MODE, getDek(), IV_PARAMETER_SPEC);
        } catch (Throwable e) {
            throw new UDFException("Error initializing decrypt cipher: " + e.getMessage(), e);
        }
    }

I have two implementations of Rust code to decrypt a string

  1. Which is rust-crypto lib, which is deprecated and not maintained any more.
  2. aes and cbc lib from RustCrypto repo which is latest and actively maintained.

I am trying to decrypt below strings

string1:

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

string2

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

script1 was successful in decrypting the string, but script2 is failing with Unpad error. Error: called Result::unwrap() on an Err value: UnpadError at d_str.unwrap() line.

I want to use script2 as it is actively maintained and recommended.

Script1

dependencies:
base64 = "0.22.0"
rust-crypto = "^0.2"
extern crate crypto;

use crypto::{ buffer, aes, blockmodes };
use crypto::buffer::{ ReadBuffer, WriteBuffer, BufferResult };
use base64::prelude::*;
use crypto::symmetriccipher::Decryptor;


struct Decrypt {
    key: Vec<u8>,
    iv: [u8; 16],
}

impl Decrypt {

    fn new(key: &str) -> Self {
        Self {
            key: BASE64_STANDARD.decode(key).unwrap(),
            iv: [0; 16], // Default value for iv
        }
    }

    fn decryptor(&self) -> Box<dyn Decryptor>{
        let mut decryptor = aes::cbc_decryptor(
            aes::KeySize::KeySize256,
            self.key.as_slice(),
            &self.iv,
            blockmodes::PkcsPadding);
        decryptor
    }

    fn decrypt(&self, encrypted_data: &str) -> String {

        let encrypted_data = BASE64_STANDARD.decode(encrypted_data).unwrap();

        let mut decryptor = self.decryptor();

        let mut final_result = Vec::<u8>::new();
        let mut read_buffer = buffer::RefReadBuffer::new(encrypted_data.as_slice());
        let mut buffer = [0; 4096];
        let mut write_buffer = buffer::RefWriteBuffer::new(&mut buffer);

        loop {
            let result = decryptor.decrypt(&mut read_buffer, &mut write_buffer, true).unwrap();
            final_result.extend(write_buffer.take_read_buffer().take_remaining().iter().map(|&i| i));
            match result {
                BufferResult::BufferUnderflow => break,
                BufferResult::BufferOverflow => { }
            }
        }

        String::from_utf8(final_result).unwrap()
    }
}

Script2

dependencies:
aes = "0.8.4"
base64 = "0.22.1"
cbc = "0.1.2"
use aes::Aes256;
use aes::cipher::{block_padding::Pkcs7, BlockDecryptMut, KeyIvInit};

type Aes256CbcDec = cbc::Decryptor<aes::Aes256>;

use base64::prelude::*;
use cbc::Decryptor;



struct Decrypt {
    key: Vec<u8>,
    iv: [u8; 16],
}

impl Decrypt {

    fn new(key: &str) -> Self {
        Self {
            key: BASE64_STANDARD.decode(key).unwrap(),
            iv: [0; 16], // Default value for iv
        }
    }

    fn decryptor(&self) -> Decryptor<Aes256>{
        let decryptor = Aes256CbcDec::new_from_slices(
            self.key.as_slice(),
            &self.iv,
        ).unwrap();
        decryptor
    }

    fn decrypt(&self, encrypted_data: &str) -> String {

        let encrypted_data = BASE64_STANDARD.decode(encrypted_data).unwrap();

        let mut decryptor = self.decryptor();
        let mut buf = [0u8; 4096];
        let d_str = decryptor.decrypt_padded_b2b_mut::<Pkcs7>(&encrypted_data,
                                                              &mut buf);
        let  res = d_str.unwrap().to_vec();

        String::from_utf8(res).unwrap()
    }
}

Trang chủ Giới thiệu Sinh nhật bé trai Sinh nhật bé gái Tổ chức sự kiện Biểu diễn giải trí Dịch vụ khác Trang trí tiệc cưới Tổ chức khai trương Tư vấn dịch vụ Thư viện ảnh Tin tức - sự kiện Liên hệ Chú hề sinh nhật Trang trí YEAR END PARTY công ty Trang trí tất niên cuối năm Trang trí tất niên xu hướng mới nhất Trang trí sinh nhật bé trai Hải Đăng Trang trí sinh nhật bé Khánh Vân Trang trí sinh nhật Bích Ngân Trang trí sinh nhật bé Thanh Trang Thuê ông già Noel phát quà Biểu diễn xiếc khỉ Xiếc quay đĩa Dịch vụ tổ chức sự kiện 5 sao Thông tin về chúng tôi Dịch vụ sinh nhật bé trai Dịch vụ sinh nhật bé gái Sự kiện trọn gói Các tiết mục giải trí Dịch vụ bổ trợ Tiệc cưới sang trọng Dịch vụ khai trương Tư vấn tổ chức sự kiện Hình ảnh sự kiện Cập nhật tin tức Liên hệ ngay Thuê chú hề chuyên nghiệp Tiệc tất niên cho công ty Trang trí tiệc cuối năm Tiệc tất niên độc đáo Sinh nhật bé Hải Đăng Sinh nhật đáng yêu bé Khánh Vân Sinh nhật sang trọng Bích Ngân Tiệc sinh nhật bé Thanh Trang Dịch vụ ông già Noel Xiếc thú vui nhộn Biểu diễn xiếc quay đĩa Dịch vụ tổ chức tiệc uy tín Khám phá dịch vụ của chúng tôi Tiệc sinh nhật cho bé trai Trang trí tiệc cho bé gái Gói sự kiện chuyên nghiệp Chương trình giải trí hấp dẫn Dịch vụ hỗ trợ sự kiện Trang trí tiệc cưới đẹp Khởi đầu thành công với khai trương Chuyên gia tư vấn sự kiện Xem ảnh các sự kiện đẹp Tin mới về sự kiện Kết nối với đội ngũ chuyên gia Chú hề vui nhộn cho tiệc sinh nhật Ý tưởng tiệc cuối năm Tất niên độc đáo Trang trí tiệc hiện đại Tổ chức sinh nhật cho Hải Đăng Sinh nhật độc quyền Khánh Vân Phong cách tiệc Bích Ngân Trang trí tiệc bé Thanh Trang Thuê dịch vụ ông già Noel chuyên nghiệp Xem xiếc khỉ đặc sắc Xiếc quay đĩa thú vị
Trang chủ Giới thiệu Sinh nhật bé trai Sinh nhật bé gái Tổ chức sự kiện Biểu diễn giải trí Dịch vụ khác Trang trí tiệc cưới Tổ chức khai trương Tư vấn dịch vụ Thư viện ảnh Tin tức - sự kiện Liên hệ Chú hề sinh nhật Trang trí YEAR END PARTY công ty Trang trí tất niên cuối năm Trang trí tất niên xu hướng mới nhất Trang trí sinh nhật bé trai Hải Đăng Trang trí sinh nhật bé Khánh Vân Trang trí sinh nhật Bích Ngân Trang trí sinh nhật bé Thanh Trang Thuê ông già Noel phát quà Biểu diễn xiếc khỉ Xiếc quay đĩa
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