tweetnacl

This egg is a CHICKEN wrapper around TweetNaCl. The C source code for TweetNaCl is included in the egg.

Usage

 (import tweetnacl)

Asymmetric Algorithms

[constant] asymmetric-box-primitive

A string that briefly describes the algorithm combination used to implement asymmetric cryptographic boxes.

[constant] asymmetric-box-publickeybytes

The size of public keys for asymmetric cryptographic boxes in bytes.

[constant] asymmetric-box-secretkeybytes

The size of private keys for asymmetric cryptographic boxes in bytes.

[constant] asymmetric-box-noncebytes

The size of nonces for asymmetric cryptographic boxes in bytes.

[procedure] (make-asymmetric-box-keypair [entropy-port (current-entropy-port)])

Generate a new keypair for asymmetric boxing. Reads data from entropy-port. Returns two blobs representing the new public and secret key.

[procedure] ((asymmetric-box pk sk) m n)

Encrypt and authenticate a message m from secret key sk to public key pk using nonce n for algorithm randomization. The plaintext m and the returned ciphertext are represented as strings, the nonce n is represented as a u8vector.

[procedure] ((asymmetric-unbox pk sk) c n)

Decrypt and verify a message c from the public key pk to the secret key sk using nonce n for algorithm randomization. The ciphertext c and the returned plaintext are represented as strings, the nonce n is represented as a u8vector. If the authenticity of the message cannot be verified the procedure returns #f instead of a string.

[constant] asymmetric-sign-primitive

A string that briefly describes the algorithm combination used to implement asymmetric cryptographic signatures.

[constant] asymmetric-sign-publickeybytes

The size of public keys for asymmetric cryptographic signatures in bytes.

[constant] asymmetric-sign-secretkeybytes

The size of private keys for asymmetric cryptographic signatures in bytes.

[procedure] (make-asymmetric-sign-keypair [entropy-port (current-entropy-port)])

Generate a new keypair for asymmetric signing. Reads data from entropy-port. Returns two blobs representing the new public and secret key.

[procedure] ((asymmetric-sign sk) m)

Sign a message m from secret key sk to the general public. The plaintext m and the returned signature message combination are represented as strings.

[procedure] ((asymmetric-verify pk) sm)

Decrypt and verify a message sm from the public key pk to the general public. The signature message combination sm and the returned plaintext are represented as strings. If the authenticity of the message cannot be verified the procedure returns #f instead of a string.

[constant] scalarmult-primitive

A string that briefly describes the scalar multiplication algorithm.

[constant] scalarmult-pointbytes

The size of field elements in bytes.

[constant] scalarmult-scalarbytes

The size of scalar values in bytes.

[procedure] (scalarmult* n p)

Multiplies the field element p by the scalar n and returns a new field element.

Warning: This is a low-level primitive that should be used with care. Key agreement schemes can be implemented using this function, but the result does have inherent algebraic structure and must be passed through a hash function before it can be used safely as a cryptographic key.

Symmetric Algorithms

[constant] symmetric-box-primitive

A string that briefly describes the algorithm combination used to implement symmetric cryptographic boxes.

[constant] symmetric-box-keybytes

The size of shared keys for symmetric cryptographic boxes in bytes.

[constant] symmetric-box-noncebytes

The size of nonces for symmetric cryptographic boxes in bytes.

[procedure] (make-symmetric-box-key [entropy-port (current-entropy-port)])

Generate a new key for symmetric boxing. Reads data from entropy-port. Returns a blob representing the new shared key.

[procedure] (derive-symmetric-box-key pk sk)

Derive a new key for symmetric boxing from secret key sk to public key pk. The results of

(symmetric-box (derive-symmetric-box-key pk sk))

and

(asymmetric-box pk sk)

are equivalent. The same holds for the corresponding unbox calls.

[procedure] ((symmetric-box k) m n)

Encrypt and authenticate a message m using the shared key k and nonce n for algorithm randomization. The plaintext m and the returned ciphertext are represented as strings, the nonce n is represented as a u8vector.

[procedure] ((symmetric-unbox k) c n)

Decrypt and verify a message c using the shared key k and nonce n for algorithm randomization. The ciphertext c and the returned plaintext are represented as strings, the nonce n is represented as a u8vector. If the authenticity of the message cannot be verified the procedure returns #f instead of a string.

[constant] symmetric-sign-primitive

A string that briefly describes the algorithm combination used to implement symmetric cryptographic one-time signatures.

[constant] symmetric-sign-keybytes

The size of shared keys for symmetric cryptographic one-time signatures in bytes.

[procedure] (make-symmetric-sign-key [entropy-port (current-entropy-port)])

Generate a new key for symmetric signing. Reads data from entropy-port. Returns a blob representing the new shared key.

[procedure] ((symmetric-sign k) m #!key tag-only?)

Sign a message m using the shared key k. The plaintext m and the returned signature message combination are represented as strings. If tag-only? is given and not #f, the procedure returns only the message authentication tag as a string rather than a combination of authentication tag and message.

[procedure] ((symmetric-verify k) sm #!optional m)

Decrypt and verify a message sm using the shared key k. The signature message combination sm and the returned plaintext are represented as strings. If the authenticity of the message cannot be verified the procedure returns #f instead of a string. If m is given and not #f it must be a string containing the plaintext of the message and sm is expected to only contain the message authentication tag in that case.

Pseudo-Random Streams

[constant] random-stream-primitive

A string that briefly describes the algorithm combination used to implement pseudo-random streams.

[constant] random-stream-keybytes

The size of shared keys for pseudo-random streams in bytes.

[constant] random-stream-noncebytes

The size of nonces for pseudo-random streams in bytes.

[procedure] (make-random-stream-key [entropy-port (current-entropy-port)])

Generate a new key for pseudo-random streams. Reads data from entropy-port. Returns a blob representing the new shared key.

[procedure] (derive-random-stream-key pk sk)

Derive a new key for pseudo-random streams from secret key sk to public key pk.

[procedure] (open-random-stream k n #!optional [limit (expt 2 30)])

Open a stream of pseudo-random bytes using the shared key k and nonce n for algorithm randomization. The stream ends after limit bytes, unless limit is #f or infinity.

[procedure] (stream-xor! buffer #!optional [stream (current-input-port)])

Destructively xors the contents of the string buffer with bytes read from stream. Returns buffer.

[procedure] (stream-xor buffer #!optional [stream (current-input-port)])

Xors the contents of the string buffer with bytes read from stream. Returns a new string holding the result.

Miscellaneous

[constant] hash-primitive

A string that briefly describes the message digest algorithm.

[constant] hash-bytes

The size of message digests in bytes.

[procedure] (hash m)

Hashes the string m into a message digest. Returns the binary digest as a string.

[parameter] current-entropy-port

An input port connected to an entropy source for key generation.

When compiled on a unix system, this parameter is by default bound to the result of (open-input-file "/dev/random"). When compiled on a windows system, the default value of the parameter is a custom input port that returns bytes produced by RtlGenRandom. On other systems the default value of the parameter will be #f and you will have to set it explicitly before key generation functions can be used.

To speed up key generation it can be useful to set current-entropy-port to a pseudo-random stream only seeded initially from the system entropy source:

 (current-entropy-port (open-random-stream (make-random-stream-key) (make-u8vector random-stream-noncebytes 0)))

Author

Repository

Description

Usage

Asymmetric Algorithms

Symmetric Algorithms

Pseudo-Random Streams

Miscellaneous