You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: crypto.rs
    path of file: ./repos/hyperswitch/crates/common_utils/src
    
    the code of the file until where you have to start completion: //! Utilities for cryptographic algorithms
use std::ops::Deref;

use error_stack::{IntoReport, ResultExt};
use masking::{ExposeInterface, Secret};
use md5;
use ring::{
    aead::{self, BoundKey, OpeningKey, SealingKey, UnboundKey},
    hmac,
};

use crate::{
    errors::{self, CustomResult},
    pii::{self, EncryptionStratergy},
};

#[derive(Clone, Debug)]
struct NonceSequence(u128);

impl NonceSequence {
    /// Byte index at which sequence number starts in a 16-byte (128-bit) sequence.
    /// This byte index considers the big endian order used while encoding and decoding the nonce
    /// to/from a 128-bit unsigned 
    
    fn test_md5_verify_signature() {
        let right_signature =
            hex::decode("c3fcd3d76192e4007dfb496cca67e13b").expect("signature decoding");
        let wrong_signature =
            hex::decode("d5550730377011948f12cc28889bee590d2a5434d6f54b87562f2dbc2657823f")
                .expect("Wrong signature decoding");
        let secret = "".as_bytes();
        let data = "abcdefghijklmnopqrstuvwxyz".as_bytes();

        let right_verified = super::Md5
            .verify_signature(secret, &right_signature, data)
            .expect("Right signature verification result");

        assert!(right_verified);

        let wrong_verified = super::Md5
            .verify_signature(secret, &wrong_signature, data)
            .expect("Wrong signature verification result");

        assert!(!wrong_verified);
    }