tutil

tutil is a compact Go utility package for sortable identifiers, hashing and HMAC helpers, interoperability-oriented AES/RSA/SM2/SM4 helpers, non-cryptographic random values, and MySQL DSN password escaping.

Installation

go get github.com/choveylee/tutil

Requires Go 1.25 or later.

Quick start

package main

import (
	"fmt"

	"github.com/choveylee/tutil"
)

func main() {
	u := tutil.NewUid()
	fmt.Println(u.String())

	oid := tutil.NewOid()
	fmt.Println(oid.Hex())
}

Complete API reference: pkg.go.dev/github.com/choveylee/tutil.

Features

• Identifiers - Uid (ULID) and Oid (12-byte BSON ObjectID), including database/sql scanning, driver.Valuer, string parsing, and GORM schema type hints.
• Hashing and HMAC - MD5, SHA-1, HMAC-MD5, HMAC-SHA1, and HMAC-SHA256 helpers. MD5 and SHA-1 are retained for compatibility scenarios.
• Symmetric cryptography - AES and SM4 ECB/CBC helpers with PKCS #7 or zero padding for interoperability with existing systems.
• Asymmetric cryptography - RSA PEM key generation, RSAES-OAEP encryption/decryption, and SHA-256 signing/verification, plus SM2 encryption/decryption via gmsm.
• Random values - math/rand-based integers and strings intended only for non-security use.
• MySQL DSN escaping - MysqlDsnEncode escapes the password portion of simple user:password@host DSNs.

Direct dependencies

Module	Role
github.com/oklog/ulid/v2	ULID generation and parsing
go.mongodb.org/mongo-driver/v2/bson	ObjectID backing type
github.com/tjfoc/gmsm	SM2 / SM4

API Notes

• AesEncrypt and AesDecrypt operate on exactly one AES block. Use the explicit ECB/CBC helpers for longer inputs.
• AES-CBC uses the first key block as the IV when iv is empty. This behavior is retained for legacy compatibility; new code should supply a fresh random IV.
• Zero padding is lossy when plaintext can end with zero bytes.
• RsaEncrypt and RsaDecrypt use RSAES-OAEP with SHA-256.
• ResetRsaKeyType configures the process-wide default PEM encodings used by RSAKeyGenerator and RSAKeyGeneratorTo. RSA parsing helpers detect key formats from the PEM block type.
• RSAKeyGeneratorTo accepts 1024-bit keys for legacy interoperability; new deployments should use at least 2048 bits.
• MysqlDsnEncode is intentionally narrow in scope. Use a DSN parser for URL-style or driver-specific connection strings.

Security

For new designs, prefer authenticated encryption such as AES-GCM over raw ECB/CBC helpers. MD5, SHA-1, RSASSA-PKCS1-v1_5 signatures, 1024-bit RSA keys, and math/rand helpers are retained for compatibility or non-security use cases.

Contributing

Issues and pull requests are welcome. Before submitting changes, run:

go test ./...
go vet ./...