This PHP extension provides the primitives required to implement and use the IETF Encrypted Content-Encoding draft in PHP.

https://tools.ietf.org/html/draft-thomson-http-encryption

The GMP extension can be used for more convenience in converting to and from numbers of arbitrary length coming from binary strings.

This extension is not meant to be used for production usage.

The following functions are available as part of this extension.

• P-256 Functions
  • ece_p256_generate()
  • [ece_p256_import(string $public[, string $private])] (#resource-ece_p256_importstring-public-string-private)
  • ece_p256_export(resource $key)
  • [ece_p256_compute_key(resource $local_key, resource $peer_key)] (#string-ece_p256_compute_keyresource-local_key-resource-peer_key)
  • ece_p256_free(resource $key)
• AES-GCM Functions
  • [ece_aesgcm128_encrypt(string $plaintext, string $key, string $nonce)] (#string-ece_aesgcm128_encryptstring-plaintext-string-key-string-nonce)
  • [ece_aesgcm128_decrypt(string $ciphertext, string $key, string $nonce)] (#string-ece_aesgcm128_decryptstring-ciphertext-string-key-string-nonce)
• Miscellaneous
  • ece_random_bytes(int $length)

Generates and returns a new P-256 key pair.

Returns NULL and displays an error if the pair could not be generated for any reason.

Imports $public (and optionally $private) to a new P-256 key pair. Returns NULL and displays an error if the pair could not be imported for any reason.

The $public key must be given as a string holding the raw bytes of a P-256 public key in uncompressed form per SEC1 2.3.3.

The $private key, when given, must be a string holding the raw bytes of the 32-byte long field element representing the private value. It will be verified that the $public and $private keys are indeed a pair.

Exports the $key to an array with two keys: public set to a string holding the raw bytes of the P-256 public key in $key in uncompressed form per SEC1 2.3.3, and private set to a string holding the raw bytes of the private value.

If the $key does not have a private value, the private key in the returned array will instead be set to NULL.

Computes the shared key between the $local_key and the $peer_key, returns the key as a string holding the 32-byte long shared secret.

The $local_key must have both the public and private key set. Only the public key of the $peer_key is required.

Frees the P-256 key in $key.

Encrypts $plaintext using AEAD_AES_GCM_128 using $key as the encryption key and $nonce as the IV.

The $key must be passed as a binary string that is exactly 128 bits (16 bytes) in length. The $nonce must be passed as a binary string that is exactly 96 bits (12 bytes) in length.

An authentication tag of 128 bits (16 bytes) will be prepended to the returned string. The returned string wil be in binary format.

Decrypts $ciphertext using AEAD_AES_GCM_128 using $key as the encryption key and $nonce as the IV.

The $key must be passed as a binary string that is exactly 128 bits (16 bytes) in length. The $nonce must be passed as a binary string that is exactly 96 bits (12 bytes) in length.

An authentication tag of 128 bits (16 bytes) is expected to be included at the beginning of $ciphertext. Omission of the authentication tag is considered to be a fatal error.

The returned string wil be in binary format.

Creates and returns a string with $length cryptographically secure random bytes. Will fail and display an error if there is not sufficient entropy available.