Decrypt RSA-OAEP ciphertext

Decrypt a small RSA-OAEP message and verify its padding parameters.

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ToolRSA-OAEP Decrypt
Input
Output
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Preview

How it works

The private key recovers the encoded message, OAEP padding and label hash are checked, and the mask is removed to return bytes. Hash and label must match the encryption parameters.

  • Random padding prevents deterministic ciphertext.
  • SHA-256 is a common modern parameter.

Worked example

RSA Decrypt
Decrypt RSA-OAEP ciphertext using the private key
Input
											Input: sCu3KkWG3MdUhPg+WMn/2D/uw0pPFNKhS1LKzRhpMqcQcSc7OVXl5dVW+P/bzPKloJ0FZ/DdkXyCO7GuglAyHwMKh3SpMES8Ryo0dJYIIPRODdnXkqWhxNXQjTkVDNAvlj9B3R7wQ7uZE/9JE1WsQsPeKu784NLGXX18Th5f7RIaYCqIE3lRQrvtvNeC21ePggbYMJRCQCaYVcvgHuazL26Y9yZIyU6vLRYpeXq1/ru5RkX47TzzGSUjHKBEnEbAaLSu4SW5YMHjljqKP5yC2b5zWK9rmmOz7ULKnCgWNlgvzWgOaalq3hnve0ZuP/2V5kslRMFuxsSbZRAXO+Q3xg==
Private key: {"alg":"RSA-OAEP-256","d":"JlAkQY1xOkjkwJ4kjy_5RFtufzQOqvpD1NGtfAq9WTG2_u4O0tnNXtqaf9VueyIQk-IYqEsEetZLvYt9yrUkQ61JE6L-NEDuTcs2bpuCXdRCOniUWSC63nNWC9x7xdDBoEb7gwRanvU69tbHeKx5bfdvCXhBRFH4ytM6DK763zjRaIkgjSuk0d9qyItsLQQ0tBTANjVI3_6aP6xPuM8N6gzxludHaQvYApPZapBgAs8iii5nlwoEpgBxacd25aWn3-oS6hlaimSignU6h5MlqAnpUqwroWZb-ynoxr4DVG46ka9eVDsce4KjbQb4qlzgMav-7wzkbVRVkBTWD0-zgQ","dp":"tmXpFJtDFtU7Gr4fsi6y8T3no6Xd-3DVVx0xCQmyP9EigTeRGYHdrZ1Wy2Vx37ssTliRB0MUB-KpRZNgUHZmf1nF_iejsaiuliZJ7z-O3hdgpkj8RoxVQTKN_C0MyUEa3PRjf141zJGSkgroWU-smCL72pi_O0NaBGG41edVukU","dq":"wjKIvlzgzX2H_guuGDRL2rWzBdFmIwgzAM6G1f9CPiYXBqU2lLNvXInpya-FJDy299E79bIai0zWO5jFre9PtqzT0OK-Ek5RDa7oLcNPd8rWXRGf2751wwtjx1iMXIGej_KQVgCz54PhswUUUT3qTMOjD1k8cmn2mvQEc4em_aE","e":"AQAB","ext":true,"key_ops":["decrypt"],"kty":"RSA","n":"1Nga8f8mHyoZglSdI9bHbySgjbdB4h320pIB0Rap6bcMGePIuh3SOfCJBqkYuqK0HMoWDlvPQfbl-kw9rUxXbVa1pxK5WUdMSvFba4Y9AdususV94Ls7M-PjE94NdfQNegjkgWsgjrLljHYZuY8o9VIHGAzn8lsJJzaNWsuVdI2s_Lba3Qws__wq9sl9J3pxahg3xvbt_XIKpU6Xk3kBSRIeE_oT5x2SjxSU_DyzpVvT0OWe0k3-Hc-GMoDxGy79ZtCpIJHlMlYYDJZQOeniD7rgwZC1ePwx_PrUNusTSx3ok5n7VxP7XeLs4pANcipqKhcfp9k3NXnumcbNMH1WpQ","p":"8Ii7MAQpHhRgvV1zUmVPQu8iYc8Keqo7KqZQHObvh3AQ_ZL7NbIzvxbwwucUbj3N8sQP98d6KoLrQdyUZTmfDYX5f7ENOtgi0PK5yqwH1p3Lvov4w-oIwTCzVpTyfWvXYLh1A4bui-oCmsKtQdPX4aBSPf4qT-ievQ8AX8W0-cU","q":"4oeWsYC2vwejksA9sevCl3BnbmSnWsENNHK7ZQOrSo9mTVysAkmWoBhhBBfaSfqzoVo9wSNmnXZH8yC3mrjGb-uPxWohdXlQnmvqmwUtYjMIsFswjmADXEea7iKjMVMOkLYwnu_RvjYzdN_LwZXpnxKx1kpxnHNbpAZJCgwyF2E","qi":"4BtUCzazrMnnhd3iJBR_VykjyocLM1zBkasElcejxQN0EBc4X6z63zUSsTUhElOGdFRJROBEA2Ohd2W-ieogHJsQKkko6Y_33c9hLXWtwZRnnzEFVrzcOFjSNcJ-WHcGETjv15WK4zxpU2i0SX3qpzw19s801F6orxT1sygy_FY"}
										
Output
												utils tools test message
											

When to use this

Key wrapping, configuration secrets, and interoperability tests decrypt OAEP.

Edge cases

  • Messages over the modulus-dependent limit cannot fit.
  • Wrong label or hash yields decryption failure.
  • RSA-OAEP is for small secrets, not bulk files.

References