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Add base64 explanation

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This commit is contained in:
Miroslav Vasilev 2024-10-28 00:12:43 +02:00
parent ccfaaf39f8
commit 635e727741
1 changed files with 6 additions and 0 deletions
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6
set1/challenge_1.go
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@ -111,6 +111,12 @@ func HexToBase64(hexValue string) (base64 string, success bool) {
originals := plainBuffer[i : i+3] originals := plainBuffer[i : i+3]
// Base64 splits up 3 bytes into 4 by first taking all 24 bits of the original 3 bytes and splitting them evenly across 4 6-bit words
// Example: byte A: 0bAAAAAAAA, byte B: 0bBBBBBBBB, byte C: 0bCCCCCCCC
// Base64 Result: 0b00AAAAAA, 0b00AABBBB, 0b00BBCCCC, 0b00CCCCCC
// This expands the size of the original data by ~33%
// If the byte size of the original data is not divisible by 3, the missing bytes are padded out to 0s and the padding character = is used to the end of the base64 string
first := originals[0] >> 2 first := originals[0] >> 2
second := (0b00110000 & (originals[0] << 4)) ^ (originals[1] >> 4) second := (0b00110000 & (originals[0] << 4)) ^ (originals[1] >> 4)
third := (0b00111100 & (originals[1] << 2)) ^ (originals[2] >> 6) third := (0b00111100 & (originals[1] << 2)) ^ (originals[2] >> 6)