25 lines
597 B
Go
25 lines
597 B
Go
package pathiv
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import (
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"crypto/sha256"
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"github.com/rfjakob/gocryptfs/internal/nametransform"
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)
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type Purpose string
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const (
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PurposeDirIV Purpose = "DIRIV"
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PurposeFileID Purpose = "FILEID"
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PurposeSymlinkIV Purpose = "SYMLINKIV"
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PurposeBlock0IV Purpose = "BLOCK0IV"
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)
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// Derive derives an IV from an encrypted path by hashing it with sha256
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func Derive(path string, purpose Purpose) []byte {
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// Use null byte as separator as it cannot occur in the path
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extended := []byte(path + "\000" + string(purpose))
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hash := sha256.Sum256(extended)
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return hash[:nametransform.DirIVLen]
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}
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