+// Backward compatibility with "other" implementations
+async function isJsonLDRSA2017Verified (fromActor: ActorModel, signedDocument: any) {
+ function hash (obj: any): Promise<any> {
+ return jsonld.promises
+ .normalize(obj, {
+ algorithm: 'URDNA2015',
+ format: 'application/n-quads'
+ })
+ .then(res => sha256(res))
+ }
+
+ const signatureCopy = cloneDeep(signedDocument.signature)
+ Object.assign(signatureCopy, {
+ '@context': [
+ 'https://w3id.org/security/v1',
+ { RsaSignature2017: 'https://w3id.org/security#RsaSignature2017' }
+ ]
+ })
+ delete signatureCopy.type
+ delete signatureCopy.id
+ delete signatureCopy.signatureValue
+
+ const docWithoutSignature = cloneDeep(signedDocument)
+ delete docWithoutSignature.signature
+
+ const [ documentHash, optionsHash ] = await Promise.all([
+ hash(docWithoutSignature),
+ hash(signatureCopy)
+ ])
+
+ const toVerify = optionsHash + documentHash
+
+ const verify = createVerify('RSA-SHA256')
+ verify.update(toVerify, 'utf8')
+
+ return verify.verify(fromActor.publicKey, signedDocument.signature.signatureValue, 'base64')
+}
+