zena:crypto
zena
import {…} from 'zena:crypto';
Cryptography: SHA-256, HMAC-SHA256, HKDF-SHA256, and ECDSA on P-256 and secp256k1. Pure Zena.
zena
import {hmacSha256, p256, sha256Hex} from 'zena:crypto';
let digest = sha256Hex(bytes);
let mac = hmacSha256(key, message);
let signature = p256.sign(privateKey, message);
Classes
HkdfError
zena
class HkdfError extends Error
An HKDF output length outside what RFC 5869 allows.
Constructors
zena
new(message: String)
EcdsaError
zena
class EcdsaError extends Error
A private key out of range, a malformed public key, or a digest that is not 32 bytes.
Constructors
zena
new(message: String)
EcdsaCurve
zena
final class EcdsaCurve
A curve to sign and verify on: p256 or secp256k1.
Constructors
zena
new(curve: Curve)
Properties
zena
name: String { get; }
P-256 or secp256k1.
Methods
zena
publicKey(privateKey: FixedArray<u8>, compressed: boolean = true): FixedArray<u8>
The SEC1 encoding of the public key for privateKey. Throws an
EcdsaError when the private key is not 32 bytes or not from 1 to
n - 1, as sign does.
zena
compressPublicKey(key: FixedArray<u8>): FixedArray<u8>
The 33-byte compressed form of a SEC1 public key in either form.
Throws an EcdsaError when key is malformed or not on the curve.
zena
decompressPublicKey(key: FixedArray<u8>): FixedArray<u8>
The 65-byte uncompressed form of a SEC1 public key, as compressPublicKey takes it.
zena
sign(privateKey: FixedArray<u8>, message: FixedArray<u8>): FixedArray<u8>
The low-S signature of the SHA-256 hash of message.
zena
signDigest(privateKey: FixedArray<u8>, digest: FixedArray<u8>): FixedArray<u8>
The low-S signature of a 32-byte SHA-256 digest, with the nonce derived from the key and the digest as RFC 6979 section 3.2 describes.
zena
signatureFromDer(der: FixedArray<u8>): FixedArray<u8>
The 64-byte low-S signature an ASN.1 DER ECDSA-Sig-Value holds:
SEQUENCE { r INTEGER, s INTEGER }, as X.509, PKCS #11 and key
management services such as Cloud KMS write signatures. A high-S
signature, which they may give, is turned into its low-S twin, which
signs the same message. Throws an EcdsaError for anything else, or
an r or s that is 0 or not below the group order.
zena
verify(key: FixedArray<u8>, message: FixedArray<u8>, signature: FixedArray<u8>, allowHighS: boolean = false): boolean
Whether signature is a valid signature of the SHA-256 hash of
message under the SEC1 public key key. False for a malformed
signature or key, a key not on the curve, and, unless allowHighS, a
high-S signature.
zena
verifyDigest(key: FixedArray<u8>, digest: FixedArray<u8>, signature: FixedArray<u8>, allowHighS: boolean = false): boolean
verify for a SHA-256 digest of the message. Throws an EcdsaError
when digest is not 32 bytes.
Functions
sha256
zena
function sha256(data: FixedArray<u8>): FixedArray<u8>
The 32-byte SHA-256 digest of data.
toHex
zena
function toHex(bytes: FixedArray<u8>): String
bytes as lowercase hex; the same as hex.encode from zena:encoding.
sha256Hex
zena
function sha256Hex(data: FixedArray<u8>): String
The digest as a lowercase hex string.
sha256HexOfString
zena
function sha256HexOfString(s: String): String
The digest of a string's bytes as a lowercase hex string.
hmacSha256
zena
function hmacSha256(key: FixedArray<u8>, message: FixedArray<u8>): FixedArray<u8>
The HMAC-SHA256 of message under key.
constantTimeEquals
zena
function constantTimeEquals(a: FixedArray<u8>, b: FixedArray<u8>): boolean
Whether a and b hold the same bytes, taking as long whichever byte
differs, so that comparing a MAC or a secret's hash with the expected
one does not show, by its timing, how much of it was right. Only the
lengths, which are not secret, end it early.
hkdfExtract
zena
function hkdfExtract(salt: FixedArray<u8>, ikm: FixedArray<u8>): FixedArray<u8>
HKDF's extract step: a 32-byte pseudorandom key from input keying material and an optional salt. RFC 5869 says an empty salt stands for 32 zero bytes; HMAC pads its key with zeros to a block either way, so passing the empty salt through gives the same result.
hkdfExpand
zena
function hkdfExpand(prk: FixedArray<u8>, info: FixedArray<u8>, length: i32): FixedArray<u8>
HKDF's expand step: length bytes from a pseudorandom key and context
info. length is at most 255 * 32 bytes.
hkdf
zena
function hkdf(salt: FixedArray<u8>, ikm: FixedArray<u8>, info: FixedArray<u8>, length: i32): FixedArray<u8>
HKDF-SHA256: extract, then expand to length bytes.
Variables
p256
zena
let p256: EcdsaCurve
NIST P-256, also called secp256r1 and prime256v1.
secp256k1
zena
let secp256k1: EcdsaCurve
secp256k1, the curve Bitcoin uses.