db[len(db)-len(msg)-1] = 1 copy(db[len(db)-len(msg):], msg) if err := drbg.ReadWithReader(random, seed); err != nil { return nil, err } mgf1XOR(db, mgfHash, seed) mgf1XOR(seed, mgfHash, db) return encrypt(pub, em) } // DecryptOAEP decrypts ciphertext using RSAES-OAEP. func DecryptOAEP(hash, mgfHash hash.Hash, priv *PrivateKey, ciphertext []byte, label []byte) ([]byte, error) { fipsSelfTest() fips140.RecordApproved() checkApprovedHash(hash) k := priv.pub.Size() if len(ciphertext) > k || k < hash.Size()*2+2...