RSA

This library uses the Cryptop++ PEM_PACK to parse and store RSA keys in the PEM format.

Generate Key Pair

const rsa_keypair = Cryptopp.RSA.generateKeyPair(2048);

Returns: Object containing the public and private keys, as well as the parameters used to generate the keys.

{
    public: "...",
    private: "...",
    params: {
        n: "...",
        p:"...",
        q:"...",
        d:"...",
        e:"...",
    },
};

Example of a returned public/private key:

-----BEGIN FOO BAR KEY-----
MIIBgjAcBgoqhkiG9w0BDAEDMA4ECKZesfWLQOiDAgID6ASCAWBu7izm8N4V
2puRO/Mdt+Y8ceywxiC0cE57nrbmvaTSvBwTg9b/xyd8YC6QK7lrhC9Njgp/
...
-----END FOO BAR KEY-----

Encrypt

Encrypts a message using the public key.

const publicKey = ... // obtained from second party
const encrypted = Cryptopp.RSA.encrypt(data, publicKey, 'OAEP_SHA1');

Parameters

Parameter	Type	Required
data	string ArrayBuffer	✅
publicKey	string	✅
encryptionScheme	"OAEP_SHA1" "OAEP_SHA256" "PKCS1v15"	✅

Returns: Based on data input type: ArrayBuffer or base64-encoded string

Decrypt

Decrypts a message using the private key.

const rsa_keypair = ... // some locally stored keypair
const encryptedData = Cryptopp.RSA.encrypt(data, rsa_keypair.private, 'OAEP_SHA1');

Parameters

Parameter	Type	Required
data	base64-encoded string ArrayBuffer	✅
privateKey	string	✅
encryptionScheme	"OAEP_SHA1" "OAEP_SHA256" "PKCS1v15"	✅

Returns: Based on data input type: ArrayBuffer or string

Sign

Signs a message with a private key to ensure authenticity.

const rsa_keypair = ... // some locally stored keypair
const signedData = Cryptopp.RSA.sign(encryptedData, rsa_keypair.private, 'PKCS1v15_SHA1');

Parameters

Parameter	Type	Required
data	string ArrayBuffer	✅
privateKey	string	✅
signatureScheme	"PKCS1v15_SHA1" "PKCS1v15_SHA256" "PSSR_SHA1" "PSSR_SHA256" "PSSR_Whirlpool" "PSS_SHA1" "PSS_SHA256" "PSS_Whirlpool"	✅

Note: Crypto++ supports two broad categories of digital signatures: Signature Schemes with Appendix (PKCS1v15_SHA1 and PKCS1v15_SHA256) and Signature Schemes with Recovery (PSSR_SHA1, PSSR_SHA256, and PSSR_Whirlpool).

A signature scheme with appendix requires the verifier to have three items: the public key, the message, and the signature. Can be verified using the Cryptopp.RSA.verify function.

A signature scheme with recovery requires only the public key and signature - the message is recovered from the signature. Can be recovered using the Cryptopp.RSA.recover function.

Returns: Based on data input type: ArrayBuffer or base64-encoded string

Verify

Valides signature of a message.

const data = ...
const dataSignature = ...
const publicKey = ... // obtained from second party
const isSignatureValid = Cryptopp.RSA.verify(signedData, publicKey, 'PKCS1v15_SHA1', dataSignature);

Parameters

Parameter	Type	Required
data	base64-encoded string ArrayBuffer	✅
publicKey	string	✅
signatureScheme	"PKCS1v15_SHA1" "PKCS1v15_SHA256" "PSS_SHA1" "PSS_SHA256" "PSS_Whirlpool"	✅
signature	base64-encoded string ArrayBuffer	✅

Returns: true if the signature is valid, false otherwise.

Recover

Recovers the message from the signature using the public key.

// In this case, data has to be signed with PSSR and will be then distributed as the message
const data = ...
const rsa_keypair = ... // some locally stored keypair
const signature = Cryptopp.RSA.sign(data, rsa_keypair.private, 'PSSR_SHA1');

// Recipient can now verify the signature and recover the message
const publicKey = ... // obtained from second party
try {
    const recoveredData = Cryptopp.RSA.recover(signature, publicKey, 'PSSR_SHA1');
} catch (e) {
    // handle error if signature doens't match the key
}

Parameters

Parameter	Type	Required
signature	base64-encoded string ArrayBuffer	✅
publicKey	string	✅
signatureScheme	"PSSR_SHA1" "PSSR_SHA256" "PSSR_Whirlpool"	✅

Returns: Based on data input type: ArrayBuffer or string

Throws error if the signature doesn't match the key