| 1 | const { createCipheriv, createDecipheriv, getCiphers } = require('crypto')
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| 2 |
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| 3 | const { KEYOBJECT } = require('../help/consts')
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| 4 | const { asInput } = require('../help/key_object')
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| 5 |
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| 6 | const checkInput = (data) => {
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| 7 | if (data !== undefined && data.length % 8 !== 0) {
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| 8 | throw new Error('invalid data length')
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| 9 | }
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| 10 | }
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| 11 |
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| 12 | const wrapKey = (alg, { [KEYOBJECT]: keyObject }, payload) => {
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| 13 | const key = asInput(keyObject, false)
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| 14 | const cipher = createCipheriv(alg, key, Buffer.alloc(8, 'a6', 'hex'))
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| 15 |
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| 16 | return { wrapped: Buffer.concat([cipher.update(payload), cipher.final()]) }
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| 17 | }
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| 18 |
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| 19 | const unwrapKey = (alg, { [KEYOBJECT]: keyObject }, payload) => {
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| 20 | const key = asInput(keyObject, false)
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| 21 | checkInput(payload)
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| 22 | const cipher = createDecipheriv(alg, key, Buffer.alloc(8, 'a6', 'hex'))
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| 23 |
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| 24 | return Buffer.concat([cipher.update(payload), cipher.final()])
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| 25 | }
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| 26 |
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| 27 | module.exports = (JWA, JWK) => {
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| 28 | ['A128KW', 'A192KW', 'A256KW'].forEach((jwaAlg) => {
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| 29 | const size = parseInt(jwaAlg.substr(1, 3), 10)
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| 30 | const alg = `aes${size}-wrap`
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| 31 | if (getCiphers().includes(alg)) {
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| 32 | JWA.keyManagementEncrypt.set(jwaAlg, wrapKey.bind(undefined, alg))
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| 33 | JWA.keyManagementDecrypt.set(jwaAlg, unwrapKey.bind(undefined, alg))
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| 34 | JWK.oct.wrapKey[jwaAlg] = JWK.oct.unwrapKey[jwaAlg] = key => (key.use === 'enc' || key.use === undefined) && key.length === size
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| 35 | }
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| 36 | })
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| 37 | }
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