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ring perform raw RSA decryption of data

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Joker answered on May 19, 2022 Popularity 1/10 Helpfulness 1/10

answer ring perform raw RSA decryption of data

related ring perform raw RSA encryption on data

related ring perform raw RSA decryption of data

ring perform raw RSA decryption of data

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/* decrypt a file by first decrypting AES key that was used to encrypt it
 * and then decrypt the whole content using the AES key
 /* We decrypt AES using rsa_decrypt_raw and then remove padding manually
 */
try
        /* read Alice private key */
        rsaKeyPEM = Read("alice_private_key.pem")
        rsaKey = rsa_import_pem(rsaKeyPEM)

        /* calculate the modulus length */
        rsaKeyParams = rsa_export_params(rsaKey)
        modulusLen = rsaKeyParams[:bits]/ 8

        /* read encrypted file */
        cEncryptedContent = Read ("encrypted_document.enc")

        /* IV is the first 16 bytes if the file */
        cIV = substr(cEncryptedContent, 1, 16)

        /* encrypted key follows IV and its length is modulusLen */
        cEncryptedKey = substr(cEncryptedContent, 17, modulusLen)

        /* encrypted data follows the key */
        cEncryptedData = substr(cEncryptedContent, 17 + modulusLen)

        /* decrypt the AES-128 key */
        cPaddedKey = rsa_decrypt_raw(rsaKey,cEncryptedKey)

        /* remove PKCS1 padding */
        paddedInputLength = len(cPaddedKey)
        cKey = ""
        if paddedInputLength > 11 AND Ascii(cPaddedKey[1]) = 0 AND Ascii(cPaddedKey[2]) = 2
                zeroFound = false
                for j = 3 to paddedInputLength
                        if Ascii(cPaddedKey[j]) = 0
                                i = j
                                zeroFound = true
                                exit
                        ok
                next

                if zeroFound
                        if i = paddedInputLength
                                /* unpadded data is empty */
                                Raise("Empty data recovered from padding")
                        else
                                cKey = substr(cPaddedKey,i+1)
                        ok
                else
                        Raise ("Invalid data padding")
                ok
        else
                Raise("the decrypted data is invalid")
        ok

        /* decrypt the data using the AES-128 key */

        cPlainData = Decrypt(cEncryptedData,cKey,cIV,"aes128")

        /* store the decrypted data to a file */
        Write("decrypted_document.txt", cPlainData)

catch
        See "Unexpected error occured: " + cCatchError + nl
done

Popularity 1/10 Helpfulness 1/10 Language whatever

Source: ring-lang.github.io

Tags: raw ring rsa whatever

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Contributed on May 19 2022

Joker

0 Answers Avg Quality 2/10

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ring perform raw RSA encryption on data

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rsa_encrypt_raw(pRsaKey,cPlainData) ---> return a string containing the raw RSA encryption of cPlainData

Popularity 2/10 Helpfulness 1/10 Language whatever

Source: ring-lang.github.io

Tags: ring raw rsa whatever encryption

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Contributed on May 19 2022

Joker

0 Answers Avg Quality 2/10

ring perform raw RSA encryption on data

Comment

/* encrypt a file using AES key and then encrypt the AES key using an RSA public key using PKCS1 padding */
/* we manually add PKCS1 padding and then perform raw RSA encryption */
try
        /* read Alice public key */
        rsaPublicKeyPEM = Read("alice_public_key.pem")
        rsaPublicKey = rsa_import_pem(rsaPublicKeyPEM)

        /* encrypt file with random AES-128 key */
        cData = Read ("secret_document.txt")
        cKey = RandBytes(16)
        cIV = RandBytes(16)
        cEncryptedData = Encrypt(cData,cKey,cIV,"aes128")

        /* encrypt the AES-128 key with the RSA public key */

        /* calculate the modulus length */
        rsaKeyParams = rsa_export_params(rsaPublicKey)
        modulusLen = rsaKeyParams[:bits]/ 8

        /* we manually add PKCS1 padding */
        paddingSize = modulusLen - Len(cKey) - 2 - 1
        paddingStr = space (paddingSize)

        /* encryption case. Add random bytes */
        for i=1 to paddingSize
                paddingStr[i] = Char (1 + Random(254))
        next

        paddedData = Char(0) + Char(2) + paddingStr + Char (0) + cKey

        cEncryptedKey = rsa_encrypt_raw(rsaPublicKey,paddedData)

        /* store IV, encrypted AES key and encrypted data in a file to be sent to Alice*/
        Write("raw_encrypted_document.enc", cIV + cEncryptedKey + cEncryptedData)

catch
        See "Unexpected error occured: " + cCatchError + nl
done

Popularity 2/10 Helpfulness 1/10 Language whatever

Source: ring-lang.github.io

Tags: whatever rsa raw encryption ring

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Contributed on May 19 2022

Joker

0 Answers Avg Quality 2/10

ring perform raw RSA decryption of data

Comment

rsa_decrypt_raw(pRsaKey,cEncryptedData) ---> return a string containing the decryption of cEncryptedData

Popularity 1/10 Helpfulness 1/10 Language whatever

Source: ring-lang.github.io

Tags: rsa whatever raw ring

Link to this answer
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Contributed on May 19 2022

Joker

0 Answers Avg Quality 2/10

ring perform raw RSA decryption of data

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ring perform raw RSA encryption on data

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