rsa v1

A Go package that provides a simple and secure interface for RSA key generation, management, and PEM encoding/decoding.

Repository

GitHub - metadiv-io/rsa: Go Package: RSA Key Pair GenerationGitHub

Installation

go get -u github.com/metadiv-io/rsa

Features

• Generate RSA key pairs with customizable bit sizes (minimum 1024 bits)

• Convenient 4096-bit key generation for long-term security

• PEM encoding/decoding for both public and private keys

• Type-safe key handling with separate PublicKey and PrivateKey types

Usage

Generating New Keys

// Generate a 4096-bit RSA key (recommended for long-term security)
privateKey := rsa.New4096RSAKey()

// Or generate a custom-sized key (minimum 1024 bits)
privateKey, err := rsa.NewRSAKey(2048)
if err != nil {
    // Handle error
}

Working with Keys

// Get the public key from a private key
publicKey := privateKey.PublicKey()

// Get key sizes
privateBits := privateKey.Size()  // Returns size in bits
publicBytes := publicKey.Size()   // Returns size in bytes

// Export keys as PEM strings
privatePEM := privateKey.Pem()
publicPEM := publicKey.Pem()

Loading Keys from PEM

// Load a private key from PEM
privateKey, err := rsa.NewPrivateKeyFromPem(pemString)
if err != nil {
    // Handle error
}

// Load a public key from PEM
publicKey, err := rsa.NewPublicKeyFromPem(pemString)
if err != nil {
    // Handle error
}

Error Handling

The package provides several error types for specific validation scenarios:

• ErrInvalidBitSize: Returned when the requested key size is not positive or not a multiple of 8

• ErrBitSizeTooSmall: Returned when the requested key size is less than 1024 bits

• ErrInvalidPEM: Returned when parsing an invalid PEM-encoded public key

• ErrNotRSAPublicKey: Returned when the parsed key is not an RSA public key

• ErrInvalidPrivateKeyPEM: Returned when parsing an invalid PEM-encoded private key

• ErrInvalidPrivateKey: Returned when the parsed private key is invalid

Security Recommendations

• Use 4096-bit keys (New4096RSAKey()) for long-term security beyond 2030

• Never share private keys or store them in plaintext

• Always use secure random number generation (handled automatically by this package)

• Keep your Go version updated to ensure you have the latest security patches