+// JSONLD
+
+function isJsonLDSignatureVerified (fromActor: MActor, signedDocument: any): Promise<boolean> {
+ if (signedDocument.signature.type === 'RsaSignature2017') {
+ return isJsonLDRSA2017Verified(fromActor, signedDocument)
+ }
+
+ logger.warn('Unknown JSON LD signature %s.', signedDocument.signature.type, signedDocument)
+
+ return Promise.resolve(false)
+}
+
+// Backward compatibility with "other" implementations
+async function isJsonLDRSA2017Verified (fromActor: MActor, signedDocument: any) {
+ const [ documentHash, optionsHash ] = await Promise.all([
+ createDocWithoutSignatureHash(signedDocument),
+ createSignatureHash(signedDocument.signature)
+ ])
+
+ const toVerify = optionsHash + documentHash
+
+ const verify = createVerify('RSA-SHA256')
+ verify.update(toVerify, 'utf8')
+
+ return verify.verify(fromActor.publicKey, signedDocument.signature.signatureValue, 'base64')
+}
+
+async function signJsonLDObject (byActor: MActor, data: any) {
+ const signature = {
+ type: 'RsaSignature2017',
+ creator: byActor.url,
+ created: new Date().toISOString()
+ }
+
+ const [ documentHash, optionsHash ] = await Promise.all([
+ createDocWithoutSignatureHash(data),
+ createSignatureHash(signature)
+ ])
+
+ const toSign = optionsHash + documentHash
+
+ const sign = createSign('RSA-SHA256')
+ sign.update(toSign, 'utf8')
+
+ const signatureValue = sign.sign(byActor.privateKey, 'base64')
+ Object.assign(signature, { signatureValue })
+
+ return Object.assign(data, { signature })