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Version: 0.1.22

PKC utility

Public key cryptography CLI (RSA encrypt/decrypt, sign/verify).

Operations: encrypt, decrypt, sign, verify, genkey. Algorithm: rsa. Parameters: operation, algorithm, then key/data as needed. Options: -k <bits> key size (1024,2048,3072,4096), -h <algo> hash (md5,sha1,sha256), -d debug, -x input as hex, -v version.

This utility provides command-line access to public key cryptography operations, currently supporting RSA.

Building​

The PKC utility is built as part of the main project:

cd build
ninja pkc

Or build all applications:

ninja

Usage​

General Syntax​

pkc [operation] [algorithm] [options] [data...]

Operations​

  • encrypt - Encrypt data using public key
  • decrypt - Decrypt data using private key
  • sign - Sign data using private key
  • verify - Verify signature using public key
  • genkey - Generate RSA key pair

Algorithms​

  • rsa - RSA (Rivest-Shamir-Adleman) public key cryptography

Options​

  • -k <size> - Key size in bits (1024, 2048, 3072, 4096). Default: 2048
  • -h <algo> - Hash algorithm for signatures (md5, sha1, sha256). Default: sha256
  • -d - Enable debug mode
  • -x - Interpret input data as hexadecimal string
  • -v - Version information
  • --help or -h - Show help message

Examples​

Generate RSA Key Pair​

pkc genkey rsa -k 2048

This generates a 2048-bit RSA key pair and displays the public and private key components.

Encrypt Data​

pkc encrypt rsa "Hello World"

Encrypts the message "Hello World" using a newly generated RSA key pair. The output includes:

  • The ciphertext (hexadecimal)
  • The public key (modulus n and exponent e) for decryption

Sign Data​

pkc sign rsa "Message to sign" -h sha256

Signs the message using a newly generated RSA key pair with SHA-256 hashing. The output includes:

  • The signature (hexadecimal)
  • The public key (modulus n and exponent e) for verification

Decrypt Data​

pkc decrypt rsa <hex_ciphertext>

Note: Decryption with external keys is not yet fully implemented. The current implementation generates a new key pair for each operation.

Verify Signature​

pkc verify rsa "Message" <hex_signature>

Note: Verification with external keys is not yet fully implemented. The current implementation requires the public key to be provided separately.

Key Sizes​

Supported RSA key sizes:

  • 1024 bits (not recommended for production)
  • 2048 bits (recommended minimum)
  • 3072 bits
  • 4096 bits (high security)

Hash Algorithms for Signatures​

Supported hash algorithms:

  • md5 - MD5 (not recommended for new applications)
  • sha1 - SHA-1 (deprecated, not recommended)
  • sha256 - SHA-256 (recommended)

Output Format​

All binary data (ciphertext, signatures, keys) is displayed in hexadecimal format.

Security Notes​

  1. Key Generation: Key generation uses random number generation. For production use, ensure a cryptographically secure random number generator.

  2. Key Storage: The current implementation does not persist keys. Keys are generated for each operation. In production, keys should be securely stored and loaded.

  3. Key Sizes: Use at least 2048-bit keys for RSA. 1024-bit keys are considered insecure.

  4. Hash Algorithms: Use SHA-256 or stronger for signatures. MD5 and SHA-1 are deprecated.

  5. Key Management: Private keys should never be transmitted or stored insecurely.

Future Enhancements​

  • Key import/export functionality
  • Support for loading keys from files
  • Support for ECC, ECDSA, and ECDH algorithms
  • Key persistence and management
  • More padding schemes (OAEP, PSS)

Examples​

pkc encrypt rsa "Hello World" pkc decrypt rsa <hex_ciphertext> pkc sign rsa "Message to sign" pkc verify rsa "Message" <hex_signature> pkc genkey rsa -k 2048 pkc -h