Key and text helpers

Named exports are available from the package root in both runtimes:

import {
  isValidRSAPublicKey, isValidRSAPrivateKey,
  isValidPEMPublicKey, isValidPEMPrivateKey, isValidPEMKey,
  splitIntoChunks, joinChunks,
} from 'encrypt-rsa';

isValidRSAPublicKey

isValidRSAPublicKey(key: unknown): Promise<boolean> parses SPKI PEM key material through platform cryptography. Returns false for malformed, non-RSA, or wrong-role keys.

isValidRSAPrivateKey

isValidRSAPrivateKey(key: unknown): Promise<boolean> parses PKCS#8 PEM RSA private key material. Returns false for malformed, non-RSA, or wrong-role keys.

These helpers do not establish that two keys match or satisfy your application's strength policy. Node cryptographic operations additionally accept legacy PKCS#1 keys, while strict validators and browser operations use SPKI/PKCS#8.

isValidPEMPublicKey

isValidPEMPublicKey(key: unknown): boolean checks public PEM header/footer text only.

isValidPEMPrivateKey

isValidPEMPrivateKey(key: unknown): boolean checks private PEM header/footer text only.

isValidPEMKey

isValidPEMKey(key: unknown): boolean accepts either of the formatting checks above. All formatting helpers are synchronous and return false for non-string input.

Formatting is not validation

A correctly labeled PEM block may still contain invalid key material. Use the asynchronous RSA validators when validating a key supplied by an application.

splitIntoChunks

splitIntoChunks(text: string, chunkSize = 214): string[] splits text on Unicode code-point boundaries using UTF-8 byte counts. The default is the direct RSA/SHA-1 capacity of a 2048-bit key. Empty text returns ['']. A chunk size smaller than one encoded character cannot provide that byte bound.

Prefer authenticated hybrid encryption for long data. Independently encrypted chunks do not authenticate their order or completeness.

joinChunks

joinChunks(chunks: string[]): string concatenates chunks without separators.